By Gary M. White, MD
Waxy, purpuric papulonodules and plaques about the eyes. Courtesy Robert Goltz, MD
Amyloidosis is the deposition of proteinaceous fibrils in the extracellular matrix. Amyloid typically shows apple-green birefringence when specimens stained with Congo red are viewed under polarized light. Various clinical presentations may arise.
Primary systemic amyloidosis (PSA) is a clonal B-cell disorder and may be associated with multiple myeloma, lymphoma, or can even be idiopathic. In PSA, there is deposition of monoclonal immunoglobulin light chains.
Periorbital waxy papules and nodules, along with petechia and purpura after the slightest trauma (pinch purpura) are characteristic. Post-proctoscopic periorbital purpura is a classic but uncommon presentation. Other cutaneous features include macroglossia, "empty fingertips," alopecia, bulla, cord-like thickening of superficial blood vessels, sclerodermatous infiltration of the face, hands and feet, soft-tissue enlargement of the shoulders (shoulder-pad sign), cerebriform nodules on the scalp, infiltrated nodules in the oral mucosa, and nail dystrophy. Systemic features include weight loss, carpal tunnel syndrome, hepatomegaly and paresthesias. Approximately one-third of cases are associated with myeloma. Death may occur from cardiac or renal failure.
Rarely, patients with primary systemic amyloidosis may develop diffuse sclerosis of the skin resembling scleroderma (a.k.a. scleroderma amyloidosum) [BJD 1999;140;1169].
Workup should include general HP (with emphasis on lymphadenopathy, hepatosplenomegaly, cardiac failure and nerve dysfunction), SPEP, Bence Jones proteins, Beta 2 microglobulin (make it a beta sub 2), echocardiogram, EKG, and bone marrow biopsy. There is an absence of circulating protein in approximately 30% of the cases, although more sensitive methods may detect one in up to 89% of the cases.
Referral to a specialist is in order. No single reliable therapy has yet been found. Cytotoxic chemotherapy (e.g., colchicine, melphalan, prednisone) is often used and is aimed at controlling the aberrant plasma cell population and thus reducing the amount of precursor light chains. Initial treatment with the proteasome inhibitor bortezomib along with dexamethasone followed by autologous stem cell transplantation is being tried.
Survival is enhanced by supportive treatment of organ failure. Cardiac and renal transplantation and dialysis may be necessary. Patients with amyloidosis and myeloma have a median survival of 5 months de spite treatment.
Amyloid may invade the lip. Cutis 2014 August;94(2):E10-E12
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