Atlas of Mammography

Chapter 5

Indistinct and Spiculated Masses

A poorly defined mass on mammography is a primary sign of breast carcinoma. The majority of breast carcinomas have an infiltrative, irregular appearance with spiculation (1). A variety of benign lesions, including fibrocystic changes (fibrosis, cysts, hyperplasia), radial scars, fat necrosis, hematomas, abscesses, and scars may also present as poorly defined masses radiographically. In addition to the mammographic findings, clinical history and physical examination may be of help in differentiating these lesions. However, in many cases, biopsy is necessary to confirm the etiology of a poorly defined mammographic lesion.

The BI-RADS® Lexicon (2) defines mass shapes as round, oval, lobular, and irregular and mass margins as circumscribed, obscured, microlobulated, indistinct, and spiculated. Indistinct masses are those in which a lesion or portion of the margin is fuzzy or poorly defined (Fig. 5.1). The shape of an indistinct mass may be any of those listed above. The importance of identifying an indistinctly marginated mass is that biopsy is necessary unless the mass represents a postsurgical finding. A spiculated mass (Fig. 5.2) has a margin that is composed of fine tendrils that surround the lesion. This pattern is highly suggestive of malignancy unless it represents a postsurgical scar. Therefore, history and clinical examination confirming the location of the scar are key to suggesting the correct diagnosis.

It is important to determine that an ill-defined lesion can be identified on two projections and is a true mass. Overlying glandular tissue can be visualized on one projection as an irregular density but on the orthogonal view is seen to disperse. If a density has a similar configuration on two projections, more complete evaluation is necessary. Spot-compression views of the lesion may be of help in evaluating its central density and in displacing the surrounding glandular tissue. The presence of a radiolucent center within a poorly defined density suggests a fibrocystic process as a likely etiology (3) or a radial scar, but it is not confirmatory. Ultrasound is also helpful in the assessment of a poorly defined mass. In particular, if a solid mass is identified on ultrasound, percutaneous biopsy with ultrasound guidance can be performed.

Secondary signs of malignancy, such as architectural distortion or microcalcifications associated with an irregular mass, are highly suspicious for carcinoma. The presence of pleomorphic or linear calcifications within and/or adjacent to an indistinct or spiculated mass increase the probability that the lesion is malignant. Even without secondary signs, if an irregular mass has high-density center and fine surrounding spicules, it is regarded as suspicious for carcinoma.

Fibrocystic Change

Cancer must be considered first when an indistinct or spiculated mass is identified on mammography. However, several benign lesions can be pseudoinfiltrative on pathology and produce an appearance on mammography that is suspicious for malignancy. Most often, false positives that manifest as suspicious mammographic masses are some form of fibrocystic change, including radial scar. These lesions may be associated with microcalcifications as well, which can increase the level of suspicion for malignancy.

Hermann et al. (4) found that lesions that mimic breast cancer on mammography because they present as indistinct or spiculated masses include fibrocystic changes, fibroadenomas, or residual parenchyma in an involuting breast. Keen et al. (5) described nine lesions that presented as masses simulating carcinoma because of their margination. Indurative mastopathy (radial scar) or sclerosing papillary proliferation were the diagnoses in four patients, infarcted papilloma in one, sclerosing adenosis in three, and fat necrosis in one. In these cases, the margins of the lesion on pathologic examination were irregular and pseudoinfiltrative, and this correlates with the mammographic appearance.



Figure 5.1 HISTORY: A 46-year-old woman for baseline screening.

MAMMOGRAPHY: Left CC (A) and rolled CC medial (B) and lateral (C) views demonstrate a small indistinct mass located medially(arrows). The lesion was not observed on the MLO view, so rolled CC views were obtained to assess its location. The lesion persists on these views and moves with the superior pole of the breast. Spot-compression magnification (D) confirms the indistinct, nearly spiculated aspect of this lesion.

IMPRESSION: Highly suspicious for malignancy.

HISTOPATHOLOGY: Invasive ductal carcinoma.




Figure 5.2 HISTORY: A 64-year-old woman with a palpable thickening in the left breast laterally.

MAMMOGRAPHY: Left CC (A) and spot-magnification CC (B) and ML (C) views show a high-density spiculated mass in the outer aspect of the breast. On the magnification views (B, C), the fine spicules surrounding the lesion are evident, and the pleomorphic microcalcification with it and adjacent to it are also seen. The combination of findings is highly predictive of malignancy.

IMPRESSION: Spiculated mass, highly suggestive of carcinoma.

HISTOPATHOLOGY: Invasive ductal carcinoma with DCIS.

Sclerosing adenosis is a form of fibrocystic change characterized by a proliferation of lobules with surrounding fibrous sclerosis (6). When the condition is localized, it may masquerade as cancer on mammography and has been confused with carcinoma on histologic examination. In the early stages, there is a florid proliferation of epithelial cells. In later stages, stromal fibrosis occurs, in which coalescence of adjacent lobules produces areas of fibroepithelial proliferation and loss of normal lobular architecture (1). If the process is diffuse, the mammographic finding is diffuse, and small nodules with microcalcifications may be present. If the condition is localized, a mass with indistinct margins is often seen (1) (Figs. 5.3 and 5.4). In a series of 27 cases of sclerosing adenosis, Nielsen and Nielsen (7) reported an irregular density as the most frequent finding, but circumscribed and stellate masses were also seen. Although the density of the center of an area of sclerosing adenosis may not be as great as that of a malignancy, and the spicules may not radiate completely around the lesion, it is often impossible on mammography to differentiate such an area with certainty from a carcinoma. Therefore, sclerosing adenosis is a diagnosis made by biopsy and not by imaging alone.

A variety of forms of focal fibrocystic changes may appear as ill-defined lesions on mammography (Figs. 5.5,5.6,5.7,5.8,5.9,5.10). Focal fibrosis is a benign condition in which there is dense stromal fibrous tissue without cysts or epithelial changes (8). On mammography, fibrosis appears as dense tissue that is often irregularly marginated (9). Irregular microcalcifications that have a coarse pleomorphic appearance may be associated with fibrosis, and these may occasionally simulate carcinoma. Although biopsy is often necessary to confirm the nature of the lesion, the lack of fine linear tendrils around the border of the lesion suggests that malignancy is a somewhat less likely diagnosis. Harvey et al. (10) found that fibrous nodules that were diagnosed on core biopsy were most often masses with circumscribed or indistinct margins, but in about one fourth of cases, the findings were suspicious for malignancy.

An area of common epithelial hyperplasia or atypical ductal hyperplasia may occasionally present in a variety of ways, including as a small indistinct mass. Even a cyst or collection of cysts associated with surrounding fibrous stroma or inflammation may appear as a poorly defined










lesion. Because of the similarities in appearance of many types of fibrocystic change and in breast cancer, many biopsies performed for indistinct lesions are found to represent fibrocystic change on pathology.


Figure 5.3 HISTORY: A 52-year-old woman with no palpable findings.

MAMMOGRAPHY: Left CC view (A) and magnified image (B). The breast is heterogeneously dense. There is an ill-defined 2-cm mass of moderately high density in the outer aspect of the breast. A coned-down image shows the irregularity of the margins but lack of fine surrounding spiculations that would be more characteristic of malignancy. This finding suggests more likely a fibrocystic etiology.

