title: Pilomatricomal horn: a new superficial variant of pilomatricoma.
abstract: We describe a pilomatricomal horn on the right arm of a 39-year-old man. Although initially the tumor was clinically thought to be a verruca vulgaris, the microscopic features were similar to those found in classic pilomatricoma, except for the epidermal location and the presence of a cutaneous horn. Light microscopy showed replacement of the epidermis by basaloid cells, with masses of cornified material containing shadow cells that formed a cutaneous horn. Whereas classic pilomatricoma is confined to the deep reticular dermis or subcutis, the present case represents a unique heretofore unreported epidermal variant of pilomatricoma that pathologists should be aware of to differentiate it from malignant epidermal tumors.
authors.affiliation: Department of Pathology, Hospital Universitario "12 de Octubre", Madrid, Spain.
authors.forename: Juán P García
authors.initials: JP
authors.lastname: de la Torre
authors.forename: Ana
authors.initials: A
authors.lastname: Saiz
authors.forename: Mónica
authors.initials: M
authors.lastname: García-Arpa
authors.forename: José L
authors.initials: JL
authors.lastname: Rodríguez-Peralto
mesh_terms: D000328:Adult; D001132:Arm / Q000473:pathology / Q000601:surgery; D005500:Follow-Up Studies; D006201:Hair Diseases / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008297:Male; D018296:Pilomatrixoma / Q000473:pathology* / Q000601:surgery; D012878:Skin Neoplasms / Q000473:pathology* / Q000601:surgery; D013997:Time Factors; D016896:Treatment Outcome