Eponyms in the Dermatology Literature Linked to Stains Used in Skin Biopsies

Staining is an auxiliary technique used in microscopy to enhance contrast in the microscopic image. Stains and dyes are frequently used in biology and medicine to highlight structures in biological tissues for viewing, often with the aid of different microscopes [1]. Hematoxylin and eosin stain (H&E stain or HE stain), is the routine staining for skin biopsies. However, in some circumstances, dermatopathologists use other stains. For example, the Fontana-Masson Stain is used for melanin as it can be difficult to decide whether a brown pigment is lipofuscin, hemosiderin, or melanin. At pH4, melanin granules reduce silver nitrate to metallic silver, a histochemical reaction that reveals accumulations of black material wherever melanin is located. The Fontana-Masson Stain can be used, also, to detect melanin of dematiaceous fungi [2]. Each stain may give a particular colour to a specific structure in the tissue. For example, Alizarin red binds directly to calcium ions, resulting in an orange-red color [3]. In Foote’s or Snook’s stain, the reticulin fibers will be black. Leder stain (Naphthol ASD chloroacetate esterase), will stain Mast cell cytoplasm red (not dependent on presence of granules). Also stains myloid cells (example, leukemia cutis). Lipid will be stained by Oil red O (requires fresh frozen tissue, as lipid is removed during processing). In addition to Sudan black and Osmium tetroxide (both require fresh tissue). Iron will be stained by Prussian blue, also known as Perls stain, after its inventor, German pathologist Max Perls (1843-1881). In this stain ferric ions react to form a deep blue. It is useful to distinguish melanin from hemosiderin (example:hemosiderin in pigmented purpuric dermatosis). It does not demonstrate iron in intact red blood cells. There are also several other stains which are not used commonly in dermatopathology. For example: Movat’s stain which is a pentachrome stain originally developed by Henry Zoltan Movat in 1955 and later modified by H. K. Russell, Jr. in 1972. It is used to highlight the various constituents of connective tissue. In this stain, the nuclei , elastic fibres will be black; collagen fibres, reticular fibres will be yellow; ground substance, mucin will be blue; Fibrin will be bright red Muscle will be red. Also, Weigert’s elastic stain which will show elastic fibers, blue coloured while cell nuclei gets red or blue. It is named for, Karl Weigert, or Carl Weigert (1845-1904), (Fig. 1), who was a German pathologist. There are several eponyms linked to the stains used in dermatopathology practice. In Table I [4-19], we listed some examples. EPONYMS IN THE DERMATOLOGY LITERATURE LINKED TO STAINS USED IN SKIN BIOPSIES