Disorders of Melanocytes
Acquired Nevomelanocytic Nevi (NMN) 
NMN, commonly called moles, are very common, small (<1 cm), circumscribed, acquired pigmented macules, papules, or nodules.
Composed of groups of melanocytic nevus cells located in the epidermis, dermis, and, rarely, subcutaneous tissue.
They are benign, acquired tumors arising as nevus cell clusters at the dermal–epidermal junction (junctional NMN), invading the papillary dermis (compound NMN), and ending their life cycle as dermal NMN with nevus cells located exclusively in the dermis where, with progressive age, there will be fibrosis.
Epidemiology and Etiology
One of the most common acquired new growths in Caucasians (most adults have about 20 nevi), less common in blacks or pigmented persons, and sometimes absent in persons with red hair and marked freckling (skin phototype I).
Race. Blacks and Asians have more nevi on the palms, soles, and nail beds.
Heredity. Common acquired NMN occur in family clusters. Dysplastic melanocytic nevi (DN) (see Section 12), which are putative precursor lesions of malignant melanoma, are different from NMN and occur in virtually every patient with familial cutaneous melanoma and in 30–50% of patients with sporadic nonfamilial primary melanoma.
Sun Exposure. A factor in the induction of nevi on the exposed areas.
Significance. Risk of melanoma is related to the numbers of NMN and to DN. In the latter, even if only a few lesions are present.
Clinical Manifestation
Duration and Evolution of Lesions. NMN appear in early childhood and reach a maximum in young adulthood even though some NMN may arise in adulthood. Later on there is a gradual involution and fibrosis of lesions, and most disappear after the age of 60. In contrast, DN continue to appear throughout life and are believed not to involute (see Section 12).
Skin Symptoms. NMN are asymptomatic. However, NMN grow and growth is often accompanied by itching. Itching per se is not a sign of malignancy, but if a lesion persistently itches or is tender, it should be followed carefully or excised, since persistent pruritus may be an early indication of malignant change.
Classification
NMN are multiple (Fig. 9-1A) and can be classified according to their state of evolution and thus according to the histologic level of the nevus cell clusters (Fig. 9-1B).
Figure 9-1. (A) Multiple NMN on the shoulder of a 32-year-old female. Most of these nevi are junctional NMN; some are slightly elevated and thus compound NMN. Note relatively uniform shape and color of the lesions. Because of different developmental stages, they are of varying size ranging from 1 to 4 mm in diameter and they are regular and have a relatively uniform shape. (B) Junctional NMNarise at dermal–epidermal junction and are intraepidermal, pigmented, and flat. In compound NMN, nevus cells have invaded the dermis and are thus both intraepidermal and dermal. Since, as a rule, only junctional nevus cells have the capacity to form melanin, they are still pigmented, but since they continue to grow, they are more elevated than junctional NMN. In dermal NMN, all nevus cells are now in the dermis and have lost the capacity to produce melanin. Dermal NMN are thus skin-colored, pink, or only slightly tan. As they still grow and expand into the dermis, they lift the lesion upward and are thus usually dome-shaped or papillomatous.
1. Junctional melanocytic NMN: These arise at the dermal–epidermal junction, on the epidermal side of the basement membrane; in other words, they are intraepidermal (Figs. 9-1B and 9-2).
2. Compound NMN: Nevus cells invade the papillary dermis, and nevus cell nests are now found both intraepidermally and dermally (Figs. 9-1B and 9-3).
3. Dermal melanocytic NMN: These represent the last stage of the evolution of NMN. “Dropping off” into the dermis is now completed, and the nevus grows or remains intradermal (Figs. 9-1B and 9-4). With progressive age, there will be gradual fibrosis (Fig. 9-4C).
Figure 9-2. (A-D) Junctional NMN Lesions are completely flat (A, B) or minimally elevated as in (C) and (D). They are symmetric with a regular border and, depending on the skin type of the individuals, have different shades of brown to black (D).
Figure 9-3. Compound NMN Uniformly pigmented papules and small domed nodules. (A) The lesion to the left is flatter and tan with a more elevated darker center; the larger lesion (on the right) is older and chocolate-brown; the left lesion is younger and has a predominantly junctional component at the periphery. (B) A heavily pigmented dome-shaped lesion in the eyebrow. It is sharply defined, uniformly black, smooth and slightly cobblestone-like surface, and sharply and regularly defined. It measures less than 5 mm.
Figure 9-4. Dermal melanocytic NMN (A) Two dome-shaped, sharply defined relatively soft tan nodules on the left cheek and right lateral mandibular region in a 60-year-old male. These lesions were previously much darker and less elevated. (B) A larger magnification of a dermal NMN. This lesion is sharply defined, has a reddish color with a central regular pigmented spot where the nevus obviously is still compound in nature. (C) Old dermal nevus on the upper lip of a 65-year-old woman. This lesion is relatively hard, has a smooth surface, and a pinkish color. This lesion is fibrosing.
Thus, melanocytic NMN undergo the evolution from junctional → compound → dermal NMN (Fig. 9-1B). Since the capacity of NMN cells to form melanin is greatest when they are located at the dermal–epidermal junction (intraepidermally) and since NMN cells lose their capacity for melanization, the further they penetrate into the dermis, the lesser is the intensity of pigmentation with the increase in the dermal proportion of the nevus. Purely dermal NMN are therefore almost always without pigment. In a simplified manner, the clinical appearance of NMN along this evolutionary path can be characterized as follows: junctional NMN is flat and dark, compound NMN is raised and dark, and dermal NMN is raised and light. This evolution also reflects the age at which the different types of NMN are found. Junctional and compound NMN are usually seen in childhood and through the teens, whereas dermal NMN start manifesting in the third and fourth decade.
Junctional Melanocytic Nevocellular Nevi
Lesions. Macule, or only very slightly raised (Fig. 9-2). Uniform tan, brown, dark brown, or even black. Round or oval with smooth, regular borders. Scattered discrete lesions. Never >1 cm in diameter; if >1 cm, the “mole” is a congenital nevomelanocytic nevus, a DN, or a melanoma (see Section 12).
Compound Melanocytic Nevocellular Nevi
Lesions. Papules or small nodules (Fig. 9-3). Dark brown, sometimes even black; dome-shaped, smooth or cobblestone-like surface, regular and sharply defined border, sometimes papillomatous or hyperkeratotic. Never >1 cm in diameter; if >1 cm, the mole is a congenital nevomelanocytic nevus, a DN, and a melanoma. Consistency either firm or soft. Color may become mottled as progressive conversion into dermal NMN occurs. May have hairs.
Dermal Melanocytic Nevocellular Nevi
Lesions. Sharply defined papule or nodule. Skin-colored, tan or flecks of brown, often with telangiectasia. Round, dome-shaped (Fig. 9-4), smooth surface, diameter <1 cm. Usually not present before the second or third decade. Older lesions, mostly on the trunk, may become pedunculated and do not disappear spontaneously. May be hairy.
Distribution. Face, trunk, extremities, scalp. Random. Occasionally palmar and plantar, in which case these NMN usually have the appearance of junctional NMN.
Diagnosis and Differential Diagnosis
Diagnosis. Made clinically. As for all pigmented lesions, the ABCDE rule applies (see Section 12). In case of doubt, apply dermoscopy (epiluminescence microscopy), and if malignancy cannot be excluded even by this procedure, excise lesions with a narrow margin.
Differential Diagnosis. Junctional NMN: all flat, deeply pigmented lesions. Solar lentigo, flat atypical nevus, and lentigo maligna. Compound NMN: all raised pigmented lesions. Seborrheic keratosis, DN, small superficial spreading melanoma, early nodular melanoma, pigmented basal cell carcinoma (BCC), dermatofibroma, Spitz nevus, and blue nevus. Dermal NMN: all light tan or skin-colored papules. BCC, neurofibroma, trichoepithelioma, dermatofibroma, and sebaceous hyperplasia.
Management
Indications for removal of acquired melanocytic NMN are the following:
Site: Lesions on the scalp (only if difficult to follow and not a classic dermal NMN); mucous membranes, anogenital area.
Growth: If there is rapid change in size.
Color: If color becomes variegated.
Border: If irregular borders are present or develop.
Erosions: If lesion becomes eroded without major trauma.
Symptoms: If lesion begins to persistently itch, hurt, or bleed.
