title: Squamomelanocytic tumor: a case report and further insights into its possible histogenesis.
abstract: We report a case of combined squamomelanocytic tumor of the skin. Clinically, the lesion was felt to be a squamous cell carcinoma. Histologically, it was characterized by large epithelioid cells admixed with basaloid cells with central squamous differentiation. Immunohistochemical staining showed both cell populations to be reactive with Melan A, BEREP4, and Pan Keratins. Ultrastructural studies revealed simultaneous features of squamous differentiation (dense cytoplasmic tonofilaments with well-developed desmosomes) and melanocytic differentiation (mature/pigmented melanosomes) in the same cell population. This is the second reported case in the English literature with documented biphenotypic or divergent differentiation at the ultrastructural level. The behavior of squamomelanocytic tumor is uncertain given the rarity of reported cases.
authors.affiliation: *Department of Pathology and Laboratory Medicine, Saint Luke's-Roosevelt Hospital Center, Columbia College of Physicians and Surgeons, New York, NY; †Miraca Life Sciences, Miraca Research Institute, Newton, MA; ‡Tufts University School of Medicine, Boston, MA; §Department of Dermatology, Tufts University School of Medicine, Boston, MA; and ¶Department of Pathology and Laboratory Medicine, Beth Israel Medical Center, Albert Einstein College of Medicine, New York, NY.
authors.forename: George
authors.initials: G
authors.lastname: Jour
authors.forename: Alberto
authors.initials: A
authors.lastname: Paniz-Mondolfi
authors.forename: Jason
authors.initials: J
authors.lastname: Reidy
authors.forename: Brienne D
authors.initials: BD
authors.lastname: Cressey
authors.forename: Seth
authors.initials: S
authors.lastname: Rosenthal
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D002294:Carcinoma, Squamous Cell / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008545:Melanoma / Q000473:pathology; D018193:Neoplasms, Complex and Mixed / Q000473:pathology*; D012878:Skin Neoplasms / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor