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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?

Which histologic feature or “deposit” is common to all porphyrias?

The porphyrias are a group of diseases resulting from defects in the enzymes that regulate heme biosynthesis. The biochemical and clinical features are different for each type of porphyria, yet all demonstrate similar cutaneous histology with deposits of eosinophilic, hyaline material around blood vessels. This material stains positively with the periodic acid–Schiff stain and represents reduplicated basal lamina or type IV collagen.