Dermoscopy: If criteria for melanoma or a dysplastic nevus are present or appear de novo.
Melanocytic NMN never become malignant because of manipulation or trauma. In those cases where this was claimed, the lesion was initially a misdiagnosed melanoma. If there is an indication for the removal of an NMN, the nevus should always be excised for histologic diagnosis and for definite treatment (particularly applicable to and decisive in ruling out congenital, dysplastic, or blue nevi). Removal of papillomatous, compound, or dermal NMN for cosmetic reasons by electrocautery requires that a nevus be unequivocally diagnosed as benign NMN and histology be performed. If an early melanoma cannot be excluded with certainty, an excision for histologic examination is obligatory but can be performed with narrow margins.
Halo Nevomelanocytic Nevus ICD-9: 216.9 ICD-10: D22-M8723/0
An NMN that is encircled by a halo of leukoderma or depigmentation. The leukoderma is based on a decrease of melanin in melanocytes and/or disappearance of melanocytes at the dermal–epidermal junction (Fig. 9-5A).
Mechanism: autoimmune (cellular, humoral) mechanism leading to apoptosis of nevus cells and melanocytes in surrounding epidermis.
Prevalence 1%. Occurs spontaneously or in patients with vitiligo.
A white halo around a NMN indicates regression and halo nevi most often undergo spontaneous involution.
Usually in children or young adults mostly on the trunk (Fig. 9-5A).
Three stages: (1) white halo around preexisting NMN (Fig. 9-5B), may be preceded by erythema (Fig. 9-5C); (2) disappearance of NMN (months to years) (Fig. 9-5A); and (3) repigmentation of halo (years).
Halo NMN may indicate incipient vitiligo.
Halo around other lesions: blue nevus, congenital NMN, Spitz nevus, malignant melanoma and melanoma metastases, dermatofibroma, neurofibroma.
Synonym: Sutton leukoderma acquisitum centrifugum.
Figure 9-5. (A) Halo melanocytic NMN on the back of a 22-year-old female There are five halo nevi, all with a pigmented dot-like central junctional or compound NMN surrounded by a hypo- or amelanotic halo. The arrow indicates one lesion where the central nevus has completely regressed; the reddish color indicates telangiectasia. (B) Larger magnification of a halo NMN. The nevus is a junctional NMN (compare with Fig. 9-2) that is surrounded by a hypomelanotic (almost white) halo. (C) Several tan junctional NMN that are surrounded by an erythematous halo. This is the early stage of halo development. The erythematous rim will later be replaced turn white.
Blue Nevus ICD-9: 216.9 ° ICD-10: D22. M8780 
A blue nevus is an acquired, firm, dark-blue to gray-to-black, sharply defined papule or nodule representing a localized proliferation of melanin-producing dermal melanocytes.
Three types: common blue nevus, cellular blue nevus, combined NMN/blue nevus.
Blue nevi and combined NMN/blue nevi are benign. Cellular blue nevi are larger and have very rare tendency to become malignant.
Ectopic accumulation of melanin-producing melanocytes; derived from melanoblasts arrested during migration from neural crest.
Papules, nodules, blue-gray, blue-black, <10 mm in diameter (Figs. 9-6 and 9-7A). Cellular blue nevi larger (>1 cm) and irregular (Fig. 9-7B).
Differential diagnosis: dermatofibroma, glomus tumor, nodular or metastatic melanoma, traumatic tattoo, pigmented BCC.
Treatment not necessary. If in doubt, excision.
Cellular blue nevi should be excised.
Synonyms: Blue neuronevus, dermal melanocytoma.
Figure 9-6. Blue nevus There are four tan junctional NMN and one bluish-black round lesion on the cheek of a 17-year-old girl. In contrast to the junctional NMN, the blue nevus is palpable with a relatively high consistency, and upon dermoscopy will appear as an ill-defined uniformly bluish lesion deep in the dermis.
Figure 9-7. Blue nevus and cellular blue nevus (A) This blue nevus has regular borders but is not circular and is solidly blue-black in color. The epidermis is smooth, indicating that the lesion is in the dermis. The consistency is increased and the margins are well defined. Differential diagnosis must include nodular melanoma. (B) This cellular blue nevus appeared as two large, bluish-black nodules on the scalp. After excision, histology showed that they were contiguous and thus represented one single lesion. Cellular blue nevi are much larger and should always be excised to rule out melanoma, which, albeit rarely, can develop in these lesions.
Nevus Spilus ICD-9: 216.9 ° ICD-10: D22
Light brown pigmented macule varying from a few centimeters to a large area (>15 cm), and many dark brown small macules (2–3 mm) or papules scattered throughout the pigmented background (Fig. 9-8A). The pigment in the macular background may be so faint that it can be recognized only under Wood light (Fig. 9-8B).
The pathology of the macular pigmented lesion is the same as lentigo simplex, i.e., increased numbers of melanocytes, while the flat or raised lesions scattered throughout are either junctional or compound; rarely, these may be DN.
The lesions are not as common as junctional or compound NMN but are not at all rare. In one series, the nevus spilus was present in 3% of white patients.
Malignant melanoma very rarely arises in these lesions.
Figure 9-8. Nevus spilus (A) This dark brown pigmented macule measuring about 10 cm along the long axis is peppered with many small, dark brown to black macules and papules. (B) This is also nevus spilus but the macular background is only slightly pigmented so that it will be revealed only under Wood light. The lesion is peppered with many small dark brown macules and flat papules.
Spitz Nevus ICD-9: 216.9 ° ICD-10: D22-M8772
Spitz nevus is a benign, dome-shaped, hairless, small (<1 cm in diameter) nodule, most often pink, red or tan (Fig. 9-9A). There is often a history of recent rapid growth.
Incidence is 1.4:100,000 (Australia). It occurs at all ages but a third of the patients are children <10 years; rarely seen in persons >40 years. Lesions arise within months. They are papules or dome-shaped or relatively flat nodules, round, well-circumscribed, smooth-topped, and hairless. They are a uniform pink-red (Fig. 9-9A), tan, brown, dark brown, or even black (Fig. 9-9B); are firm; and usually distributed on the head and neck.
Differential diagnosis includes all pink, tan, or darkly pigmented papules: pyogenic granulom, hemangioma, molluscum contagiosum, juvenile xanthogranuloma, mastocytoma, dermatofibroma, NMN, DN (amelanotic), nodular melanoma.
Dermatopathology: hyperplasia of the epidermis and melanocytes and dilation of capillaries. Admixed large epithelioid cells, large spindle cells with abundant cytoplasm, and occasional mitotic figures. Sometimes bizarre cytologic patterns: nests of large cells extend from the epidermis (“raining down”) into the reticular dermis as fascicles of cells form an “inverted triangle,” with the base lying at the dermal–epidermal junction and the apex in the reticular dermis.
Histologic examination must be done to confirm the clinical diagnosis. Excision in its entirety is important because the condition recurs in 10–15% of all cases in lesions that have not been excised completely. Spitz nevi are benign, but there can be a histologic similarity to melanoma and the histopathologic diagnosis requires the help of an experienced dermatopathologist.
Spitz nevi do not usually involute, as do common acquired NMN nevi. However, some lesions have been observed to transform into common compound NMN, and some undergo fibrosis and in late stages may resemble dermatofibromas.
Synonyms: Pigmented and epithelioid spindle cell nevus. Years ago these were called “juvenile melanoma.”
Figure 9-9. Spitz nevus (A) Pink dome-shaped nodule on the cheek of a young woman, developing abruptly within the previous 12 months; the lesion can be mistaken for a hemangioma. (B) Pigmented Spitz nevus. A black papule surrounded by a tan macular region developed within a few months on the back of a young female; as such a lesion cannot be distinguished from a nodular melanoma, the lesion was excised and the diagnosis confirmed histologically.
Mongolian Spot ICD-9: 757.33 
These congenital gray-blue macular lesions are characteristically located on the lumbosacral area (Fig. 9-10) but can also occur on the back, scalp, or anywhere on the skin. There is usually a single lesion, but rarely, several truncal lesions can be present at birth (Fig. 9-11).
The underlying pathology is dispersed spindle-shaped melanocytes within the dermis (dermal melanocytosis). Melanocytes are not normally present in the dermis, and it is believed that these ectopic melanocytes represent pigment cells that have been interrupted in their migration from the neural crest to the epidermis.
