title: Extramammary Paget disease: Immunohistochemistry is critical to distinguish potential mimickers.
abstract: Extra-mammary Paget disease (EMPD) is a rare intra-epithelial carcinoma that is usually found on the apocrine-rich skin of the perineum. We report 2 cases in which EMPD was initially misdiagnosed on the initial punch biopsy as melanoma-in-situ and Bowen disease respectively. Reasons for the misdiagnoses included a rare pigmented axillary variant of EMPD in the first case and atypical bowenoid features on H&E in the second. The cases are described with a critical review of the histopathological findings, along with a review of the current literature. This highlights the necessity of a comprehensive immunohistochemical panel for the assessment of intra-epithelial pagetoid atypical cells.
authors.affiliation: National Skin Centre, Singapore.
authors.forename: Etienne Ce
authors.initials: EC
authors.lastname: Wang
authors.forename: Yung Chien
authors.initials: YC
authors.lastname: Kwah
authors.forename: Wee Ping
authors.initials: WP
authors.lastname: Tan
authors.forename: Joyce Ss
authors.initials: JS
authors.lastname: Lee
authors.forename: Suat Hoon
authors.initials: SH
authors.lastname: Tan
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis / Q000473:pathology; D000368:Aged; D001706:Biopsy; D001913:Bowen's Disease / Q000175:diagnosis; D002272:Carcinoembryonic Antigen / Q000032:analysis; D003951:Diagnostic Errors; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D053552:Keratin-7 / Q000032:analysis; D058965:MART-1 Antigen / Q000032:analysis; D008297:Male; D015580:Mohs Surgery; D009077:Mucins / Q000032:analysis; D060787:Neoplasm Grading; D010145:Paget Disease, Extramammary / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D017430:Prostate-Specific Antigen / Q000032:analysis; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000473:pathology; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D016896:Treatment Outcome
chemical_list: D002272:Carcinoembryonic Antigen; C507497:KRT7 protein, human; D053552:Keratin-7; D058965:MART-1 Antigen; C548667:MLANA protein, human; D009077:Mucins; D017430:Prostate-Specific Antigen