IMPRESSION: Ill-defined mass, more likely fibrocystic; malignancy cannot be excluded.

HISTOPATHOLOGY: Sclerosing adenosis with epithelial hyperplasia.


Figure 5.4 HISTORY: A 38-year-old woman recalled from screening mammography for a nonpalpable mass.

MAMMOGRAPHY: Right CC spot view of the mass shows it to be isodense and lobular shaped. The margins are indistinct, and there are a few punctuate microcalcifications associated with the lesion.

IMPRESSION: Suspicious mass; recommend biopsy.

HISTOPATHOLOGY: Sclerosing adenosis.


Figure 5.5 HISTORY: A 51-year-old asymptomatic woman for a screening mammogram.

MAMMOGRAPHY: Left MLO (A) and CC (B) views. The breast is fatty replaced. In the upper outer quadrant, there is an ill-defined mass of moderate to high density with a denser center and coarse spiculation (arrow). This has a similar appearance on the MLO (A) and CC (B) views, suggesting that it is not superimposition of normal glandular structures.

IMPRESSION: Moderately suspicious, indistinct mass; carcinoma versus focal fibrocystic disease.

HISTOPATHOLOGY: Fibrocystic changes, fibrosis.


Figure 5.6 HISTORY: A 59-year-old woman with a family history of breast cancer.

MAMMOGRAPHY: Left MLO (A) and ML (B) views. There is a 2-cm, irregular, high-density lesion in the upper outer quadrant. There are a few lucencies within the mass that might suggest that it is benign; however, because of the overall density and irregular margins, biopsy was performed.

IMPRESSION: Irregular lesion, left breast, of mild to moderate suspicion for malignancy.

HISTOPATHOLOGY: Microglandular adenosis.


Figure 5.7 HISTORY: A 50-year-old woman for screening mammography.

MAMMOGRAPHY: Left MLO (A) and CC (B) views show an oval high-density mass in the upper outer quadrant. On the ML (C) view, the mass appears dense and somewhat indistinct. Further evaluation with ultrasound (D) shows the mass to be oval, circumscribed, and hypoechoic. The sonographic features suggest a benign etiology, but the high density and indistinct margin on mammography warrant biopsy.

IMPRESSION: High-density mass, recommend biopsy.



Figure 5.8 HISTORY: A 55-year-old patient with a history of fibrocystic changes.

MAMMOGRAPHY: Right CC (A) and spot-magnification CC (B) views show a mass that is dense and oval located posteriorly in the right breast. The margins are indistinct on the magnification view, and the posterior location increases the possibility for malignancy.

IMPRESSION: Indistinct dense mass, suspicious for malignancy.

HISTOPATHOLOGY: Sclerosing adenosis.


Figure 5.9 HISTORY: A 68-year-old woman for screening mammography.

MAMMOGRAPHY: Right MLO (A) and CC (B) views show an irregular mass with indistinct margins in the upper outer quadrant. The mass is somewhat high density and has a slightly different shape on the two views. No abnormality was found on ultrasound.

IMPRESSION: Irregular mass suspicious for carcinoma. (Because the ultrasound was negative, the probability for malignancy is less).

HISTOPATHOLOGY: Fibrocystic change.


Figure 5.10 HISTORY: A 56-year-old woman with a family history of breast cancer for routine screening mammography.

MAMMOGRAPHY: Bilateral MLO (A) and right ML (B) views show a focal asymmetry (arrow) in the right upper-outer quadrant. The lesion has the appearance of a low-density indistinct mass. The area was new in comparison with a prior study, and therefore it was biopsied.

IMPRESSION: Indistinct mass, suspicious for carcinoma.

HISTOPATHOLOGY: Fibrocystic changes with calcifications.

Pseudoangiomatous Stromal Hyperplasia

Pseudoangiomatous stromal hyperplasia (PASH) is a benign lesion first described by Vuitch et al. in 1986 (11). PASH may mimic breast cancer, because it may present as an irregular or indistinctly marginated mass, although often the lesion is circumscribed (12). PASH is a benign mesenchymal neoplasm composed of myofibroblasts sometimes with glandular hyperplasia.

PASH typically occurs in women younger than age 50 who typically present with a palpable mass. On mammography, PASH may present as a lobular circumscribed mass or as an indistinct distorted mass. The striking histologic feature is the complex pattern of large, empty anastomosing spaces in the dense collagenous stroma. Because of this appearance, PASH is sometimes mistaken for angiosarcoma on histology (13).

Radial Scar

Radial scar is a rosettelike proliferative breast lesion (14) that has also been described as sclerosing papillary proliferation (15), benign sclerosing ductal proliferation (16), nonencapsulated sclerosing lesion (17), infiltrating epitheliosis,


and indurative mastopathy (18). The lesion has been confused with cancer by mammographers (19) and pathologists.


Figure 5.11 HISTORY: A 77-year-old woman who presents for screening mammography.

MAMMOGRAPHY: Left MLO (A) and CC (B) views show an irregular indistinct masslike density in the upper inner quadrant. The area appears to be distorting the architecture. Considerations for this appearance are carcinoma, especially invasive lobular carcinoma; fibrocystic change with sclerosing adenosis; and radial scar.

IMPRESSION: Indistinct mass with distortion; recommend biopsy.


In a study of 32 cases of radial scar, Andersen and Gram (14) found most lesions to be small (mean diameter of 7 mm) and in a stellate configuration. On histology, a fibroelastic center is surrounded by lobules and ducts radiating outward. In 93% of cases, either papillomatosis or a benign epithelial proliferation was present. Small round microcalcifications were seen in 63% of cases (14). Because of the presence of elastosis with sclerosis and ductal distortion, a pseudoinfiltrative pattern occurs, and the lesion may be confused with carcinoma histologically (18).

On mammography, a radial scar is a spiculated defined lesion that produces retraction and distortion of surrounding structure (20) (Fig. 5.11). Microcalcifications may be associated with radial scar. Mitnick et al. (21) found mammography to be unreliable in differentiating radial scar from infiltrating carcinomas. The presence of small radiolucencies with the lesion are more in favor of a radial scar than of malignancy (3), but histologic examination is necessary to confirm the diagnosis (20,21).

Posttraumatic Changes

Intraparenchymal scars after biopsy appear as poorly defined masses, often with spiculated margins (22) (Figs. 5.12,5.13,5.14). Scars and posttraumatic changes are more visible in the first 6 months after biopsy and are less prominent after several years (23). A feature of scars that may help to differentiate them from cancers on mammography is that a scar tends to have a different configuration and density on the orthogonal views of the breast. In patients who have undergone lumpectomy and radiation therapy for treatment of primary breast carcinoma, a prominent area of scarring at the surgical site may resemble recurrent carcinoma (24,25). In these patients, it is particularly


useful to have an initial mammogram after surgery, before radiation therapy is started (26), to serve as a basis for future comparisons of the irregular postoperative density that may be present at the lumpectomy site.


Figure 5.12 HISTORY: Patient with a history of lumpectomy and radiotherapy on the right for routine follow-up.

