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Deposition Disorders

»How is “deposition disorder” defined?
»What is amyloid?
»How is amyloid identified?
»Name the various types of amyloidosis.
»What are the cutaneous manifestations of primary or myeloma-associated systemic amyloidosis? How often do they occur?
»Name the other organ systems that may be involved in primary or myeloma-associated amyloidosis.
»Compare lichen amyloidosis and macular amyloidosis.
»How does nodular amyloidosis present? With what is it associated?
»In what setting is secondary systemic amyloidosis seen?
»What are the systemic manifestations of secondary systemic amyloidosis?
»What is lipoid proteinosis?
»What is colloid milium?
»Which histologic feature or “deposit” is common to all porphyrias?
»Which porphyria classically demonstrates the largest deposits? What are its cutaneous features?
»Name some of the cutaneous mucinoses.
»Describe the clinical lesions seen in pretibial myxedema and its disease associations.
»Describe the clinical lesions seen in lichen myxedematosus.
»What serum abnormality has been associated with scleromyxedema?
»Describe the clinical lesions in scleredema and its disease associations.
»What is a digital mucous (myxoid) cyst?
»What substance is elevated in gout?
»Where is the uric acid deposited in gout? What are the resulting clinical manifestations?
»How is gout treated?
»How many types of calcinosis cutis are there?
»What underlying medical conditions have been associated with metastatic calcinosis cutis?
»What is calciphylaxis and who develops it?
»What is osteoma cutis?

 
 
 

What are the cutaneous manifestations of primary or myeloma-associated systemic amyloidosis? How often do they occur?


Primary systemic amyloidosis. Characteristic periorbital purpuric plaques.
Fig. 16.2 Primary systemic amyloidosis. Characteristic periorbital purpuric plaques.
Cutaneous lesions are seen in about 30% of cases of primary or myeloma-related systemic amyloidosis. The most common skin lesions are petechiae or ecchymoses due to amyloid deposition within blood vessel walls with subsequent fragility and dermal hemorrhage. These are often seen at sites predisposed to trauma, such as the hands or intertriginous areas. Pinching the skin gives characteristic purpuric lesions known as “pinch purpura.” Purpura around the eyes may occur spontaneously but is also seen following proctoscopy or vomiting (“postproctoscopic purpura”) (Fig. 16-2). Waxy papules, nodules, or plaques may be present. Less common manifestations include sclerodermoid plaques, bullae, alopecia, and nail dystrophy.