title: Adenoid cystic carcinoma-like pattern in spiradenoma and spiradenocylindroma: a rare feature in sporadic neoplasms and those associated with Brooke-Spiegler syndrome.
abstract: Spiradenoma is a benign, morphologically well-defined cutaneous adnexal neoplasm that is closely related to cylindroma. We present the rare occurrence of adenoid cystic carcinoma (ACC)-like areas in 7 spiradenomas and 1 spiradenocylindroma, not described in the English literature to date. The ACC-like areas were a minor but significant component in all lesions and were usually multifocal and blended with the conventionally appearing parts of the neoplasms. The ACC-like areas were typified by cribriform formations of epithelial cells concentrically arranged around gland-like spaces filled with mucin, homogeneous eosinophilic material, or granular basophilic material. In some neoplasms, only mucin occurred in these pseudoglandular structures, whereas in other cases, a combination of all 3 secretory products was encountered. Although well-developed bilayered glands with a demonstrable peripheral myoepithelial cell layer were not recognizable in the ACC-like areas, immunohistochemistry demonstrated myoepithelial differentiation in these portions of the tumors. When present in the ACC-like areas, ductal structures manifested a rather squamoid lining, without a recognizable peripheral myoepithelial cell layer. It is concluded that the ACC-like pattern, although a rare feature and of no clinical consequence, is a distinctive finding in a minority of cases and extends the morphological spectrum of spiradenoma and spiradenocylindroma occurring sporadically or in the setting of Brooke-Spiegler syndrome. It represents a potential diagnostic pitfall, particularly in a limited biopsy specimen where the changes may be misdiagnosed as ACC.
authors.affiliation: Sikl's Department of Pathology, Charles University, Medical Faculty Hospital, Pilsen, Czech Republic
authors.forename: Fredrik
authors.initials: F
authors.lastname: Petersson
authors.forename: Heinz
authors.initials: H
authors.lastname: Kutzner
authors.forename: Dominic V
authors.initials: DV
authors.lastname: Spagnolo
authors.forename: Michele
authors.initials: M
authors.lastname: Bisceglia
authors.forename: Denisa
authors.initials: D
authors.lastname: Kacerovska
authors.forename: Marina
authors.initials: M
authors.lastname: Vazmitel
authors.forename: Michal
authors.initials: M
authors.lastname: Michal
authors.forename: Dmitry V
authors.initials: DV
authors.lastname: Kazakov
mesh_terms: D006607:Adenoma, Sweat Gland / Q000473:pathology*; D000368:Aged; D003528:Carcinoma, Adenoid Cystic / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013544:Sweat Gland Neoplasms / Q000473:pathology*; D013577:Syndrome