MAMMOGRAPHY: Right MLO (A) and CC (B) views show an indistinct oval mass in the center of the right breast located behind the postsurgical skin site. The area appears dense and indistinct on the spot magnification CC view (C), but on the MLO view (A), the shape is more elongated and more dispersed. These features are most suggestive of a postsurgical site. Comparison with the prior films is essential to verify stability of the finding.

IMPRESSION: Postsurgical seroma and fat necrosis.

NOTE: The area had decreased in size in comparison with the prior postoperative study.

An acute response to trauma, such as a hematoma, may also appear as an indistinct mass (Fig. 5.15) or as a diffuse increase in density. Another radiographic feature of a hematoma that may simulate a cancer is the overlying skin thickening from the edema and bruising. Hematomas tend to resolve over a period of 3 to 4 weeks (27) but may occasionally persist for a longer time, particularly if they are of a large size. Clinical correlation is important in suggesting the correct diagnosis. Ultrasound also is helpful in demonstrating a fluid collection.

Fat necrosis is a nonsuppurative inflammatory response to trauma. Particularly if the area is associated with a desmoplastic reaction, fat necrosis may be confused with carcinoma on clinical examination. One manifestation of fat necrosis mammographically is an irregular mass that simulates carcinoma (1) (Figs. 5.16,5.17,5.18,5.19,5.20,5.21,5.22,5.23). Thickening and retraction of overlying skin may occur. On histologic examination of an area of fat necrosis, fibrous connective tissue proliferates at the periphery of the necrotic debris. The extent of fibrous response correlates with mammographic image. A marked response may appear on mammography as a spiculated mass resembling carcinoma, whereas a mild response occurs when a thin-walled radiolucent oil cyst is seen (26). Correlation with clinical history is the key in suggesting the presence of fat necrosis. The history of












a recent biopsy or severe blunt trauma in the area of abnormality should alert one to the possibility of fat necrosis. If there is any doubt about the location of a spiculated mass relative to a surgical scar, metallic markers or a wire should be placed over the scar and the film repeated to verify its position.


Figure 5.13 HISTORY: A 64-year-old woman with a status post–lumpectomy and radiotherapy on the right.

MAMMOGRAPHY: Right MLO (A) and CC (B) views show an irregular masslike density at the lumpectomy site, demarcated by the surgical clips. The area appears more dense and spiculated on the CC than the MLO, suggesting that it is more likely a scar. On the spot MLO magnification view of the tumor bed (C), the area appears less dense.

IMPRESSION: Postsurgical scar.

NOTE: The area had diminished in size from prior studies, confirming that it is a scar.


Figure 5.14 HISTORY: A 51-year-old woman status post–benign right breast biopsy.

MAMMOGRAPHY: Right MLO (A) and CC (B) views show an essentially fatty-replaced breast. The postsurgical site is indicated by a wire marker. This appears dense and spiculated on the CC view (B), but is more amorphous and vertically oriented on the MLO (A) view. The differing appearance on the two projections is typical of a scar.

IMPRESSION: Postsurgical scar.


Figure 5.15 HISTORY: A 75-year-old woman with a history of blunt trauma to the right breast.

MAMMOGRAPHY: Right ML view shows fatty replacement. There is a small indistinct mass located inferiorly (arrow). This lesion is oval with indistinct margins, and it is heterogeneous in density. This was located in the area of bruising on the skin.

IMPRESSION: Small indistinct mass, consistent with hematoma.

NOTE: Short-term follow-up mammogram showed resolution of the lesion.


Figure 5.16 HISTORY: A 57-year-old woman for screening mammography.

MAMMOGRAPHY: Right MLO (A) and CC (B) views show a fatty-replaced breast. There is a small, dense, indistinct mass located medially. The spot view (C) demonstrates the indistinct aspect of the lesion, which had developed from the mammogram a year earlier.

IMPRESSION: Suspicious mass; recommend biopsy, BI-RADS® 4.



Figure 5.17 HISTORY: A 58-year-old patient who presents for screening mammography.

MAMMOGRAPHY: Right MLO (A) and CC (B) views show a small dense mass located posterolaterally in the left breast. On spot magnification (C), the indistinct margin of this somewhat high-density mass is noted. Excisional biopsy was performed.



Figure 5.18 HISTORY: A 35-year-old woman for screening mammography.

MAMMOGRAPHY: Right ML (A) and CC (B) views show an indistinct mass in the 9 o'clock position. On the ML view, this appears dense, but on the CC view, it is less dense and more heterogeneous in appearance. On the magnified CC view (C), the area is noted to contain a fatty center, suggestive of fat necrosis. Because the patient reported no history of trauma, needle localization and excision were performed.

IMPRESSION: Indistinct mass, possible fat necrosis; recommend biopsy.

HISTOPATHOLOGY: Fat necrosis with microcalcifications.


Figure 5.19 HISTORY: A 52-year-old gravida 7, para 7 woman after right breast cancer and left breast biopsy for a benign lesion.

MAMMOGRAPHY: Left MLO (A) and enlarged CC (B) views. There is an indistinct 2-cm area of increased density (arrow) in the upper outer quadrant of the left breast. This density had increased in size since a prior examination and, because of the interval change, was regarded with a moderate degree of suspicion for malignancy. Benign secretory calcifications are adjacent to the lesion. An enlarged intramammary node (arrowhead) is present in the upper outer quadrant.

IMPRESSION: New focal area of increased density, of moderate suspicion for malignancy.

HISTOPATHOLOGY: Fat necrosis, chronic inflammation.

NOTE: Areas of fat necrosis are usually most prominent immediately after biopsy and gradually decrease in size and density over time. Occasionally, such an area may increase in size, and biopsy is usually warranted to exclude a neoplastic process.


A breast abscess is often suspected on clinical examination because of the very tender, red, hot indurated area. Abscesses tend to occur in lactating breasts, but occasionally may occur in nonlactating women. If a lesion having the clinical appearance of an abscess is found in a nonlactating patient, it should be regarded with suspicion. Most abscesses occur in the subareolar area (20), and skin and areolar thickening may be present (Figs. 5.24,5.25,5.26). Because of the extreme tenderness and the level of clinical suspicion in patients with breast abscesses, mammography may not be performed in the acute stages. The clinical appearance of a breast abscess










may be difficult to differentiate from an inflammatory carcinoma, and needle biopsy is usually performed in the acute stages. Mammography is necessary after therapy to evaluate the remainder of the breast. In an older patient, in particular, abscesses are not common and may be associated with a nearby malignancy or a papilloma obstructing a duct (Fig. 5.27).


Figure 5.20 HISTORY: A 70-year-old gravida 6, para 6 woman for routine screening.

MAMMOGRAPHY: Right ML (A) and CC (B) views and left MLO (C) and CC (D) views. The breasts show fatty replacement. In the 6 o'clock position of the right breast (A and B), there is a high-density mass appearing circumscribed on some margins and indistinct in other areas. Coarse microcalcifications are present in the periphery of this lesion. On the left (C and D) in the 6 o'clock position, there is a poorly defined mass, having a differing shape and density on the two views. Similar coarse calcifications are associated with this lesion. On both sides, but particularly on the left, some of the calcifications are round or ringlike, suggesting fat necrosis as the etiology of these densities. Because there was no definite history of trauma, biopsy was performed.