Mongolian spots may disappear in early childhood, in contrast to nevus of Ota (see Fig. 9-12).
As the term Mongolian implies, these lesions are found almost always (99–100%) in infants of Asiatic and Native American origin; however, they have been reported in black and, rarely, in white infants.
No melanomas have been reported to occur in these lesions.
*In Asians.
Figure 9-10. Mongolian spot A large gray-blue macular lesion involving the entire lumbosacral and gluteal area and the left thigh in a baby from Sri Lanka. Although Mongolian spots are common in Asians, the parents of this baby were alarmed because the lesion was so large.
Figure 9-11. Mongolian spots Multiple, ill-defined, bluish lesions are scattered on the back of this Japanese child. They were present at birth. Most of these lesions disappeared later in childhood.
Nevus of Ota ICD-9: 216.9 ° ICD-10: D22 
Very common in Asian populations and is said to occur in 1% of dermatologic outpatients in Japan. It has been reported in East Indians, blacks, and, rarely, whites.
The pigmentation, which can be quite subtle or markedly disfiguring, consists of a mottled, dusky admixture of blue and brown hyperpigmentation of the skin. It mostly involves the skin and mucous membranes innervated by the first and second branches of the trigeminal nerve (Fig. 9-12).
The blue hue results from the presence of ectopic melanocytes in the dermis. It can occur in the hard palate and in the conjunctivae (Fig. 9-12), sclerae, and tympanic membranes.
Nevus of Ota may be bilateral (Fig. 9-12). It may be congenital but is not hereditary; more often it appears in early childhood or during puberty and remains for life, in contrast to the Mongolian spot, which may disappear in early childhood.
Treatment with lasers is an effective modality for this disfiguring disorder.
Malignant melanoma can occur but is rare.
*In Asians.
Figure 9-12. Nevus of Ota (A) There is an ill-defined, mottled, dusky, gray to bluish hyperpigmentation in the regions supplied by the first and second branches of the trigeminal nerve. The lesion was unilateral and there was also hyperpigmentation of the sclera and eyelids. (B). Bilateral nevus of Ota with involvement of the sclerae in a Japanese child.
Vascular Tumors and Malformations
The present binary biologic classification distinguishes between vascular tumors and vascular malformations. The latter are subclassified according to the structural components into capillary, venous, lymphatic, arterial, or combined forms (Table 9-1).
Vascular tumors (e.g., hemangiomas) show endothelial hyperplasia, whereas malformations have a normal endothelial turnover.
Hemangiomas of infancy are not present at birth but appear postnatally; grow rapidly during the first year (proliferating phase), undergo slow spontaneous regression during childhood (involution phase), and remain stable thereafter.
Vascular malformations are errors of morphogenesis and are presumed to occur during intrauterine life. Most are present at birth, though some do not appear until years later. Once manifested they grow proportionally, but enlargement can occur as a result of various factors.
Both vascular tumors and malformations can be separated into slow-flow or fast-flow types.
Classification of vascular tumors and malformations is shown in Table 9-1, and the distinguishing features of vascular tumors and vascular malformations are shown in Table 9-2.
TABLE 9-1 CLASSIFICATION OF VASCULAR ANOMALIES
TABLE 9-2 DISTINGUISHING FEATURES OF VASCULAR TUMORS (HEMANGIOMAS) AND VASCULAR MALFORMATIONS
Vascular Tumors
Hemangioma of Infancy (HI) ICD-9: 757,32 ° ICD-10: D18.0-M9131 
(Formerly strawberry, cherry, capillary hemangioma.)
Epidemiology
The most common tumor of infancy. Incidence in newborns between 1% and 2.5%; in white children by 1 year of age 10%. Females to males ratio is 3 to 1.
Etiology and Pathogenesis
HI is a localized proliferative process of angioblastic mesenchyme. A clonal expansion of endothelial cells resulting from somatic mutations of genes regulating endothelial cell proliferation.
Clinical Manifestation
The initial proliferative phase lasts from 3 to 9 months. His usually enlarge rapidly during the first year. In a subsequent phase of involution, the HI regresses gradually over 2–6 years. Involution is usually completed by the age of 10 and varies greatly between individuals. It is not correlated with size, location, or appearance of the lesion.
Skin Lesions. Soft, bright red to deep purple, compressible. On diascopy, does not blanch completely. Nodule or plaque, 1–8 cm (Figs. 9-13A and 9-14A). With the onset of spontaneous regression, a white-to-gray area appears on the surface of the central part of the lesion (Fig. 9-14A). Ulceration may occur.
Figure 9-13. Hemangioma of infancy (A) This bright red nodular plaque in an infant of African extraction is frightening to the parents, and caution is needed to prevent scarring from the treatment itself. Since most of these lesions disappear spontaneously with only 20% showing residual atrophy or depigmentation, a wait-and-see strategy is recommended. (B) The same lesion after 3 years. The hemangioma has faded spontaneously, and there is only slight residual atrophy.
Figure 9-14. Hemangioma of infancy (A) This lesion on the nose consists of a superficial and deep portion, and incipient involution is already apparent for the superficial compartment. Note an additional small hemangioma of infancy on the left zygomatic region. (B) By the fifth year, the hemangioma on the nose has almost disappeared and so has the lesion on the zygomatic region; the latter, however, that has left a small scar.
Distribution. Lesions are usually solitary and localized or extended over an entire region (Fig. 9-15). Head and neck 50% and trunk 25%. Face, trunk, legs, and oral mucous membrane.
Figure 9-15. Hemangioma of infancy Here it involves a large segment of skin. While involution is already apparent on the forehead, the lesion on the upper eyelid and the medial canthus is impairing proper function of the lid, and this indicates that vision might be impaired in the future. In this patient, treatment was indicated.
Special Presentations
Deep HI. (Formerly, cavernous hemangioma.) In the lower dermis and subcutaneous fat. Localized, firm rubbery mass of bluish or normal skin color with telangiectases in overlying skin (Fig. 9-16). Can be combined with superficial hemangioma (Fig. 9-14A). Does not involute as well as superficial type.
Figure 9-16. Hemangioma of infancy, deep lesion There is a rubbery mass in the subcutis associated with a superficial (red) portion. These lesions hardly regress. The hemangioma was removed by surgery.
Multiple His. Multiple small (<2 cm), cherry-red papular lesions involving skin alone (benign cutaneous hemangiomatosis) or skin and internal organs (diffuse neonatal hemangiomatosis).
Congenital Hemangiomas. These develop in utero and are subdivided into rapidly involuting congenital hemangiomas (RICH) and non-involuting congenital hemangiomas (NICH). They present as violaceous tumors with overlying telangiectasia with large veins in periphery or as red-violaceous plaques invading deeper tissues. NICH are fast-flow hemangiomas requiring surgery.
Laboratory Examination
Dermatopathology. Proliferation of endothelial cells in various amounts in the dermis and/or subcutaneous tissue; there is usually more endothelial proliferation in the superficial type and little in the deep angiomas. GLUT-1 immunoreactivity is found in all hemangiomas but not in vascular malformations.
Diagnosis
Made on clinical findings and MRI; Doppler and arteriography to demonstrate fast flow. Determine GLUT-1 immunoreactivity to rule out vascular malformation.
Course and Prognosis
HIs spontaneously involute by the fifth year, with some few percent disappearing only by age 10 (Figs. 9-13B and 9-14B). There is virtually no residual skin change at the site in most lesions (80%); in the rest there is atrophy, depigmentation, telangiectasia, and scarring. HIs may, however, pose a considerable problem during the growth phase when they interfere with vital functions, such as obstruction of vision (Fig. 9-15) or of larynx, nose, or mouth. Deeper lesions, especially those involving mucous membranes, may not involute completely. Synovial involvement may be associated with hemophilia-like arthropathy. Special forms of HI, tufted angiomas and Kaposiform hemangioendothelioma, may have platelet entrapment, thrombocytopenia (Kasabach–Merritt syndrome), and even disseminated intravascular coagulation. Rarely, morbidity associated with HI occurs secondary to hemorrhage or high-output heart failure.
