title: Carcinoma ex spiradenoma/cylindroma confirmed by immunohistochemical and molecular loss-of-heterozygosity profiling.
abstract: We present a case of spiradenoma/cylindroma with admixed carcinoma of unknown origin, resolved using immunohistochemical and molecular loss-of-heterozygosity (LOH) profiling. The patient, a woman in her mid-70s, initially presented with separate mammary (ductal) carcinomas of the right and left breasts that were treated with radical mastectomies. For 9 years, the patient remained disease free until complaining of a slow-growing skin nodule on the lower back that was excised under clinical suspicion of metastatic mammary carcinoma. Histopathological exam revealed a benign eccrine spiradenoma/cylindroma and an intermixed carcinoma, with a differential diagnosis of either primary eccrine carcinoma or mammary carcinoma metastatic to the spiradenoma/cylindroma. Histological features and immunohistochemical staining favored eccrine carcinoma but not unequivocally; therefore, LOH profiles were performed on archival paraffin block tissue from the 3 neoplastic lesions (4 components). The mammary carcinomas showed disparate LOH at 5 of 7 (right breast) and 4 of 7 (left breast) informative genetic loci, establishing these carcinomas as separate primary neoplasms. Both the spiradenoma/cylindroma and eccrine carcinoma revealed no LOH at the tested loci, establishing the unknown carcinoma as an independent carcinoma arising within a spiradenoma/cylindroma. This neoplasm is referred to in the literature as carcinoma ex spiradenoma/cylindroma and spiradenocylindrocarcinoma.
authors.affiliation: Department of Dermatology and Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. jukicdm@upmc.edu
authors.forename: Drazen M
authors.initials: DM
authors.lastname: Jukic
authors.forename: Laura M
authors.initials: LM
authors.lastname: Drogowski
authors.forename: James R
authors.initials: JR
authors.lastname: Davie
mesh_terms: D006607:Adenoma, Sweat Gland / Q000235:genetics / Q000473:pathology*; D000368:Aged; D001943:Breast Neoplasms / Q000473:pathology / Q000601:surgery; D003528:Carcinoma, Adenoid Cystic / Q000235:genetics / Q000473:pathology*; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D019656:Loss of Heterozygosity; D009378:Neoplasms, Multiple Primary / Q000235:genetics / Q000473:pathology*; D016609:Neoplasms, Second Primary / Q000473:pathology; D016133:Polymerase Chain Reaction; D013544:Sweat Gland Neoplasms / Q000235:genetics / Q000473:pathology*