IMPRESSION: Bilateral masses, favoring fat necrosis.

HISTOPATHOLOGY: Bilateral fat necrosis.


Figure 5.21 HISTORY: A 46-year-old woman who is status post–left lumpectomy and radiotherapy. Prior films are available for comparison.

MAMMOGRAPHY: Left MLO (A) and left MLO from 1 year earlier (B) show an indistinct mass in the superior region. On the prior study, the mass was larger and more circumscribed, consistent with postsurgical seroma that is evolving into a scar.

IMPRESSION: Postsurgical scar.


Figure 5.22 HISTORY: Postmenopausal patient with a history of right breast benign biopsy.

MAMMOGRAPHY: Right MLO (A) and CC (B) views show the breast to contain scattered fibroglandular densities. There is a mass present in the upper inner quadrant that has a differing appearance on the two views. On the CC view, the lesion is high density and spiculated, but on the MLO view, an oval fatty center is noted, typical of fat necrosis.

IMPRESSION: Postsurgical scar with fat necrosis.


Figure 5.23 HISTORY: A 59-year-old woman who is status post–bilateral implant removal 1 year earlier.

MAMMOGRAPHY: Bilateral MLO views (A) show a focal asymmetry (arrow) in the right breast superiorly. This area is less dense on the CC view (B, arrow). On the ML view (C), it persists, and on spot compression (D), it appears dense and indistinctly marginated.

IMPRESSION: Indistinct mass; recommend biopsy.

HISTOPATHOLOGY: Fat necrosis and foreign-body giant-cell reaction.

NOTE: This is most likely related to the prior implants; however, its location is a somewhat unusual for the implant site.


Figure 5.24 HISTORY: A 26-year-old woman with a palpable mass in the left subareolar area.

MAMMOGRAPHY: Left MLO (A) and CC (B) views show an indistinct density in the left subareolar area. On the spot magnification CC view (C), the high-density lesion has indistinct margins posteriorly. Ultrasound (D) demonstrates that the mass is complex, and the differential diagnosis includes abscess versus tumor.

IMPRESSION: Palpable mass, possible abscess; recommend biopsy/drainage.



Figure 5.25 HISTORY: A 44-year-old woman with a painful mass in the right breast.

MAMMOGRAPHY: Coned-down right MLO (A) and CC (B) views show a high-density irregular mass in the subareolar area. There are linear extensions from the mass posteriorly, suggesting distended ducts. The skin of the areolar area is thickened. The findings of the mass and associated skin thickening are most consistent with an abscess or tumor. The patient was treated with antibiotics and drainage, and the area resolved.

IMPRESSION: Subareolar abscess.

A chronic abscess, although associated at times with some thickening and induration of the skin, does not present with the redness and tenderness found in the acute stages. A chronic abscess is usually imaged as a poorly marginated lesion in the subareolar region that may be associated with skin thickening. Sonography reveals an irregular, complex fluid-filled mass with debris. Abscesses may occur elsewhere in the breast and may be related to direct extension of infection from the skin or from surgery or trauma. In addition, infection in a lymph node may lead to suppuration and abscess formation (Fig. 5.28).

Granular Cell Tumor

Granular cell tumor was first described by Abrikossoff in 1926 (28). Granular cell tumor, also called myoblastoma, is a rare benign tumor that occurs in the tongue most frequently, but also is found in the bronchus, bile duct, or subcutaneous tissues (29). Only about 5% to 6% of granular cell tumors occur in the breast (30). The patient often presents with a firm palpable lump that may be suspicious for malignancy on clinical examination. Granular cell tumors are thought to develop from Schwann cells (13), and they are located in the subcutaneous area of the breast. These lesions are benign but locally infiltrative, and they are treated with excision.

Adeniran et al. (31), in a review of 17 cases of granular cell tumor, found that in three patients, the lesions were multifocal, occurring in the breast and elsewhere. In this






series, the mammographic findings include round circumscribed masses, indistinct densities, or spiculated masses (31). Other authors (29,30) have described a spiculated or indistinct lesion having a malignant appearance on mammography (Figs. 5.29 and 5.30).


Figure 5.26 HISTORY: A 35-year-old gravida 4, para 3, abortus 1 woman with a family history of breast cancer who presented with an indurated tender mass in the right subareolar area.

MAMMOGRAPHY: Bilateral MLO views (A), right CC view (B), and ultrasound (C). The breasts are heterogeneously dense, consistent with the age and parity of the patient. Marked asymmetry is present, with an indistinct mass (arrows) in the right subareolar area (Aand B). Nipple retraction and areolar thickening are associated with the mass. Sonography (C) shows the mass to be slightly irregular and to contain some internal echoes, suggesting thick fluid. Particularly because of the ultrasound, the favored diagnosis is an abscess; aspiration revealed purulent material.

IMPRESSION: Mass in the right breast, favoring abscess.

HISTOPATHOLOGY: Acute mastitis, breast abscess.


Figure 5.27 HISTORY: Baseline mammogram on a postmenopausal patient who presents with a tender palpable right breast mass.

MAMMOGRAPHY: Right MLO (A) and CC (B) views show an irregular, very-high-density mass with indistinct margins. The lesion occupies the central, medial aspect of the breast, and the margins are very indistinct. Excision was performed.

IMPRESSION: Highly suspicious for carcinoma.

HISTOPATHOLOGY: Abscess, small focus of DCIS.


Figure 5.28 HISTORY: A 36-year-old woman with a tender mass in the left axilla.

MAMMOGRAPHY: Left axillary view shows a high-density lesion with spiculated margins in the axilla. There are also several enlarged, dense nodes behind the mass. Differential diagnosis for the lesion includes tumor versus abscess versus hematoma.

IMPRESSION: Spiculated mass in the left axilla, suspicious for carcinoma.

HISTOPATHOLOGY: Lymph node with acute inflammation and abscess formation.


Figure 5.29 HISTORY: A 39-year-old woman with a palpable mass laterally in the left breast.

MAMMOGRAPHY: Left MLO (A) and coned-down CC (B) views. There is a slightly irregular, high-density mass in the left-mid outer quadrant located in the subcutaneous area (B, arrow). Lesions that most frequently occupy the subcutaneous region are sebaceous cysts and metastatic deposits. Another unusual lesion that may occur here is the granular cell tumor, a benign tumor of the tongue and subcutaneous tissues.

HISTOPATHOLOGY: Granular cell tumor. (Case courtesy of 

Dr. Stephen Edge, Charlottesville, VA.



A rare cause of an ill-defined lesion of the breast is fibromatosis (32). Fibromatosis or desmoid tumor most often occurs in the abdominal wall or in the superficial aponeurosis of the limbs (33). Fibromatosis can also occur in the breast, where it is thought to represent an extension from the pectoralis fascia (33,34). This is a fibroblastic lesion that behaves in a locally invasive but nonmetastasizing manner and may be associated with trauma (34,35). Microscopically, fibromatosis is composed of interlocking proliferating fibroblasts with varying amounts of collagenization and areas of myxoid degeneration and extension into the surrounding fat (36).

