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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 is amyloid?

Amyloid is a protein with distinct tinctorial and ultrastructural properties found as extracellular deposits. It is composed of a nonfibrillary protein known as the amyloid P component and a fibrillary component that is derived from various sources. The amyloid fibril has an antiparallel, b-pleated sheet configuration. Ultrastructurally, amyloid is composed of rigid, nonbranching fibrils measuring 6 to 10 nm in diameter.