Management
Each lesion must be judged individually regarding the decision to treat or not to treat and the selection of a treatment mode. Systemic treatment is difficult, requires experience, and should be performed by an expert. Surgical and medical interventions include continuous wave or pulsed dye laser, cryosurgery, intralesional and systemic high-dose glucocorticoids, interferon-α (IFN-α), and propranolol. For the majority of HIs, active nonintervention is the best approach because spontaneous resolution gives the best cosmetic results (Figs. 9-13B and 9-14B). Treatment is indicated in about a quarter of HIs (5% that ulcerate; 20% that obstruct vital structures, i.e., eyes, ears, larynx).
Pyogenic Granuloma ICD-9: 686.1 ° ICD-10: L98.0 
Pyogenic granuloma is a rapidly developing vascular lesion usually following minor trauma.
This is a very common solitary eroded vascular nodule that bleeds spontaneously or after minor trauma. The lesion has a smooth surface, with or without crusts and with or without erosion (Fig. 9-17A). It appears as a bright red, dusky red, violaceous, or brown-black papule with a collar of hyperplastic epidermis at the base (Fig. 9-17B) and occurs on the fingers, lips, mouth, trunk, and toes.
Histopathology: lobular aggregates of proliferating capillaries with edema and numerous neutrophils. Thus, pyogenic granuloma is neither pyogenic (associated with bacterial infection) nor a granuloma.
Treatment is surgical excision or curettage with electrodesiccation at the base.
The importance of pyogenic granuloma is that it can be mistaken for amelanotic nodular melanoma, and vice versa.
Figure 9-17. Pyogenic granuloma (A) This is a solitary vascular nodule of recent onset that bleeds spontaneously or after minor trauma. The lesions usually have a smooth surface, with or without crusts and with or without erosion. (B) On palms and soles, they have a typical collar of thickened stratum corneum at the base. This collar can best be seen when viewed from the side, as is the case here.
Glomus Tumor ICD-9: 228.0 ° ICD-10: M8711/0 
A tumor of the glomus body. This is an anatomic and functional unit composed of specialized smooth muscle and the glomus cells that surround thin-walled endothelial spaces; this anatomic unit functions as an arteriovenous shunt linking arterioles and venules. The glomus cells surround the narrow lumen of the Sucquet–Hoyer canal that branches from the arteriole and leads to the collecting venule segment that acts as a reservoir. Glomus bodies are present on the pads and nail beds of the fingers and toes and also on the volar aspect of hands and feet, in the skin of the ears, and in the center of the face.
The glomus tumor presents as an exquisitely tender subungual or subcutaneous papule or nodule. Glomus tumors are characterized by paroxysmal painful attacks, especially elicited by exposure to cold. They are most often present as solitary subungual tumors (Fig. 9-18A) but may rarely occur as multiple papules or nodules. These are noted, especially in children, as discrete papules or sometimes plaques anywhere on the skin surface (Fig. 9-18B).
Therapy is by excision.
Figure 9-18. Glomus tumor (A) This is an exquisitely painful subungual nodule of reddish color; pain becomes paroxysmal upon exposure to cold. (B) Glomus tumor on the palm of a 16-year-old boy.
Angiosarcoma* ICD-10: M9120/3 
A rare, highly malignant proliferation of endothelial cells manifesting as purpuric macules (Fig. 9-19A) and/or papules and nodules of bright red or violaceous and even black color (Fig. 9-19B). Nodules are solid, bleed easily, and ulcerate (Fig. 9-19C).
They occur in normal skin, usually on the scalp and upper forehead or in localized lymphedema, for instance, in postmastectomy lymphedema (Stewart-Treves syndrome) or postirradiation lymphedema (Fig. 9-19B).
Histologically: channels lined by pleomorphic endothelial cells with a high number of mitoses.
Treatment is by surgery and/or chemotherapy (liposomal doxorubicin). The 5-year survival is just above 10%.
*Angiosarcoma, although not a benign neoplasm, is discussed here because it fits with other vascular tumors.
Figure 9-19. Angiosarcoma (A) Early lesions appear as dusky erythematous macules. (B) More advanced lesions are red to black papules and nodules that bleed easily. (C) Advanced angiosarcoma with bleeding purple to black nodules, ulceration, and concomitant edema.
Vascular Malformations
These are malformations that do not undergo spontaneous involution.
Capillary malformations (CMs) (e.g., nevus flammeus, or port-wine stain (PWS), according to the old nomenclature), lymphatic malformation, capillary–lymphatic malformation (CLM), venous malformation (VM), and arteriovenous malformation (AVM) are distinguished.
Histologically they consist of enlarged, tortuous vessels of various types.
Only the most common and important are being dealt with here.
CAPILLARY MALFORMATIONS
Port-Wine Stain ICD-9: 757.32 ° ICD-10: Q82.5
A PWS is an irregularly shaped, red or violaceous, macular CM that is present at birth and never disappears spontaneously.
It is common (0.3% of newborns); the malformation is usually confined to the skin.
May be associated with vascular malformations in the eye and leptomeninges (Sturge–Weber syndrome [SWS]).
Synonym: Nevus flammeus.
Skin Lesions. Macular (Fig. 9-20) with varying hues of pink to purple. Large lesions follow a dermatomal distribution, usually unilateral (85%) though not always. Most commonly in the face, in the distribution of the trigeminal nerve (Fig. 9-20), and usually the superior and middle branches; mucosal involvement of conjunctiva and mouth may occur. CM may also involve other sites. With increasing age of the patient, papules or rubbery nodules (Fig. 9-21) cause significant disfigurement.
Figure 9-20. Port-wine stain Sharply marginated, port-wine red macule occurring in a distribution of the second branch of the trigeminal nerve in a child.
Clinical Variant
Nevus flammeus nuchae (“stork bite,” erythema nuchae, salmon patch) occurs in approximately one-third of infants on the nape of the neck and tends to regress spontaneously. Similar lesions may occur on eyelids and glabella. It is not really a CM but rather a transitory vasodilatation phenomenon.
Histopathology
Reveals ectasia of capillaries and no proliferation of endothelial cells. GLUT-1 immunoreactivity is negative.
Course and Prognosis
PWS are CMs that do not regress spontaneously. The area of involvement tends to increase in proportion to the size of the child. In adulthood, PWS usually become raised with papular and nodular areas and are the cause of significant progressive cosmetic disfigurement (Fig. 9-21).
Figure 9-21. Port-wine stain With increasing age, the color deepens and papular and nodular vascular lesions develop within the previously macular lesion, causing progressively increasing disfigurement.
Management
Treatment with tunable dye or copper vapor lasers is highly effective.
Syndromic CM
SWS is the association of PWS in the trigeminal distribution with vascular malformations in the eye and leptomeninges and superficial calcifications of the brain. May be associated with contralateral hemiparesis, muscular hemiatrophy, epilepsy, and mental retardation, and glaucoma and ocular palsy. Characteristic calcifications of vascular malformations or localized linear calcification along cerebral convolutions at x-ray. CT scan should be done. It should, however, be noted that PWS with trigeminal distribution is common and does not necessarily indicate the presence of SWS. Klippel–Trénaunay–Weber syndrome may have an associated PWS overlying the deeper vascular malformation of soft tissue and bone. PWS on the midline back may be associated with an underlying AVM of the spinal cord.
Spider Angioma ICD-9: 448.1 ° ICD-10:178.1
A very common red focal telangiectatic network of dilated capillaries radiating from a central arteriole (punctum) (Fig. 9-22A). The central papular punctum is the site of the feeding arteriole with macular radiating telangiectatic vessels. Up to 1.5 cm in diameter. Usually solitary.
On diascopy, the radiating telangiectasia blanches and the central arteriole may pulsate.
Most commonly occurs on the face, forearms, and hands.
It frequently occurs in normal persons and is more common in females; occurs in children.
It may be associated with hyperestrogenic states, such as pregnancy (one or more in two-thirds of pregnant women), in patients receiving estrogen therapy, e.g., oral contraceptives, or in those with hepatocellular disease such as subacute and chronic viral hepatitis and alcoholic cirrhosis (Fig. 9-22B).
Spider angioma arising in childhood and pregnancy may regress spontaneously.
The lesion may be confused with hereditary hemorrhagic telangiectasia, ataxia-telangiectasia, or telangiectasia in systemic scleroderma.
Lesions may be treated easily with electro- or laser surgery.
Synonyms: Nevus araneus, spider nevus, arterial spider, spider telangiectasia, vascular spider.
Figure 9-22. Spider nevus (A) Two small papules from which telangiectasias radiate. Upon compression the lesion blanches completely. (B) Spider nevi on the chest of a patient with cirrhosis.