Fibromatosis has an appearance on mammography similar to that of carcinoma (Fig. 5.27), namely, a poorly defined or irregular mass (Figs. 5.31,5.32,5.33,5.34). Because of the involvement of the pectoralis fascia, fibromatosis is located posteriorly and is fixed. This lesion may cause both retraction of the pectoralis major muscle and the nipple because of the desmoplasia. Three cases of mammary fibromatosis were described by Yiangou et al. (33), who found that the mammographic findings were suspicious for malignancy. Cederlund et al. (37) described a case in a 28-year-old woman who had a small mass with strands extending toward the pectoralis muscle.

Fibromatosis is treated with wide local excision. The lesion may recur locally in about 25% of cases (38). In a study of 28 examples of fibromatosis, Wargotz et al. (38) found that in all cases of recurrence, the lesion was inadequately excised initially, and all the surgical margins were not clear initially.


Primary invasive breast cancers are divided into three categories: invasive, or infiltrating ductal carcinoma (IDC), invasive lobular carcinoma (ILC), and the rare carcinosarcomas. The most common type by far is invasive ductal carcinoma, not otherwise specified type. A classic appearance




of primary breast carcinoma on mammography is spiculated mass. The density of the lesion is as dense as or more dense than the parenchyma. Fine linear tendrils extend around the border of the lesion (39,40). These findings are related to the growth patterns of infiltrating carcinomas. Gross examination of these tumors reveals a firm, white gritty mass with tendrils radiating into the adjacent breast tissue. Histologic examination shows nests and cords of malignant cells associated with fibrous stroma infiltrating into the normal breast tissue (1).


Figure 5.30 HISTORY: A 61-year-old patient with a history of benign surgical biopsy on the left.

MAMMOGRAPHY: Left MLO (A) and CC (B) views show a spiculated mass at the surgical site marked by the wires on the skin, consistent with postsurgical scar. There is also a small dense mass (arrow) in the 1 o'clock position posteriorly. The mass has indistinct margins, seen best on the magnification view (C).

IMPRESSION: Postsurgical scar or posterior lesion suspicious for carcinoma.

HISTOPATHOLOGY: (Posterior lesion): Granular cell tumor.


Figure 5.31 HISTORY: A 64-year-old gravida 2, para 2 woman with a history of carcinoid tumor and a left breast biopsy 1 year ago. The biopsy was performed for a nonpalpable mass that was confirmed on specimen radiography and found to represent sclerosing adenosis.

MAMMOGRAPHY: Left MLO (A) and CC (B) views. There is a large, very-high-density, round, slightly indistinct mass in the upper inner quadrant, producing marked skin retraction. (This mass was in the region of previous biopsy.) Ultrasound showed the lesion to be solid. Because of the history of biopsy for a benign lesion, the favored diagnosis is hematoma with fat necrosis; however, neoplasia is a definite consideration because of the skin changes and high density of the mass.

IMPRESSION: Large mass, favoring postoperative changes, fat necrosis.


NOTE: Fibromatosis is a benign lesion that occurs in the area of fascia and may be related to trauma. Although rare, when it does occur in the breast, it is more often an indistinct lesion. In this case, the mass was found to be completely attached to the deep fascia at the time of resection.

On physical examination, carcinomas usually are palpated as larger than they appear on mammography. The fine extensions of tumor cells into the surrounding tissue and the fibrotic, desmoplastic reaction account for






the larger palpable mass than is evident at mammography (41).


Figure 5.32 HISTORY: A 26-year-old woman with a firm, palpable, right breast mass and nipple retraction.

MAMMOGRAPHY: Right spot CC view of the mass located far posteriorly and laterally shows the lesion to be very high density and spiculated. The lesion is tethering the pectoralis major muscle and is extending anteriorly as well.

IMPRESSION: Highly suspicious for malignancy.


NOTE: Fibromatosis or extra-abdominal desmoid tumor is associated with the pectoralis fascia and is therefore often located far posteriorly. Because of its highly infiltrative nature, it may retract the nipple or skin, even though it is not located in the retroglandular area.


Figure 5.33 HISTORY: A 47-year-old woman for screening.

MAMMOGRAPHY: Left MLO (A) and CC (B) views show a small indistinct mass (arrows) in the 12 o'clock position. On close inspection (C), long, thin tendrils surround the lesion and extend far anteriorly and posteriorly.

IMPRESSION: Suspicious for carcinoma.

HISTOPATHOLOGY: Fibromatosis (desmoid tumor).


Figure 5.34 HISTORY: A 52-year-old woman who is status postlumpectomy. Radiotherapy (RT) on the right.

MAMMOGRAPHY: Right CC (A) and MLO (B) views show an oval mass with indistinct margins in the 6 o'clock position. Spot-magnification view (C) shows the very indistinct margination of the lesion. Ultrasound (D) shows the mass (arrow) to be hyperechoic with a hypoechoic band traversing the center.

IMPRESSION: Suspicious mass right breast.

HISTOPATHOLOGY: Desmoid tumor (fibromatosis).


Figure 5.35 HISTORY: A 55-year-old gravida 2, para 2 woman with a history of multiple cysts, for routine screening.

MAMMOGRAPHY: Right MLO (A) and CC (B) views. The breast is very dense for the patient's age. There are multiple circumscribed masses (arrows) that were shown to be cystic by ultrasound. Scattered microcalcifications are present. There is a focal area of architectural distortion (curved arrow) in the 12 o'clock position. This area is spiculated, although there is no high-density center to suggest a tumor. The area had developed since a prior mammogram 18 months earlier and was, therefore, regarded with a moderate degree of suspicion for malignancy. The differential includes a radial scar versus a carcinoma.

HISTOPATHOLOGY: Intraductal carcinoma, extensive papillary and cribriform patterns.

The specified forms of invasive ductal carcinoma include tubular, medullary, mucinous, metaplastic, and adenoid cystic subtypes. In invasive ductal carcinoma, the malignant cells have extended through the duct wall and basement membrane and are invading the periductal tissues. Invasive ductal carcinoma is a solid dense tumor that may be firm or hard from the scirrhous stroma (13). The tumor cell nuclei are graded into three categories: well differentiated, intermediate, and poorly differentiated. Histologic grading describes the microscopic growth pattern and the cytologic features of differentiation (13), and includes an assessment of the extent of tubule formation by the invading malignant cells, the nuclear features, and the mitotic rate (42). The formation of tubular structures by the invading malignant cells is a good prognostic factor.

Although an intraductal carcinoma—ductal carcinoma in situ (DCIS)—occasionally presents mammographically as a small indistinct mass (43) (Fig. 5.35), this finding is more typical of infiltrating breast cancers. Infiltrating


ductal carcinoma (IDC) accounts for the largest group of malignant mammary tumors and makes up 70% to 80% of breast malignancies (44). IDCs can generally be divided into two categories based on their gross appearance: spiculated and indistinct or relatively circumscribed and microlobulated. Tumors that are spiculated in configuration have been found to be more likely associated with axillary metastases than are circumscribed tumors (44,45).


