Hospital for Sick Children's, The: Atlas of Pediatric Ophthalmology & Strabismus, 1st Edition

11

Orbit

Alex V. Levin

Thomas W. Wilson

Dan DeAngelis

Robert Pashby

Jeffrey Hurwitz

The orbit contains multiple tissues, each of which is subject to disease. A disease process in any tissue may have contiguous effects on neighboring tissues within this closed and compact compartment, in particular the optic nerve. Compression, stretching, or ischemia of the optic nerve will lead to rapid visual field and/or vision loss, which may or may not be irreversible. Tumor of virtually any orbital tissue can cause optic nerve compression. Likewise, hemorrhage, infiltration, infection, or vascular malformation may cause optic nerve compression. In the latter, if there is a lymphangiomatous component, compression may only occur when infection, for example, an upper respiratory viral systemic infection, results in temporary swelling of the orbital lesion. Tumors of the optic nerve itself are covered in Chapter 9: Optic Nerve.

Proptosis occurs when there is an increase in retrobulbar orbital volume. This can be acute or chronic. It may result from a variety of benign and malignant lesions. Benign tumors include vascular malformations and cysts. Orbital malignancy may be local (e.g., rhabdomyosarcoma, optic nerve glioma) or systemic (e.g., leukemia, neuroblastoma). Infectious causes of proptosis may also be acute (e.g., bacterial orbital cellulitis) or chronic (e.g., parasitic cyst). Acute inflammatory disease includes pseudotumor. As the globe translates forward for any reason, the optic nerve is stretched, resulting in serious vision loss. Surgical decompression of the orbit may be needed.

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Figure 11.1 Orbital Dermoid

Orbital dermoids are common lesions noted of the anterior orbit in children. They arise in the locations of the frontozygomatic suture and, less commonly, the frontonasal sutures. During embryogenesis, dermal elements may get “pinched off” and reside in the suture lines. Superficial dermoids are easily palpable and generally grow with facial growth. Deeper dermoids may not be noted until later in childhood and may have intracranial extension through the suture with a mass on either side of the cranial vault, sometimes called “dumbbell dermoids.” The cysts' walls have dermal elements and the contents can contain keratin hair follicles. Rupture by trauma, including surgery, can elicit a severe granulomatous response.

 

Figure 11.2 Lymphangioma

Lymphangiomas are benign lesions that have been more recently categorized as part of a spectrum of combined venous–lymphatic abnormalities. Recurrent proptosis and visual loss can occur through recurrent hemorrhages. The left image shows a child at baseline with an inferior orbital mass. With upper respiratory tract infection, dramatic swelling can occur (right image). Proptosis and visual loss may occur. Surgical extirpation or transcutaneous draining of affected areas may be needed.

 

Figure 11.3 Capillary Hemangioma

Capillary hemangiomas commonly occur on the lids and anterior orbit. Clinically, they range from small isolated lesions to larger tumors that can cause ptosis (as seen in this child's left medial upper lid) and visual loss. There may or may not be an overlying “strawberry” lesion (Chapter 2: Lids and Adnexa, Figs. 2.17 and 2.18). Systemic considerations include the Kasabach-Merritt syndrome, a consumption coagulopathy associated with large hemangiomas. The natural history involves a proliferative phase in the first year of life followed by regression. Indications for treatment include amblyopia, proptosis, and optic neuropathy. Intralesional steroids are not recommended for deep lesions like the one shown here. Other treatment options include surgical excision, systemic steroids, or interferon.

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Figure 11.4 Rhabdomyosarcoma

Rhabdomyosarcoma is the most common malignant orbital tumor of childhood and the third most common soft tissue tumor of childhood. It typically presents with an acute onset of proptosis, globe dystopia, visual loss, and an orbital mass. The tumor may extend beyond the confines of the orbit into the sinuses and intracranial cavity. Diagnosis is made by incisional biopsy. Although previous treatment modalities included exenteration, the current preferred treatment is with combination orbital radiation and systemic chemotherapy. Rhabdomyosarcoma should be considered in the differential diagnosis of almost all rapid and slow-growing orbital masses.

