Ocular Pathology/Oncology AAO Self-Assessment Flashcards
What is the most common histopathologic cell type in orbital rhabdomyosarcoma? Pleomorphic Embryonal Undifferentiated Alveolar
Embryonal rhabdomyosarcoma is the most frequent cell type in orbital tumors (80%); alveolar and undifferentiated sarcomas are less common. In embryonal rhabdomyosarcoma, the tumor cells resemble developing skeletal myocytes, with variation from small round cells to larger elongated cells with cross striations. There is a better survival rate of patients with embryonal rhabdomyosarcoma than with other forms of this tumor.
An eye with a retained, iron foreign body becomes blind and is subsequently enucleated. In which ocular tissue would Prussian blue stain demonstrate the iron impregnation? Lens nucleus Zonules Ciliary epithelium Sclera
Iron is concentrated primarily in the epithelial cells of the eye (epithelium of the cornea, iris, ciliary body, lens, and retinal pigment epithelium). It is also seen in the iris muscles, trabeculum, and neural retina. Bivalent iron (ferrous) is more toxic than the ferric form. The intraocular iron accumulating in these tissues is toxic, leading to hyperpigmentation of the iris from iron deposition (heterochromia), iron cataract (siderosis lentis), trabecular meshwork scarring with glaucoma, and retinal degeneration with characteristic ERG changes. Early removal of an iron foreign body is important to avoid permanent retinal damage. Iron does not accumulate in the lens nucleus, sclera or zonules.
Which of the following neoplasias is an epithelial malignancy of the conjunctiva? Mucoepidermoid carcinoma Actinic keratosis Malignant lymphoma Squamous papilloma
Mucoepidermoid carcinoma of the conjunctiva is a rare malignant tumor of the conjunctival epithelium. It resembles squamous cell carcinoma, but is more agressive and invasive. It demonstrates intracytoplasmic mucin vacuoles with PAS stains, with squamous and mucin-producing malignant cells. Squamous papilloma is a benign epithelial tumor. Actinic keratosis is a premalignant dysplastic change in the epithelium, usually in the skin. Lymphomas are not epithelial tumors.
Cotton-wool spots are clinical signs of abnormalities of what tissue? nerve fibers Müller cells astrocytes glial cells
Ischemia of the inner retina leads to damage to the ganglion cells and their axons, which are located in the nerve fiber layer of the retina. These nerve fibers, in response to the injury, develop localized accumulations of axoplasmic material known as cytoid bodies(figure). Clinically the areas of swollen axons constitute the “cotton-wool spots” seen in a variety of retinal ischemic conditions. The degenerated axon is eventually phagocytized by microglial cells, leaving areas of inner retinal atrophy and small glial scars.
Which of the following orbital tumors characteristically demonstrates fluctuations in size? Optic nerve glioma Hemangioendothelioma Lymphangioma Hemangiopericytoma
Orbital lymphangiomas are rare, benign tumors of the orbital producing orbital masses, usually in childhood and adolescence. They produce orbital pain, mass effects on extraocular muscles or the optic nerve, hemorrhage, and proptosis. They may be superficial or deep, within the orbit involving the intra- or extraconal spaces. Swelling or hemorrhage may be associated with fluctuations in the size of the tumor and the resultant proptosis. Rapidly progressive proptosis in a young child requires the exclusion of rhabdomyosarcoma.
In acute angle closure glaucoma, what characteristic damage may be seen in the optic nerve pathologically after prolonged high intraocular pressure? Disc neovascularization Optic nerve demyelination Deep optic nerve cupping Cavernous optic nerve atrophy
Schnabel initially described cavernous optic nerve atrophy in 1892. Extremely high intraocular pressure can lead to infarction of the optic nerve, as the vascular supply to the post-laminar nerve from the short posterior ciliary arteries is compromised, leaving cavernous spaces. Initially the infarction is manifest by ischemic swelling of the nerve, but this is followed by glial phagocytosis of the necrotic nerve fiber bundles, leaving large cavernous spaces separated by the pial septae. The cavernous spaces contain hyaluronic acid (Zimmerman, 1967), which is presumed to move from the vitreous into the anterior optic nerve. This unique form of optic nerve atrophy also is seen with vascular disease involving the proximal optic nerve, including atherosclerosis and vasculitis. A recent autopsy study showed cavernous optic nerve degeneration to be found in older female patients, possible associated with low-grade vascular insufficiency. Optic nerve demyelination and optic disc neovascularization are not characteristic of glaucoma. Disc cupping is not specific for acute angle closure glaucoma.