Figure 5.36 HISTORY: A 72-year-old woman with a palpable mass in the right breast.

MAMMOGRAPHY: Right MLO (A) and CC (B) views show a high-density lobular mass with microlobulated and indistinct margins. A few large round calcifications are associated with the mass and are unusual for a malignant lesion. These may be benign calcifications that were in an area occupied by the tumor, or they may be dystrophic calcifications within the malignancy.

IMPRESSION: Mass suspicious for invasive carcinoma.

HISTOPATHOLOGY: Invasive ductal carcinoma.

IDCs more typically have the sunburst appearance and the fibrotic response that lends the name scirrhous to these lesions. Scirrhous carcinomas have a marked number of fibrous stroma and elastosis, accounting for some of the spiculation seen on mammography (Figs. 5.36,5.37,5.38,5.39,5.40,5.41,5.42,5.43,5.44,5.45,5.46). Newstead et al. (46) found that a spiculated mass with or without microcalcifications was the presentation of 37.8% of IDCs, and an ill-defined mass with or without microcalcifications accounted for an additional 33.6% of cases. In 85% of the cases of IDC, the density of the lesion was higher than that of the parenchyma (46).

Many cancers—especially small, mammographically detected, and clinically occult cancers—present with fewer classical features of malignancy. Instead of appearing spiculated, these lesions are partially or completely indistinctly marginated. Often the density of the cancer is greater than expected for its size and volume and greater than that of benign lesions. Because many invasive cancers are associated with DCIS, malignant microcalcifications may occur in or adjacent to the mass. The presence of pleomorphic, amorphous or linear microcalcifications associated with a poorly marginated mass increases the probability that the lesion is malignant.

Tubular (well-differentiated) carcinoma is characterized microscopically by neoplastic elements that resemble normal breast ductules (44) because the cells are forming














tubules. The prognosis of pure or nearly pure tubular carcinomas is excellent, and the likelihood of axillary metastases is low. Assessment of the axilla in patients with tubular carcinoma may not be necessary according to some authors (47), but others have described axillary metastases even in pure tubular cancers (48). Tubular carcinoma has a typical appearance of a spiculated mass or architectural distortion (49). Tubular carcinomas tend to be detected when small (<1 cm) (49) and are most often detected on screening mammography as clinically occult lesions (50). These lesions are characterized histologically by orderly elongated tubules arranged in an irregular radiating manner and infiltrating into the surrounding parenchyma (49). There is a marked desmoplastic reaction (49,51). The lesion must be distinguished microscopically from sclerosing adenosis, which it resembles (44). There has been controversy as to whether (52) or not (53) tubular carcinomas may arise from radial scars.


Figure 5.37 HISTORY: A 55-year-old woman with a palpable mass in the left breast.

MAMMOGRAPHY: Bilateral MLO (A) and CC (B) views show a high-density, indistinct lobular mass in the left breast at 6 o'clock. On the coned-down MLO view (C), the lesion is associated with adjacent dystrophic calcifications and linear extensions anteriorly (arrow), suggesting intraductal extension of tumor. A prominent lymph node (arrowhead) is present in the left axilla.

IMPRESSION: Invasive carcinoma with DCIS.

HISTOPATHOLOGY: Invasive ductal carcinoma and micropapillary DCIS with no metastatic carcinoma in the axillary nodes.


Figure 5.38 HISTORY: A 60-year-old woman for screening.

MAMMOGRAPHY: Right ML (A) and CC (B) views demonstrated a high-density round mass with indistinct margins. The high density and the margination are suspicious for carcinoma. Sonography (C) shows the mass to be solid, slightly irregular, and associated with posterior shadowing, all of which are suspicious features.

IMPRESSION: Mammographic and sonographic findings suspicious for carcinoma.

HISTOPATHOLOGY: Infiltrating ductal carcinoma and DCIS, solid type.


Figure 5.39 HISTORY: A 56-year-old woman for screening mammography.

MAMMOGRAPHY: Bilateral MLO (A) and CC (B) views show a focal asymmetry (arrow) in the right breast at 11 o'clock posteriorly.

On the enlarged image (C), the lesion is associated with spiculation and architectural distortion. An ML magnification view (D) shows the lesion to be more masslike and spiculated and to be located superiorly in the breast. Sonography (E) shows the lesion to be solid, irregular, and densely shadowing, all features of malignancy.

IMPRESSION: Highly suspicious for carcinoma.

HISTOPATHOLOGY: Invasive ductal carcinoma.


Figure 5.40 HISTORY: 59-year-old woman with a palpable mass in the right breast.

MAMMOGRAPHY: Bilateral MLO (A) and CC (B) views show heterogeneously dense breasts. There is a focal asymmetry (arrow)corresponding to the palpable mass in the right upper outer quadrant, marked by a BB. On spot compression (C), the irregular mass with spiculated margins is seen.

IMPRESSION: Highly suspicious for carcinoma.

HISTOPATHOLOGY: Invasive ductal carcinoma.


Figure 5.41 HISTORY: A 62-year-old for screening mammography.

MAMMOGRAPHY: Right CC view (A) demonstrates an oval mass (arrow) in the 3 o'clock position and some normal-appearing lymph nodes laterally. On a spot-CC magnified view (B), the mass is low density, but it has indistinct margins. On ultrasound (C), the mass is hypoechoic, taller than wide, and is associated with slight acoustic shadowing, all of which are suspicious for malignancy.

IMPRESSION: Mass, suspicious for carcinoma.

HISTOPATHOLOGY: Mucinous carcinoma.

NOTE: Mucinous carcinoma is a specialized type of invasive ductal carcinoma that is often somewhat circumscribed. Because of the mucin contents, these tumors may be of low density.


Figure 5.42 HISTORY: A 48-year-old woman with a palpable mass with right breast at 1 o'clock.

MAMMOGRAPHY: Right ML (A) views show a high-density, irregular mass superiorly. On spot compression (B), the mass is noted to have markedly spiculated margins and to be associated with some faint amorphous microcalcifications.

IMPRESSION: Highly suspicious for malignancy.

HISTOPATHOLOGY: Infiltrating ductal carcinoma, intermediate nuclear grade.

Medullary carcinoma accounts for about 5% of all breast cancers (44) and tends to be a relatively circumscribed rather than a spiculated lesion. Mucinous or colloid carcinomas represent about 1% to 2% of breast carcinomas and, like medullary carcinomas, are circumscribed (44).

Multicentric and multifocal breast cancer occur more frequently than suspected earlier, in part because of detection with magnetic resonance imaging (MRI). Multicentric carcinoma is the occurrence of two or more cancers in different quadrants, whereas multifocal carcinoma is two or more lesions in the same quadrant




(Figs. 5.47,5.48,5.49). The clinical significance of these entities is immense, especially to the woman with newly diagnosed breast cancer who is contemplating breast conservation. A wide excision or quadrantectomy is feasible in many cases of multifocal cancer. However, multicentric carcinoma is considered a contraindication to breast conservation therapy because of the extent of surgical resection required to remove the tumors. When the radiologist observes one lesion that is suspicious for malignancy, a search for other lesions in the ipsilateral or contralateral breast is necessary. In many cases, mammography detects others, but MRI and ultrasound are also very helpful to define the extent of disease (54). In a study of mastectomy specimens of patients preoperatively diagnosed with unifocal breast cancer, Holland et al. (55) found that only 37% actually had unifocal disease. Additional malignant foci were found in 20% of cases within 2 cm of the index lesion, and in 43%, the additional tumor deposit was more than 2 cm from the index cancer (55). Both invasive ductal and ILCs can be unifocal, multifocal, or multicentric, and there can be a mixture of types as well as in situ carcinoma.


