title: Focus of tricholemmal differentiation (tricholemmal carcinoma) within Bowen's disease/carcinoma.
abstract: Bowen's disease (BD)/carcinoma is a type of squamous cell carcinoma of the skin, however, the possibility of adnexal differentiation (the development of sebaceous carcinoma or porocarcinoma) occurring in BD/carcinoma has been suggested. We herein describe a case of BD with superficial invasive carcinoma, which showed a clear cell focus, demonstrating tricholemmal differentiation. This clear cell focus showed the following findings: primarily composed of clear cells, somewhat columnar clear cells aligned in a palisade along a discernible basement membrane, tricholemmal keratinization and glycogen contained within the cells. In addition, the immunohistochemical profile in this clear cell focus, namely, negative staining for cytokeratin (CK)1 and positive staining for CK17 and calretinin in the inner cells of the neoplastic lobule, corresponded to that of the outer root sheath cells. This case suggested that adnexal differentiation can rarely occur within true BD/carcinoma, although adnexal carcinomas are commonly associated with a simple bowenoid change.
authors.affiliation: Division of Dermatology, Nakao Clinic, Saga University, Saga, Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Misago
authors.affiliation: Department of Pathology, Faculty of Medicine, Saga University, Saga, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Toda
authors.affiliation: Division of Dermatology, Nakao Clinic, Saga University, Saga, Japan.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Nakao
mesh_terms: D000369:Aged, 80 and over; D014408:Biomarkers, Tumor; D001913:Bowen's Disease / Q000473:pathology* / Q000601:surgery; D064032:Calbindin 2 / Q000378:metabolism; D018280:Carcinoma, Skin Appendage / Q000473:pathology* / Q000601:surgery; D005260:Female; D018859:Hair Follicle / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D053556:Keratin-1 / Q000378:metabolism; D053537:Keratin-17 / Q000378:metabolism; D012878:Skin Neoplasms / Q000473:pathology* / Q000601:surgery
chemical_list: D014408:Biomarkers, Tumor; C576764:CALB2 protein, human; D064032:Calbindin 2; C491616:KRT1 protein, human; D053556:Keratin-1; D053537:Keratin-17
keywords: Bowen's disease; adnexal differentiation; calretinin; clear cell; tricholemmal carcinoma