Venous Lake ICD-9: 528.5 ° ICD-10: K13.0
A venous lake is a dark blue to violaceous, asymptomatic, soft papule resulting from a dilated venule, occurring on the face, lips, and ears of patients >50 years of age (Fig. 9-23A and B).
Etiology unknown, but it has been related to solar exposure.
Lesions are few in number and remain for years. A dilated cavity is lined with a single layer of flattened endothelial cells filled with red blood cells and surrounded by a thin wall of fibrous tissue.
Because of its dark blue or sometimes even black color, the lesion may be confused with nodular melanoma, pigmented BCC, or pyogenic granuloma.
The lesion can be partially compressed and lightened up by diascopy, and the use of dermoscopy permits its diagnosis as a vascular lesion.
Management is for cosmetic reasons and can be accomplished with electrosurgery, laser, or, rarely, with surgical excision.
Figure 9-23. Venous lake (A) On the cheek of a 70-year-old male. The lesion was almost black and became a matter of concern to the patient, who feared he might have melanoma. However, it blanched completely after compression. (B) Venous lake on the auricle of a 75-year-old male. The lesion is dark bluish-red and smooth resembling a basal cell carcinoma. It blanched upon compression.
Cherry Angioma ICD-9: 228,0·ICD-10:178.8
Cherry angiomas are exceedingly common, asymptomatic, bright red to violaceous or even black, domed vascular lesions (~3 mm) (Fig. 9-24), or occurring as myriads of tiny red papular spots simulating petechiae.
They are found principally on the trunk. The lesions appear first at about age 30 and increase in number over the years.
Almost all elderly people have a few lesions.
The histology consists of numerous moderately dilated capillaries lined by flattened endothelial cells; stroma is edematous with homogenization of collagen.
They are of no consequence other than their cosmetic appearance. Management is electro-or laser coagulation if indicated cosmetically. Cryosurgery is not effective.
Synonyms: Campbell de Morgan spots, senile (hem)angioma.
Figure 9-24. Cherry angiomas These bright red, violaceous, or even black lesions appear progressively on the trunk with advancing age.
Angiokeratoma ICD-9: 448.9 ° ICD-10: M9141/0 
The term angio (“blood vessel”) keratoma would imply a vascular tumor with keratotic elements. But, in fact, capillaries and postcapillary venules are packed into the papillary body just beneath and bulging into the epidermis, leading to hyperkeratosis. This and the fact that the lumina are usually at least partially thrombosed impart a firm consistency to the lesions.
Angiokeratomas are dark violaceous to black, often keratotic papules or small plaques that are hard upon palpation and cannot be compressed by diascopy (Fig. 9-25).
Angiokeratoma can appear as a solitary lesion (solitary angiokeratoma), and then the most important differential diagnosis is a small nodular or superficial spreading melanoma (Fig. 9-25).
The most common is angiokeratoma of Fordyce; this disease involves the scrotum and vulva; the lesions are multiple papules (<4 mm) that are dark red in color and present in quite large numbers (Fig. 9-26).
Angiokeratoma of Mibelli comprises pink to dark red and even black papules that occur on the elbows, knees, and dorsa of the hands. This autosomal-dominant disease is rare and occurs in young females.
Angiokeratoma corporis diffusum (Fabry disease), an X-linked recessive disease, is an inborn error of metabolism in which there is a deficiency of α-galactosidase A leading to an accumulation of neutral glycosphingolipid ceramide trihexoside in endothelial cells, fibrocytes, and pericytes in the dermis, heart, kidneys, and autonomic nervous system. Lesions are numerous dark red, punctate, and tiny (<1 mm) (Fig. 9-27), located on the lower half of the body: lower abdomen, genitalia, and buttocks, although lesions may also occur on the lips. The homozygous males have also symptoms related to involvement of other organ systems: acroparesthesias, excruciating pain, transient ischemic attacks, and myocardial infarction. Heterozygous females may have corneal opacities. Fabry disease is very rare but serious.
*Fabry disease.
Figure 9-25. Angiokeratoma: solitary This black, firm lesion with a pebbled surface immediately sparks the suspicion of superficial spreading melanoma. It is noncompressible, but dermoscopy reveals the typical lacunae of thrombosed vascular spaces. Nonetheless, such lesions should be excised.
Figure 9-26. Angiokeratoma of fordyce Reddish, violaceous, and black papules on the scrotum. They blanch upon diascopy and this verifies the diagnosis. Note: Thrombosed angiokeratomas do not blanch.
Figure 9-27. Angiokeratoma corporis diffusum (Fabry disease) Numerous red, punctate lesions on the lower flank.
LYMPHATIC MALFORMATION
“Lymphangioma” ICD-9: 228,1 ° ICD-10: D18,1 -M9170/0 
The term LYM is now the terminology for what was formerly called “lymphangioma.”
These typical lesions comprise multiple, grouped, small macroscopic vesicles filled with clear or serosanguineous fluid (“frog-spawn”) (Fig. 9-28). However, these are not true vesicles but microcystic lesions (lymphangioma) as opposed to a macrocystic lesion (cystic hygroma), which is located deep in the dermis and subcutis and appears as a large soft subcutaneous tumor often distorting the face or an extremity.
The microcystic LYM is present at birth or appears in infancy or childhood. It may disappear spontaneously, but this is extremely rare. Bacterial infection may occur.
LYM may occur as an isolated solitary lesion, as in Fig. 9-28, or cover large areas (up to 10 × 20 cm); it may be associated with a capillary venous lymphatic (CVL) malformation.
The lesion can be excised, if feasible, or treated with sclerotherapy.
Figure 9-28. Lymphatic malformation (lymphangioma) Frog-spawn–like confluent grouped “vesicles” filled with a serosanguineous fluid.
Capillary/Venous Malformations (CVMs) ICD-9: 757.32 
CVMs are deep vascular malformations characterized by soft, compressible deep-tissue swelling. Lesions are not apparent at birth but become so during childhood.
They manifest as soft-tissue swelling, dome-shaped or multinodular (Fig. 9-29), and are slow-flow lesions. When vascular malformation extends to the epidermis, the surface may be verrucous. Borders are poorly defined, and there is considerable variation in size. Often, CVMs are normal skin color, with the nodular portion blue to purple. They are easily compressed and fill promptly when pressure is released. Some types may be tender, and they may be associated with CMs.
CVMs may be complicated by ulceration and bleeding, scarring, and secondary infection; and, with large lesions, by high-output heart failure.
CVMs may interfere with food intake or breathing and, if located on the eyelids or in the vicinity of the eyes, will obstruct vision and may lead to blindness.
There is no satisfactory treatment except compression. In larger lesions—if organ function is compromised—surgical procedures and intravascular coagulation should be performed. High-dose systemic glucocorticoids or IFN-α or propranolol may be effective.
Figure 9-29. Capillary–venous malformation In an infant. There is a soft, compressible, bluish-red tissue swelling distorting the upper lip and lower eyelid. It is a slow-flow lesion but requires therapeutic intervention.
Variants
Vascular Hamartomas. CVLs with deep soft-tissue involvement and resultant swelling or diffuse enlargement of an extremity. May involve skeletal muscle with muscle atrophy. Cutaneous changes include dilated tortuous veins and arteriovenous fistulas.
Klippel–Trénaunay Syndrome. A CVM or CVL malformation, slow-flow lesion. Local overgrowth of soft tissue and bone results in enlargement of an extremity. Associated cutaneous changes include phlebectasia, nevus flammeus-like cutaneous CM (Fig. 9-30), lymphatic hypoplasia, and lymphedema.
Figure 9-30. Capillary–venous malformation In a 31-year-old Thai woman. This nevus flammeus-like lesion was associated with phlebectasia, lymphedema, and an enlarged right lower extremity (Klippel–Trénaunay syndrome).
Blue Rubber Bleb Nevus. A CVM, spontaneously painful and/or tender. A compressible, soft, blue swelling in the dermis and subcutaneous tissue. Size ranges from a few millimeters to several centimeters (Fig. 9-31). May exhibit localized hyperhidrosis over CVM malformations and occurs, often multiply, on the trunk and upper arms. Similar vascular lesions can occur in the gastrointestinal tract and may be a source of hemorrhage.
