title: Ultrastructural morphology of hypomelanosis in equine cutaneous papilloma.
abstract: The morphology of hypomelanosis occurring in experimentally induced equine papillomas was investigated. Histologically, dopa-positive functioning melanocytes were decreased in number from the basal layer in the epidermis. Electron-microscopically, melanogenic organelles in the melanocytes were degenerate and melanosomes were decreased in number and size. In addition, the melanocytes had some abnormal melanosomes including melanosome complexes and giant melanosomes. Some abnormal melanosomes were also present in the keratinocytes. The hypomelanosis seemed to be related to a disturbance in melanin synthesis and melanocytic-keratinocytic interaction in the epidermal melanin unit.
authors.affiliation: Department of Comparative Pathology, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Hamada
authors.forename: C
authors.initials: C
authors.lastname: Itakura
mesh_terms: D000818:Animals; D004295:Dihydroxyphenylalanine / Q000378:metabolism; D006734:Horse Diseases / Q000378:metabolism* / Q000473:pathology; D006736:Horses; D008543:Melanins / Q000378:metabolism*; D008544:Melanocytes / Q000378:metabolism / Q000648:ultrastructure; D008854:Microscopy, Electron; D010212:Papilloma / Q000378:metabolism / Q000648:ultrastructure / Q000662:veterinary*; D012867:Skin / Q000378:metabolism*; D012878:Skin Neoplasms / Q000378:metabolism / Q000648:ultrastructure / Q000662:veterinary*
chemical_list: D008543:Melanins; D004295:Dihydroxyphenylalanine