title: An osteoid variant of cutaneous melanoma in a dog detected by S100 and melan a markers.
abstract: Osteoid malignant melanoma is a rare type of melanoma described in humans and dogs with some areas of bone differentiation. In this tumour, the origin of the bone matrix remains unclear. We report one case of this variant with, for the first time, a cutaneous origin in a dog. Malignant melanomas are aggressive tumours. Amelanotic tumours are sometimes difficult to recognize as they require immunohistochemical evaluation for an adequate diagnosis and we have used anti-vimentin, S100, and melan A antibodies for identification. Melan A is less sensitive but more specific than S100 in identifying amelanotic melanomas. This tumour was positive for vimentin, S100 and melan A, including the areas of osteoid. These results suggest osteoid differentiation of tumour cells rather than induced stromal metaplasia.
authors.affiliation: Laboratoire d'Histocytopathologie Vétérinaire, 95 rue raspail, 94700 Maisons-Alfort, France. pierre.maliver@neuf.fr
authors.forename: P
authors.initials: P
authors.lastname: Maliver
authors.forename: M
authors.initials: M
authors.lastname: Estrada
authors.forename: M
authors.initials: M
authors.lastname: Lagadic
authors.forename: M
authors.initials: M
authors.lastname: Mialot
authors.forename: S
authors.initials: S
authors.lastname: Manin
authors.forename: J-J
authors.initials: JJ
authors.lastname: Fontaine
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor / Q000096:biosynthesis*; D001859:Bone Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D004283:Dog Diseases / Q000175:diagnosis* / Q000473:pathology; D004285:Dogs; D007150:Immunohistochemistry / Q000662:veterinary; D058965:MART-1 Antigen; D008297:Male; D008545:Melanoma / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000276:immunology; D009418:S100 Proteins / Q000096:biosynthesis / Q000276:immunology; D014746:Vimentin / Q000096:biosynthesis / Q000276:immunology
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D058965:MART-1 Antigen; C548667:MLANA protein, human; D009363:Neoplasm Proteins; D009418:S100 Proteins; D014746:Vimentin