Figure 9-31. Blue rubber bleb nevus A spontaneously painful and tender capillary-venous malformation. There are a number of compressible bluish-violaceous papules and nodules on the upper arm.
Maffucci Syndrome. A slow-flow venous or lymphatic/venous malformation associated with enchondromas and manifested as hard nodules on fingers or toes and as bony deformities. Patients may develop chondrosarcoma.
Parkes Weber Syndrome. A fast-flow capillary arteriovenous malformation (CAVM) or CM, with soft tissue and skeletal hypertrophy.
MISCELLANEOUS CYSTS AND PSEUDOCYSTS
Epidermoid Cyst ICD-9: 706.2 ° ICD-10: L72.0
An epidermoid cyst is the most common cutaneous cyst, derived from epidermis or the epithelium of the hair follicle, and is formed by cystic enclosure of epithelium within the dermis that becomes filled with keratin and lipid-rich debris.
It occurs in young to middle-aged adults on the face, neck, upper trunk, and scrotum.
The lesion, which is usually solitary but may be multiple, is a dermal-to-subcutaneous nodule, 0.5–5 cm, which often connects with the surface by keratin-filled pores (Fig. 9-32).
The cyst has an epidermal-like wall (stratified squamous epithelium with well-formed granular layer); the content of the cyst is keratinaceous material—cream-colored with a pasty consistency and the odor of rancid cheese. Scrotal lesions may calcify.
The cyst wall is relatively thin. Following rupture of the wall, the irritating cyst contents initiate an inflammatory reaction, enlarging the lesion manifold; the lesion is now associated with a great deal of pain. Ruptured cysts are often misdiagnosed as being infected rather than ruptured.
Synonyms: Wen, sebaceous cyst, infundibular cyst, epidermal cyst.
Figure 9-32. Epidermoid cyst A rounded nodule within the dermis with an opening (which is not always visible) in which caseous keratinous material can be expressed.
Trichilemmal Cyst ICD-9: 706.2 ° ICD-10: L72.0
A trichilemmal cyst is the second most common type of cutaneous cyst and is seen most often in middle age, more frequently in females. It is often familial and occurs frequently as multiple lesions.
These are smooth, firm, dome-shaped, 0.5- to 5-cm nodules or tumors; they lack the central punctum seen in epidermoid cysts. They are not connected to the epidermis.
Over 90% occur on the scalp, and the overlying scalp hair is usually normal but may be thinned if the cyst is large (Fig. 9-33).
The cyst wall is usually thick, and the cyst can be removed intact. The wall is a stratified squamous epithelium with a palisaded outer layer resembling that of the outer root sheath of hair follicles. The inner layer is corrugated without a granular layer.
The cyst contains keratin—very dense, homogeneous; it is often calcified, with cholesterol clefts. If cyst ruptures, it may be inflamed and very painful.
Synonyms: Pilar cyst, isthmus catagen cyst. Archaic terms: Wen, sebaceous cyst.
Figure 9-33. Trichilemmal cyst A firm, dome-shaped nodule on the scalp. Pressure by the cyst has caused atrophy of hair bulbs, and it thus appears without hairs.
Epidermal Inclusion Cyst ICD-9: 706.2 ° ICD-10: L72.01 
An epidermal inclusion cyst occurs secondary to traumatic implantation of epidermis into the dermis. Traumatically grafted epidermis grows in the dermis, with accumulation of keratin within the cyst cavity, enclosed in a stratified squamous epithelium with a well-formed granular layer.
The lesion appears as a dermal nodule (Fig. 9-34) and most commonly occurs on the palms, soles, and fingers.
It should be excised.
Synonym: Traumatic epidermoid cyst.
Figure 9-34. Epidermal inclusion cyst A small dermal nodule on the knee at the site of the laceration.
Milium ICD-9: 706.2 °ICD-10:L72.83
A milium is a 1- to 2-mm, superficial, white to yellow, keratin-containing epidermal cyst, occurring multiply, located on the eyelids, cheeks, and forehead in pilosebaceous follicles (Fig. 9-35A, B).
The lesions can occur at any age, even in infants.
Milia arise either de novo, especially around the eye, or in association with various dermatoses with subepidermal bullae or vesicles (pemphigoid, porphyria cutanea tarda, bullous lichen planus, epidermolysis bullosa) (Fig. 9-35C) and skin trauma (abrasion, burns, dermabrasion, radiation therapy).
Incision and expression of contents are the method of treatment.
Figure 9-35. Milia (A) A small chalk-white or yellowish papule on the cheek; it can be slit with a scalpel, releasing a little ball of horny material. (B). A larger lesion on the lower lid of an African woman. (C) Multiple milia on the trunk of a child with hereditary dystrophic epidermolysis bullosa (see Section 6).
Digital Myxoid Cyst ICD-9: 727.41 ° ICD-10: M25.8 
A digital myxoid cyst is a pseudocyst occurring over the distal interphalangeal joint and the base of the nail of the finger (Fig. 9-36A) or toe, often associated with Heberden’s (osteophytic) node.
The lesion occurs in older patients, usually >60 years of age.
It is usually a solitary cyst, rubbery, translucent. A clear gelatinous viscous fluid may be expressed (Fig. 9-36B).
When the myxoid cyst is over the nail matrix, a nail plate dystrophy occurs in the form of a 1- to 2-mm groove that extends to the length of the nail (Figs. 9-36A; see also Fig. 34-13.
Various methods of management have been advocated, including surgical excision, incision and drainage, injection of sclerosing material, and injection of a triamcinolone suspension. A simple and most effective method is to make a small incision, express the gelatinous contents, and use a firm compression bandage over the lesion over a period of weeks.
Synonyms: Mucous cyst, synovial cyst, myxoid pseudocyst.
Figure 9-36. Digital myxoid cyst (A) The cyst has led to a 3- to 4-mm groove of the nail plate. (B) Slitting it with a scalpel and pressure releases a gelatinous viscous fluid.
Miscellaneous Benign Neoplasms and Hyperplasias
Seborrheic Keratosis ICD-9: 702.1 ° ICD-10: L82
The seborrheic keratosis is the most common of the benign epithelial tumors.
These lesions, which are hereditary, do not appear until age 30 and continue to occur over a lifetime, varying in extent from a few scattered lesions to literally hundreds in some very elderly patients.
Lesions range from small, barely elevated papules to plaques with a warty surface and a “stuck on” appearance.
Lesions are benign and do not require treatment except for cosmetic reasons. They can become irritated or traumatized, with pain and bleeding. SCC should be ruled out.
Synonym: verruca seborrhoica.
Epidemiology
Onset. Rarely before 30 years.
Sex. Slightly more common and more extensive involvement in males.
Clinical Manifestation
Evolve over months to years. Rarely pruritic; tender if secondarily infected.
Skin Lesions. Early. Small, 1- to 3-mm, barely elevated papule, later a larger plaque (Figs. 9-37 and 9-38) with or without pigment. The surface has a greasy feel and often shows, with a hand lens, fine stippling like the surface of a thimble. Late. Plaque with warty surface and “stuck on” appearance (Fig. 9-39), “greasy.” With a hand lens horn cysts can often be seen; with dermoscopy they can always be seen and are diagnostic. Size from 1 to 6 cm. Flat nodule. Brown, gray, black, skin-colored, round or oval (Figs. 9-38 and 9-39A,B).
Figure 9-37. Seborrheic keratosis, solitary A slightly raised, keratotic, brown, flat plaque on the zygomatic region in an older female. The differential diagnosis includes lentigo maligna and lentigo maligna melanoma.
Figure 9-38. Seborrheic keratosis (dermatosis papulosa nigra) This consists of a myriad of tiny black lesions, some enlarging to more than a centimeter. This is seen in Black Africans, African Americans, and deeply pigmented South East Asians.
Figure 9-39. Seborrheic keratosis (A) Small, heavily pigmented seborrheic keratoses can have a smooth surface and present a differential diagnostic challenge: pigmented basal cell carcinoma and nodular melanoma have to be excluded. (B) Large seborrheic keratoses have a “stuck on” appearance and can be very dark and irregular. Because of their multiplicity, they usually do not present a diagnostic problem. As shown here, they can be disfiguring.
Distribution. Isolated lesion or generalized. Face, trunk (Fig. 9-40), upper extremities. In females, commonly occur in submammary intertriginous skin. In dark-skinned people, multiple, small black lesions in the face are called dermatosis papulosa nigra (Fig. 9-38). When numerous and dense, SKs may become confluent.
