INTRODUCTION Amyloidosis represents a variety of disorders that result in abnormal glycoprotein deposition. It can be associated with certain infections, inflammatory processes, and plasma cell dyscrasias. Primary amyloidosis occurs in the setting of no known predisposing disease. Secondary amyloidosis is typically superimposed on a chronic inflammatory disease such as leprosy, osteomyelitis, or rheumatoid arthritis. Amyloidosis occurring with multiple myeloma is considered a distinct entity. Skin deposits occur in up to 30% of patients with amyloidosis, predominantly on the lids, face, neck and extremities, and may be localized or generalized. The most common variety of amyloidosis to affect the eyelid skin is primary localized, representing 75% or more of all ophthalmic cases. In this variety the amyloid deposits consist of light chains secreted by bone marrow plasma cells. In contrast, generalized amyloidosis involving the eyelids may be associated with cardiac, renal, hepatic, or splenic involvement. The respiratory tract, bladder, adrenal glands and urethra may also be involved. Weakening of blood vessels by amyloid deposition can cause episodes of internal and intestinal bleeding. Involvement of the tongue causing macroglossia has been reported in about a third of systemic cases.
CLINICAL PRESENTATION Ocular adnexal amyloidosis is characterized by amyloid deposition within the deep connective tissue layers of the eyelids, conjunctiva, and anterior orbit. It may not be associated with systemic amyloidosis. The eyelid deposits appear as small, yellowish or pink, waxy papules. Damage to associated vessels may lead to ecchymotic foci underlying the amyloid material, resulting in a very characteristic purple or magenta-colored lesion. Deposition within the upper eyelid tarsal plate and other tissues may present as ptosis with significant superior visual field loss. Yellowish papules or plaques can also occur on the conjunctiva and are associated with ocular discomfort. When the cornea is involved blurred vision is associated with a vascularized corneal mass. Presentation can be atypical including diffuse eyelid swelling, or recurrent eyelid bleeding without any other signs. Affected patients often present with weight loss and weakness.
HISTOPATHOLOGY Amyloid is an extracellular, amorphous, eosinophilic deposit that appears glassy and homogeneous ("hyaline") in H&E stained sections. Amyloidosis of the eyelid may be predominantly in the conjunctiva or skin, with deposits forming nodules replacing the connective tissue and surrounding blood vessels (shown on right below). The deposits contain few cells, usually fibroblasts or chronic inflammatory cells. Congo red causes the amyloid deposits to be orange to red under normal illumination; with polarized light the deposits have green to yellow birefringence (dichroism); an example of amyloid birefringence is illustrated in the terminology chapter under "birefringence." Collagen may stain weakly with Congo red, but it does not exhibit birefringence or dichroism when observed with polarization microscopy.
DIFFERENTIAL DIAGNOSIS The differential diagnosis includes Darier's disease, lipoid proteinosis, xanthelasma, and acanthosis nigricans. Diagnosis can be established by punch, shave, or excisional biopsy and histopathologic evaluation.
TREATMENT Treatment of the underlying condition is paramount. Although no proven effective treatment has yet been established to control localized involvement of the ocular adnexa, meticulous surgical debulking of the deposits has been reported to be effective. However, recurrences are common.
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