Figure 5.43 HISTORY: A 60-year-old woman with a palpable mass in the right breast.

MAMMOGRAPHY: Right MLO (A) and CC (B) view show a high-density round mass in the upper outer quadrant. Of particular concern are the margins, which are indistinct and spiculated in areas and better seen on the enlarged CC image (C).

IMPRESSION: Highly suspicious for malignancy.

HISTOPATHOLOGY: Invasive carcinoma with ductal and lobular features.


Figure 5.44 HISTORY: A 70-year-old woman with a palpable mass in the right upper-outer quadrant.

MAMMOGRAPHY: Right MLO (A) and CC (B) views. The breasts are moderately dense. In the upper outer quadrant of the right breast, there is a high-density spiculated mass (arrows). This lesion has a similar shape and density on the two views and, even if it were nonpalpable, would be highly suspicious for malignancy.

IMPRESSION: Spiculated mass in the right breast, highly suspicious for carcinoma.

HISTOPATHOLOGY: Poorly differentiated infiltrating ductal carcinoma, with metastases in five of five axillary nodes.

Infiltrating lobular carcinomas, representing 8% to 10% of all breast malignancies, are characterized by a linear arrangement of tumor cells, a tendency to grow circumferentially around ducts and lobules, and an accompanying desmoplastic reaction (44). ILC is composed of a population of small monomorphic cells that diffusely invade the tissue. Instead of forming a dense mass like invasive ductal carcinoma, ILC diffusely invades the normal parenchyma. Mammographically, ILC is often an asymmetry or architectural distortion, but sometimes it produces the appearance of a spiculated or indistinct mass (56). In comparison with ductal carcinoma, ILC has an increased likelihood for multifocal or multicentric disease, as well as contralateral


malignancy (57,58,59,60). Because of the diffuse nature of ILC, it also has a higher chance of having positive margins on excision or lumpectomy (61).


Figure 5.45 HISTORY: A 40-year-old woman with a palpable mass in the left breast.

MAMMOGRAPHY: Left ML spot view (A) shows a very-high-density mass with microlobulated margins, highly suspicious for malignancy. On ultrasound (B), the mass is of mixed echogenicity and has irregular margins with nodular extensions (arrow).

IMPRESSION: Highly suspicious for carcinoma.

HISTOPATHOLOGY: Infiltrating ductal carcinoma and DCIS, with one positive node.

Occasionally, ILCs may produce a scirrhous response (41). A spiculated lesion may extend through the subcutaneous fat to the skin, tethering it and producing the dimpling or puckering noted as secondary signs of malignancy. More often, however, the mammographic appearance is that of a subtle derangement of parenchymal architecture (62) (Figs. 5.50,5.51,5.52,5.53). Mendelson et al. (62) found that microcalcifications occurred in 25% of patients with lobular carcinoma, but the pattern of calcification was nonspecific.

Other Malignancies

An unusual form of IDC is metaplastic carcinoma. These tumors may have squamous or pseudosarcomatous changes (44). Those tumors with pseudosarcomatous metaplasia may contain areas of cartilage or bone formation and are demonstrated mammographically as unusual patterns of calcification.

Primary lymphoma of the breast is an unusual lesion with the breast being an uncommon site of extranodal involvement. The most common histology of primary lymphoma in the breast was found to be diffuse histocytic lymphoma (63). Lymphoma of the breast presents as a diffuse




increase in density of the breast or as nodules that are either well circumscribed or poorly defined but are not spiculated (64) (Figs. 5.54and 5.55). In another series, Paulus (65) found that 21 of 23 patients with primary lymphoma had non-Hodgkin's disease, and 16 of these had diffuse large-cell lymphoma. In most cases, the mammographic findings were round, fairly circumscribed masses, but some patients had indistinct masses, focal asymmetries, and areas of increased density. No calcifications were associated with these tumors. Ten of 24 patients also had ipsilateral axillary adenopathy, and one patient had unilateral adenopathy.


Figure 5.46 HISTORY: Palpable masses in the right axilla and in the right breast.

MAMMOGRAPHY: Right exaggerated CC lateral view (A) shows multiple enlarged lymph nodes in the axilla. These are very dense and somewhat indistinct, all features of malignancy. In the breast at the site of the palpable mass is a high-density oval lesion. On spot compression (B), the borders are indistinct, and the overall appearance is malignant.

IMPRESSION: Carcinoma of the right breast with metastatic nodes.

HISTOPATHOLOGY: Invasive ductal carcinoma with multiple lymph nodes involved with tumor.


Figure 5.47 HISTORY: A 53-year-old woman with a palpable mass in the right breast laterally.

MAMMOGRAPHY: Right exaggerated CC lateral view (A) shows multiple high-density masses. There is a lobular mass located anteriorly, which on spot compression (B) appears high density and indistinct. In the central aspect of the breast is a high-density irregular mass with several small adjacent satellite lesions. On spot compression (C), the irregular lesion is high density and spiculated, and there are pleomorphic microcalcifications in the vicinity.

IMPRESSION: Multicentric carcinoma.

HISTOPATHOLOGY: Invasive duct carcinoma with multiple foci of DCIS and invasive carcinoma.


Figure 5.48 HISTORY: A 42-year-old woman recalled from an abnormal baseline mammogram.

MAMMOGRAPHY: Right axillary tail view (A) shows several small indistinct densities in the upper outer quadrant of the breast. Right exaggerated CC lateral magnification view (B) shows that there are five separate, small, indistinctly marginated masses in the breast, suspicious for malignancy.

IMPRESSION: Multiple indistinct masses, suspicious for multifocal carcinoma.

HISTOPATHOLOGY: Multifocal invasive ductal carcinoma.

DiPiro et al. (66) also found in a study of 18 women with 21 non-Hodgkin's lymphomas of the breast that 62% presented as palpable masses. Mammographic findings ranged from well-defined to poorly defined masses, and all were hypoechoic on ultrasound. Another feature of lymphoma








that may be observed on mammography is enlarged axillary nodes. These nodes are usually dense, bulky, and relatively circumscribed, unlike metastatic nodes from breast cancer, in which the margins are more indistinct.


Figure 5.49 HISTORY: Palpable mass in the right breast.

MAMMOGRAPHY: Right MLO (A) and CC (B) views show dense tissue anteriorly and fatty replacement elsewhere. Multiple masses are identified, all of which are somewhat dense and irregular (arrows). Spot-compression magnification views (C, D, E, F, G) of the various masses show the indistinct and spiculated margins associated with these as well as the associated pleomorphic and amorphous microcalcifications.

IMPRESSION: Multicentric carcinoma.