Figure 9-40. Seborrheic keratoses, multiple Multiple brown, warty papules and nodules on the back, having a “greasy” feel and “stuck on” appearance. This picture also shows the evolution of the lesions: from small only slightly tan, very thin papules, or plaques to larger, darker nodular lesions with a verrucous surface. Practically all lesions on the back of this elderly patient are seborrheic keratoses; what they have in common is that they give the impression that they could be scraped off easily, which, in fact, they can.
Laboratory Examination
Dermatopathology. Proliferation of monomorphous keratinocytes (with marked papillomatosis) and melanocytes, and formation of horn cysts.
Diagnosis and Differential Diagnosis
Clinically, the diagnosis is made easily. “Tan Macules”. Early “flat” lesions may be confused with solar lentigo or spreading pigmented actinic keratosis (see Figs. 10-22 and 10-28). Skin-Colored/Tan/Black Verrucous Papules/Plaques. Larger pigmented lesions are easily mistaken for pigmented BCC or malignant melanoma (Fig. 9-39) (only biopsy will settle this, or dermoscopy will be of assistance); verruca vulgaris may be similar in clinical appearance, but thrombosed capillaries are present in verrucae.
Course and Prognosis
Lesions develop with increasing age; they are benign and do not become malignant.
Management
Light electrocautery permits the whole lesion to be easily rubbed off. This, however, precludes histopathologic verification of diagnosis and should be done only by an experienced diagnostician. Cryosurgery with liquid nitrogen spray works only in flat lesions, and recurrences are possibly more frequent. The best approach is curettage after slight freezing with cryospray, which also permits histopathologic examination.
Becker Nevus (BN) ICD-9: 216 ° ICD-10: M8720/0
BN is a distinctive asymptomatic clinical lesion that is a pigmented hamartoma—i.e., a developmental anomaly consisting of changes in pigmentation, hair growth, and a slightly elevated smooth verrucous surface (Fig. 9-41).
It occurs mostly in males and in all races. It appears not at birth but usually before 15 years of age and sometimes after this age.
The lesion is predominantly a macule but with a papular verrucous surface not unlike the lesion of acanthosis nigricans. It is light brown in color and has a geographic pattern with sharply demarcated borders (Fig. 9-41A).
Commonest locations are the shoulders and the back. The increased hair growth follows the onset of the pigmentation and is localized to the areas that are pigmented (Fig. 9-41B). The pigmentation is related to increased melanin in basal cells and not to an increased number of melanocytes.
It is differentiated from a hairy congenital melanocytic nevus, because BN is not usually present at birth, and from café au lait macules because these are not hairy.
The lesion extends for a year or two and then remains stable, only rarely fading.
There is very rarely hypoplasia of underlying structures, e.g., shortening of the arm or reduced breast development in areas under the lesion.
Management: the hypertrichosis can be of cosmetic concern to some individuals.
Figure 9-41. A and B Becker nevus (A) A slightly raised light-tan plaque with sharply defined and highly irregular border and slight hypertrichosis on the chest of a 16-year-old male patient. (B) In this case of Becker nevus, the massive hypertrichosis conceals the tan background plaque.
Trichoepithelioma ICD-9: M8100/0 ICD-10: D23
Trichoepitheliomas are benign appendage tumors with hair bulb differentiation.
The lesions, which appear at puberty, occur on the face (Fig. 9-42) and less often on the scalp, neck, and upper trunk.
Lesions may be only a few small pink or skin-colored papules. They gradually increase in number and can be confused with BCC (Fig. 9-42A).
Trichoepitheliomas can also appear as solitary tumors, which may be nodular (Fig. 9-42B), or appear as ill-defined plaques like sclerosing BCC.
Figure 9-42. Trichoepitheliomas (A) Multiple, small, sharply defined smooth papules that look like early BCCs. (B) Trichoepithelioma, solitary type. A nodular tumor on the upper lip that can be confused with a basal carcinoma or squamous cell carcinoma.
Syringoma ICD-9: 216.0-216.9 ° ICD-10: D23-M8407/0
Syringomas are benign adenomas of the eccrine ducts. They are 1- to 2-mm, skin-colored or yellow, firm papules that occur mostly in women, beginning at puberty; they may be familial.
Most often multiple rather than solitary, they occur most frequently on lower periorbital area, usually symmetrically but also on the eyelids (Fig. 9-43) and on the face, axillae, umbilicus, upper chest, and vulva.
The lesions have a specific histologic pattern: many small ducts in the dermis with comma-like tails with the appearance of “tadpoles.”
The lesions can be disfiguring, and most patients want them removed; this can be done easily with electrosurgery.
Figure 9-43. Syringomas Symmetric eruption of 1- to 2-mm skin-colored, smooth papules on the upper and lower eyelids.
Sebaceous Hyperplasia ICD-9: 706.9
These are very common lesions in older persons and are confused with small BCCs. Also occurs in solid organ transplant recipients treated with cyclosporine. The lesions are 1–3 mm in diameter and have both telangiectasia and central umbilication (Fig. 9-44).
Two features distinguish sebaceous hyperplasia from nodular BCC: (1) sebaceous hyperplasia is soft to palpation, not firm as in nodular BCC; and (2) with firm lateral compression, it is often possible to elicit a very small globule of sebum in the valley of the umbilicated portion of the lesion.
Sebaceous hyperplasias can be destroyed with light electrocautery.
Figure 9-44. Sebaceous hyperplasia 1- to 4-mm smooth papules on the cheek of a 65-year-old man. They look like small basal cell carcinomas but have a central umbilication.
Nevus Sebaceous ICD-9: 216.3
This congenital malformation of sebaceous differentiation occurs on the scalp or, rarely, on the face (Fig. 9-45).
A hairless, thin, elevated, 1- to 2-cm plaque, sometimes larger, with a characteristic orange color and a pebbly or warty surface.
About 10% of patients can be expected to develop BCC in the lesion.
Excision is recommended at around puberty for cosmetic reasons and to prevent the occurrence of BCC.
Synonym: Organoid nevus.
Epidermal Nevus ICD-9: 216
A developmental (hamartomatous) disorder characterized by hyperplasia of epidermal structures (epidermis and adnexa). There are no nevomelanocytic nevus cells.
Usually present at birth or occurs in infancy; rarely, it develops in puberty. All epidermal nevi on the head/neck region are present at birth.
Several variants: The verrucous epidermal nevus may be localized or multiple. Lesions are skin-colored, brown, or grayish-brown (Fig. 9-46) and are composed of closely set verrucous papules, well circumscribed; they are often in a linear arrangement—especially on the leg—or they may appear in Blaschko lines on the trunk. Excision is the best treatment, if feasible.
When the lesions are extensive, they are termed systematized epidermal nevus, and when they are located on half the body, they are termed nevus unius lateris.
Linear lesions can exhibit erythema, scaling, and crusting and are then called inflammatory linear verrucous epidermal nevus (ILVEN). The lesions gradually enlarge and become stable in adolescence.
There is also a noninflammatory linear verrucous epidermal nevus (NILVEN).
Extensive epidermal nevi (epidermal nevus syndrome) may be multisystem disorders and may be associated with developmental abnormalities (bone cysts, hyperplasia of bone, scoliosis, spina bifida, kyphosis), vitamin D-resistant rickets, and neurologic problems (mental retardation, seizures, cortical atrophy, hydrocephalus). These patients require a complete examination, including the eyes (cataracts, optic nerve hypoplasia), and cardiac studies to rule out aneurysms or patent ductus arteriosus.
Figure 9-45. Nevus sebaceous In a baby an elevated plaque of orange color and pebbly surface. Note that the lesion is hairless on the scalp.
Figure 9-46. Epidermal nevus A grayish irregular plaque with a verrucous surface on the ear extending linearly down to the neck.
Benign Dermal and Subcutaneous Neoplasms and Hyperplasias
Lipoma ICD-9: 214 ° ICD-10: D17-M8850/0
Lipomas are single or multiple, benign subcutaneous tumors that are easily recognized because they are soft, rounded, or lobulated and movable against the overlying skin (Fig. 9-47).
Many lipomas are small but may also enlarge to >6cm.
They occur mostly on the neck, trunk, and on the extremities (Fig. 9-47) but can occur anywhere on the body.