Band keratopathy is deposition of what material in Bowman's layer? keratin mucopolysaccharide calcium amyloid
Band keratopathy is the deposition of calcium hydroxyapatite in Bowman’s layer, which is readily demonstrated pathologically by the von Kossa stain on tissue sections (figures). The calcification of Bowman’s layer occurs in the interpalpebral area,and develops initially in the corneal periphery with a clear zone adjacent to the limbus. The opacity may condense and form a horizontal band obscuring vision. Small holes in the opaque membrane may represent areas where the corneal nerves pass to the surface. The causes of band keratopathy are multiple: ocular inflammatory disease, which is usually chronic and may lead to phthisis bulbi; hypercalcemia; hereditary forms of band keratopathy; hyperphospatemia; chronic exposure to mercury; and intraocular silicone. Evaluation may warrant metabolic and renal studies. Treatment is possible with topical chelation using ethylenediaminetetraacetic acid (EDTA). Rare cases of transient band keratopathy have been reported where correction of the underlying biochemical abnormalities has led to complete resolution.
What is the most common type of orbital lymphoma? Follicular lymphoma Marginal zone lymphoma Lymphoblastic lymphoma Mantle cell lymphoma
Ocular adnexal lymphomas compose 8% of extranodal lymphomas. The most common subtype (80%) of these are marginal zone lymphomas of muscosa-associated lymphoid tissue (MALT) type.
A 70-year-old woman complains of 6 months of irritated, dry eyes. Early symblepharon are present in both lower fornices, with areas of conjunctival injection. The tear film is diminished and the corneas are dry. There is no history of toxic injury or previous surgery. If you suspect benign mucous membrane pemphigoid, what test should you ask the pathologist to perform on the conjunctival biopsy you submit? Congo red for amyloid Alcian blue for mucopolysaccharides Sections for immunoglobulins H&E stain for eosinophils
The diagnosis of benign mucous membrane pemphigoid can be established pathologically by the demonstration of immunoglobulins and complement in the epithelial basement membrane zone. Some of these immunohistochemical stains work best with frozen tissue sections, which can be generated from fresh tissue that has been stored in an appropriate transport media (Michels) or transported with dry ice. Paraffin fixed sections can be used for newer immunohistochemistry stains for complement. The pathologic diagnosis is important to justify the necessary prolonged use of immunosuppressive drugs in an older patient. H&E and Alcian Blue are not helpful. Negative staining with congo red is not diagnostic.
Which of the following patterns is the most common histologic subtype of malignant melanoma of the eyelid? Nodular Superficial spreading Acral-lentiginous Lentigo maligna
Melanoma of the eyelid is a relatively rare tumor making up less than 1% of eyelid cancers. It typically appears as a pigmented thickening (tumor) of the eyelid or extension of pigment from the conjunctiva. Malignant melanoma of the skin is classified differently than conjunctival and uveal melanomas. They can arise de novo from a pre-existing nevus or from an acquired area of melanosis representing horizontal intraepithelial spread of melanoma prior to invasion. Superficial spreading melanoma demonstrates individual and clusters of malignant melanocytes involving the epithelial layers of affected skin prior to invasion. In the eyelid, lentigo maligna melanoma was the most common histologic type, accounting for 61% of all melanomas and 53% of invasive melanomas. Superficial spreading melanoma accounted for 22% and nodular melanoma for 17% of all melanomas.