 

Figure 11.5 Teratoma

Teratomas are rare orbital tumors that characteristically have components of all three germ layers: Ectoderm, endoderm, and mesoderm. They present with massive congenital proptosis, facial distortion, and reduced visual acuity. Histologically, these tumors can contain cartilage, bone, hair follicles, and neural tissue. Treatment may range from excision of the localized tumor to orbital exenteration. Visual prognosis is poor due to the massive compression and stretching of the optic nerve.

 

Figure 11.6 Ewing Sarcoma

Ewing sarcoma is an uncommon, primarily bony tumor of the extremities that can involve the orbit through metastases. It presents as a lytic lesion of the bony orbit or a soft tissue mass, as shown here. Treatment consists of combined aggressive surgical resection and chemotherapy. Note the proptosis demonstrated in both the clinical and radiologic images. The lesion is usually slow growing. The primary bone lesion may or may not be identified at the time of orbital presentation.

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Figure 11.7 Preseptal Cellulitis

Infection of the tissues anterior to the orbital septum is called preseptal or periorbital cellulitis. The infection is usually bacterial. If there is a primary break in the skin that served as an access for bacteria, the organism is usually Staphylococcus or Streptococcus. In a well child, oral antibiotics may be effective. In a child who has not been vaccinated for Haemophilus influenzae, this organism must be ruled out. Neonates, unwell children, immunocompromised children, and those with sickle cell anemia should probably be treated with parenteral antibiotics to avoid sepsis.

 

Figure 11.8 Orbital Cellulitis

This child has orbital cellulitis with infection extending posterior to the orbital septum. Characteristic signs include proptosis, restricted eye movements, and signs of optic nerve compromise. These children tend to be unwell. Orbital cellulitis is commonly secondary to infectious sinusitis, which breaks through the medial orbital wall, introducing pathogens into the orbit. If a localized subperiosteal abscess forms, symptoms may be limited to proptosis and some motility restriction. Treatment consists of intravenous antibiotics and usually surgical drainage with sinus drainage where indicated.

 

Figure 11.9 Cavernous Sinus Thrombosis

Cavernous sinus thrombosis is a rare complication of orbital cellulitis. When the intraorbital infection courses posteriorly to the orbital apex, it can enter the cavernous sinus unilaterally or even spread to the contralateral side. These patients are systemically very ill with unilateral or bilateral ophthalmoplegia of varying degrees, proptosis, and reduced vision. Treatment is with intravenous anticoagulation and antibiotics.

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Figure 11.10 Idiopathic Orbital Inflammation (Inflammatory Pseudotumor)

The cause of orbital pseudotumor is unknown. Patients present with a subacute onset of pain with eye movements, proptosis, diplopia, headache, and systemic signs. This patient is attempting left gaze with a restriction of right adduction and an erythematous right medial rectus insertion. Peripheral blood eosinophilia is not uncommon in these cases. Imaging reveals a diffusely enlarged extraocular muscle that involves the tendinous insertion, unlike thyroid eye disease, which spares the tendon (Chapter 16: Endocrine, Fig. 16.5). More diffuse orbital involvement may also be seen. Biopsy may be helpful and the response to treatment with systemic corticosteroids particularly useful, as most of these patients will gain significant improvement over 24 to 48 hours.

 

Figure 11.11 Microphthalmia with Cyst

Microphthalmia is a congenital ocular malformation that results in a globe that is smaller than normal. It may be associated with a cystic component due to failure of fusion of the choroidal fissure and outpouching of the neurosensory retinal tissues. A normal-sized globe is a required stimulus for growth of the normal orbit and adnexal structures. Patients with microphthalmia may need surgery to increase orbital volume using orbital expanders, whereas patients with cysts may get volume expansion by the presence of the cyst alone.

 

Figure 11.12 Anophthalmia

Anophthalmia is a very rare condition characterized by the absence of any visible or rudimentary ocular tissue. If these patients have any rudimentary ocular tissue in their orbits that can be visualized on ultrasonography or neuroimaging, then the diagnosis is microphthalmia. True anophthalmia is due to a failed or incomplete formation of the optic stalk and vesicle. Some reports link anophthalmia to pesticide use and/or mutations in a number of developmental genes. Orbital reconstruction with volume expansion may be necessary in some cases. (Photograph provided by Ayesha Khan, Pakistan, fellow, 2004–05.)