Lipomas are composed of fat cells that have the same morphology as normal fat cells within a connective tissue framework. Angiolipomas have a vascular component and may be tender in cold ambient temperature and with compression.
Angiolipomas often require excision, whereas other lipomas should be excised only when considered disfiguring. Liposuction can also be performed when liposomas are soft and thus have only a minor connective tissue component.
Familial lipoma syndrome, an autosomal-dominant trait appearing in early adulthood, consists of hundreds of slowly growing nontender lesions.
Adipositas dolorosa, or Dercum disease, occurs in women in middle age; there are multiple tender, not circumscribed but rather diffuse fatty deposits.
Benign symmetric lipomatosis, which affects middle-aged men, consists of many large nontender, coalescent poorly circumscribed lipomas, mostly on the trunk and upper extremities; they coalesce on the neck and may lead to a “horse-collar” appearance.
Figure 9-47. Lipoma (A) Well-defined, soft, rounded tumors in the subcutis, movable both against the overlying skin and the underlying structures, in a 56-year-old male patient. In this patient, lesions were symmetric and were also found on the trunk and upper extremities. (B) Solitary lipoma on the lower arm of a 50-year-old patient.
Dermatofibroma ICD-9: 216 ° ICD-10: D23-M8832/0
A dermatofibroma is a very common, button-like dermal nodule, usually occurring on the extremities.
Important only because of its cosmetic appearance or its being mistaken for other lesions, such as malignant melanoma when it is pigmented.
Considered to represent late histiocytic reaction to an arthropod bite.
Asymptomatic nodule (Fig. 9-48), 3–10 mm in diameter, domed but also sometimes depressed below surrounding skin. Surface dull, shiny or scaly. Firm, color viarable—skin-colored, pink (Fig. 9-48A), brown or dark chocolate brown (Fig. 9-48B); borders ill defined. Dimple sign: lateral compression produces a “dimple” sign (Fig. 9-48C).
Rarely may be tender.
Appears gradually over several months and persists without further increase in size for years—may regress spontaneously.
Treatment not necessary. Excision produces scar, cryosurgery with cotton tip applicator usually has to be repeated and produces a cosmetically more acceptable scar.
Synonyms: Solitary histiocytoma, sclerosing hemangioma.
Figure 9-48. Dermatofibroma (A) A dome-shaped, slightly erythematous and tan nodule with a button-like, firm consistency. (B) This lesion is pigmented. Can be confused with blue nevus or even nodular melanoma. The pigment is melanin and hemosiderin. (C) “Dimple sign.” Dimpling of the lesion is seen when pinched between two fingers.
Hypertrophic Scars and Keloids ICD-9:701.4 ° ICD-10: L91.0 
Hypertrophic scars and keloids are exuberant fibrous repair tissues after a cutaneous injury.
A hypertrophic scar remains confined to the site of original injury.
A keloid, however, extends beyond this site, often with clawlike extensions.
May be cosmetically very unsightly and pose a serious problem for the patient if the lesion is large and on the ear or face or over a joint.
Epidemiology and Etiology
Age of Onset. Third decade, but all ages.
Sex. Equal incidence in males and females.
Race. Much more common in blacks and in persons with blood group A.
Etiology. Unknown. They usually follow injury to skin, i.e., surgical scar, laceration, abrasion, cryosurgery, and electrocoagulation as well as vaccination, acne, etc. Keloid may also arise spontaneously, without history of injury, usually in presternal site.
Clinical Manifestation
Skin Symptoms. Usually asymptomatic. May be pruritic or painful if touched.
Skin Lesions. Papules to nodules (Fig. 9-49) to large tuberous lesions. Most often the color of the normal skin but also bright red or bluish. May be linear after traumatic or surgical injury (Fig. 9-49A) oval or round (Fig. 9-49B). Hypertrophic scars tend to be elevated and are confined to approximately the site of the original injury (Fig. 9-49). Keloids, however, may be nodular (Fig. 9-50) or extend in a clawlike fashion far beyond the original injury (Fig. 9-51A). Firm to hard; may be tender, surface smooth. Spontaneous keloids arise de novo without trauma or surgery, and usually occur on the chest (Fig. 9-51IB).
Figure 9-49. Hypertrophic scar (A) A broad, raised scar developing at the site of surgical incision with telangiectatic blood vessels and a shiny atrophic epidermis. (B) Multiple hypertrophic scars on the chest of a 22-year-old male with a history of severe cystic acne.
Figure 9-50. Keloids Well-defined irregular nodules, very hard on palpation, in the auricular region, and cheek of a 30-year-old man. The lesions on the earlobe arose after piercing and the lesion on the mandibular region after incision of an inflamed cyst.
Figure 9-51. Keloids (A) Keloid after a deep burn. Note sausage- and clawlike extensions of the keloid into normal skin. (B) Spontaneous keloids that arose without apparent cause on the chest of a 19-year-old man.
Distribution. Earlobes, shoulders, upper back, chest.
Laboratory Examination
Dermatopathology. Hypertrophic Scar. Whorls of young fibrous tissue and fibroblasts in haphazard arrangement.
Keloid. Features of hypertrophic scar with added feature of thick, eosinophilic, acellular bands of collagen.
Diagnosis and Differential Diagnosis
Clinical diagnosis; biopsy not warranted unless there is clinical doubt, because this may induce new hypertrophic scarring. Differential diagnosis includes dermatofibroma, dermatofibrosarcoma protuberans, desmoid tumor, scar with sarcoidosis, and foreign-body granuloma.
Course and Prognosis
Hypertrophic scars tend to regress, in time becoming flatter and softer. Keloids, however, may continue to expand in size for decades.
Management
This is a real challenge, as no treatment is highly effective.
Intralesional Glucocorticoids. Intralesional injection of triamcinolone (10–20 mg/mL) every month may reduce pruritus or sensitivity of lesion, as well as reduce its volume and flatten it. Works quite well in small hypertrophic scars but less well in keloids.
Surgical Excision. Lesions that are excised surgically often recur larger than the original lesion. Excision with immediate postsurgical radiotherapy is beneficial.
Silicone Cream and Silicone Gel Sheet. Reported to be beneficial in keloids and is painless and noninvasive. Not very effective in authors’ experience.
Prevention. Individuals prone to hypertrophic scars or keloids should be advised to avoid cosmetic procedures such as ear piercing. Scars from burns tend to become hypertrophic. Can be prevented by compression garments.
Infantile Digital Fibromatosis ICD-9: 757.3 ° ICD-10: M72
A rare form of superficial juvenile fibromatosis.
Presenting as asymptomatic flesh-colored or pink firm nodule on fingers and toes (Fig. 9-52).
Appears in the first year of life, less commonly in childhood.
Histologically interlacing bundles of myofibroblasts with eosinophilic inclusions.
Benign. Spontaneous regression is rare. Treatment is surgical
Synonym: Rye tumor.
Figure 9-52. Infantile digital fibromatosis A well-defined pink nodule on the finger of an infant. Usually the third to fifth digits are affected. Here, the tumor is found on the second digit.
Skin Tag ICD-9: 701.9 ° ICD-10: L91.8
A skin tag is a very common, soft, skin-colored or tan or brown, round or oval, pedunculated papilloma (polyp) (Fig. 9-53); it is usually constricted at the base and may vary in size from >1 mm to as large as 10 mm. Occurring in the middle aged and elderly.
Histologic findings include a thinned epidermis and a loose fibrous tissue stroma.
Usually asymptomatic but occasionally may become tender following trauma or torsion and may become crusted or hemorrhagic.
More common in females and in obese patients and most often noted in intertriginous areas (axillae, inframammary, groin) and on the neck and eyelids.
It occurs in acanthosis nigricans and metabolic syndrome.
May be confused with a pedunculated seborrheic keratosis, dermal or compound melanocytic nevus, solitary neurofibroma, or molluscum contagiosum.
Lesions tend to become larger and more numerous over time, especially during pregnancy. Following spontaneous torsion, autoamputation can occur.
Management is accomplished with simple snipping with scissors, electrodesiccation, or cryosurgery.
Synonyms: Acrochordon, cutaneous papilloma, soft fibroma.
Figure 9-53. Skin tags Soft skin-colored and tan pedunculated papillomas. These are very common in the elderly obese and are obligatory lesions in acanthosis nigricans, as in this patient.