211Chapte

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The basics: diagnostic terms, skin anatomy, and stains

MelaninFontanaMasson A silver stain that results in a black

precipitate with melanin

CalciumVon Kossa A silver stain that stains calcium salts black Examples: pseudoxanthoma elasticum,

calcinosis cutis, calciphylaxis

Alizarin red Binds directly to calcium ions, resulting in an

orange-red color

LipidsOil red O Requires fresh frozen tissue, as lipid is

removed during processing

Sudan black Requires fresh tissue

Osmium tetroxide Requires fresh tissue

BacteriaBrownHopps A modification of the BrownBrenn

technique Grampositive organisms stain blue and

Gramnegative organisms stain red

Figure 1-73 Blue iron deposition from Monsels tattoo with Perls iron stain

Figure 1-74 Absence of melanin in vitiligo is contrasted with adjacent normal skin (Fontana-Masson)

Figure 1-75 Calcium deposition in the small vessels of the subcutaneous fat in calciphylaxis (Von Kossa)