title: A case of non-selective phagocytosis of hemosiderin and melanin of dermal histiocytes in stasis dermatitis.
abstract: A case study was undertaken to determine whether or not the same dermal histiocytes could phagocytose both melanin and hemosiderin simultaneously. A biopsy specimen was taken from a pigmented lesion of the lower leg of a 57-year-old woman with stasis dermatitis. The specimen was processed for histology, conventional transmission electron microscopy and electron-probe X-ray microanalysis. Histologically, numerous histiocytes with their cytoplasm packed with either Prussian blue-positive granules or Fontana-Masson-positive granules were distributed almost equally in the dermis. Electron microscopically, the dermis had many histiocytes with their cytoplasm containing solitary or compound electron-dense substances. The electron-dense substances were classified into three types according to their degree of electron density. By electron-probe X-ray microanalysis, these electron-dense substances were classified into iron-containing and non-iron-containing substances. Both substances were seen in the cytoplasm of the same histiocytes and even in the same compound electron-dense substance. The former were siderosomes and the latter were probably melanosomes. These results show that the same dermal histiocytes probably phagocytose non-selectively both hemosiderin and melanin granules.
authors.affiliation: Department of Dermatology, Faculty of Medicine, Tottori University, 36-1 Nishimachi, 683-8504 Yonago, Japan.
authors.forename: Maria Rosario P
authors.initials: MR
authors.lastname: Rivera
authors.forename: Masahiko
authors.initials: M
authors.lastname: Ishihara
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Mihara
mesh_terms: D004577:Electron Probe Microanalysis; D005260:Female; D006485:Hemosiderin / Q000378:metabolism*; D006644:Histiocytes / Q000378:metabolism*; D006801:Humans; D007868:Leg Dermatoses / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D008543:Melanins / Q000378:metabolism*; D008854:Microscopy, Electron; D008875:Middle Aged; D010587:Phagocytosis; D012867:Skin / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*
chemical_list: D008543:Melanins; D006485:Hemosiderin