HISTOPATHOLOGY: Multicentric invasive ductal carcinoma.

NOTE: When one suspicious lesion is identified, the radiologist must carefully search for other abnormalities that could represent multicentric or multifocal carcinoma.


Figure 5.50 HISTORY: A 74-year-old woman for screening mammography.

MAMMOGRAPHY: Right MLO (A) and CC (B) views show a relatively fatty-replaced breast. There is a focal asymmetry (arrow) in the right upper-outer quadrant, which on spot compression (C) appears more visible. The margins are indistinct. and the lesion is isodense.

IMPRESSION: Indistinct mass; recommend biopsy.

HISTOPATHOLOGY: Invasive lobular carcinoma.


Figure 5.51 HISTORY: A 41-year-old woman who is status post reduction mammoplasty, for screening mammography.

MAMMOGRAPHY: Bilateral MLO (A) and CC (B) views show scattered fibroglandular densities and scars bilaterally (arrows). There are several intramammary lymph nodes on the right (arrowheads). On the left at 12 o'clock is a small area of architectural distortion(white arrow). The spot-compression MLO view (C) of this area shows a persistent, small irregular mass with spiculated margins.

IMPRESSION: Postreduction mammoplasty changes, spiculated mass left breast, highly suspicious for malignancy.

HISTOPATHOLOGY: Invasive lobular carcinoma.


Figure 5.52 HISTORY: An 80-year-old gravida 0 woman with a 4-cm, palpable right breast mass.

MAMMOGRAPHY: Left (A) and right (B) CC and right MLO (C) views. There are bilateral smooth linear calcifications present, consistent with secretory disease. In the right upper-inner quadrant, there is a large, high-density spiculated mass highly suspicious for carcinoma. Incidental note is made of a normal-sized intramammary node in the upper outer quadrant.

HISTOPATHOLOGY: Infiltrating lobular carcinoma, with a large component of mucinous carcinoma. No evidence of carcinoma in 14 nodes.

Other Unusual Lesions

Other unusual lesions that can occur in the breast rarely and can be manifested as a poorly defined mass include lesions such as cholesterol granuloma, tuberculosis, actinomycosis, amyloidosis, and Wegener's granulomatosis. These reactive, inflammatory, or infective lesions all can appear both clinically and mammographically as suspicious for carcinoma.

Tuberculosis involving the breast is very rare in western countries, occurring in fewer than 0.1% of breast biopsies; however, in developing countries, the incidence is 3% to 4.4% of all breast diseases treated (67). Tuberculosis has a predilection for the patient who is lactating. Bodur et al. (68) described a 40-year-old woman with polyarticular and breast involvement with tuberculosis. Mammography showed a suspicious mass that was complex on ultrasound.

Inflammatory conditions that affect the arteries, which are the vasculitides associated with collagen vascular disease, can affect the breast rarely. Wegener's granulomatosis or necrotizing vasculitis may rarely involve the breast (Fig. 5.56). Both clinically (69) and mammographically (70), this lesion is suspicious for malignancy. The tumor is usually tender and has an irregular or spiculated contour.

Amyloid deposits in the breast can occur in patients with the predisposing systemic diseases, such as rheumatoid arthritis, multiple myeloma, and Waldenstrom's macroglobulinemia (13). Clinically, the amyloidosis of the breast is a firm, palpable mass that may contain calcifications on mammography (71).

Plasma cell mastitis and duct ectasia are common, yet the presentation as a spiculated mass is infrequent. Rarely, these patients may present with a palpable subareolar mass that contains cholesterol crystals; this is termed a cholesterol granuloma (72).




Figure 5.53 HISTORY: A 66-year-old gravida 8, para 6, abortus 2 patient for screening mammography.

MAMMOGRAPHY: Left ML (A) and CC (B) views. There are two indistinct masses (arrows) in close proximity in the upper outer quadrant of the left breast. The masses are of relatively high density for their small size and in comparison with the background parenchymal density. There is a slight difference in the shape of each mass on the two views; nonetheless, these remain very focal and irregular.

IMPRESSION: Two indistinct masses, highly suspicious for multifocal carcinoma.

HISTOPATHOLOGY: Infiltrating lobular carcinoma, intraductal carcinoma, lobular carcinoma in situ, no evidence of carcinoma in 21 axillary nodes.

A variety of vascular lesions can occasionally occur in the breast. The malignant vascular tumor is angiosarcoma, which typically presents as a large, indistinctly marginated mass that may contain microcalcifications (73). A bluish discoloration of the skin has been described in 17% of patients (73), which is thought to be related to the vascular nature of the lesion. Angiosarcoma can develop after breast irradiation for treatment of breast cancer; the prognosis is poor.

Benign vascular tumors include hemangiomas, subcutaneous hemangiomas, and angiomatosis. Many hemangiomas are detected on mammography (Fig. 5.57) and are not clinically evident, but large lesions may be palpable. Often these are circumscribed masses with calcifications (74), but some lesions may be indistinct or even appear as tortuous vessels (13).








Figure 5.54 HISTORY: A 68-year-old woman with a history of lymphoma of the right eye who presents for screening.

MAMMOGRAPHY: Bilateral MLO (A) and CC (B) views show irregular indistinct masses in both breasts. On spot-compression left CC (C) and spot-compression right MLO (D), the indistinct margins of the masses are seen.

IMPRESSION: Bilateral indistinct masses, lymphoma versus carcinoma.

HISTOPATHOLOGY: Non-Hodgkin's lymphoma.

NOTE: Lymphoma in the breast most often presents as circumscribed or indistinct masses. Adenopathy also may be associated or may be the sole presentation.


Figure 5.55 HISTORY: A 75-year-old woman with history of lymphoma, for routine screening mammography.

MAMMOGRAPHY: Right MLO (A) and CC (B) views. There is an isodense indistinct mass located in the posterior upper aspect of the right breast (arrow) on the MLO view (A). On the CC view (B), the lesion is located medially (arrow). A second, smaller irregular lesion is also presented laterally (curved arrow). Although these lesions could represent lymphoma, the favored diagnosis is a primary breast carcinoma.

IMPRESSION: Two irregular lesions, probably neoplastic: primary carcinoma versus lymphoma.

HISTOPATHOLOGY (BOTH SITES): Malignant lymphoma, mixed small- and large-cell type.


Figure 5.56 HISTORY: A 50-year-old woman with history of Wegener's granulomatosis, who presents with a palpable left breast mass.

MAMMOGRAPHY: Left CC view (A) and enlarged CC view (B) show the palpable mass to be round and high density but to have very indistinct margins. The primary consideration is breast carcinoma, although occasionally other lesions can have this appearance.

HISTOPATHOLOGY: Vasculitis, consistent with Wegener's granulomatosis.


Figure 5.57 HISTORY: A 23-year-old woman with a palpable mass in the superior aspect of the right breast.

MAMMOGRAPHY: Right MLO (A) and CC (B) views show an irregular, high-density large mass in the 12 o'clock position of the breast. The mass has a tubulonodular appearance and indistinct margination, suggesting that it is either ductal or vascular in origin.

IMPRESSION: Right breast mass, suspicious for an intraductal lesion or vascular lesion.



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