Extraordinary Case ReportLongstanding Eccrine Syringofibroadenoma With Evidence of Carcinomatous TransformationPagliuca, Francesca MD*; Moscarella, Elvira MD†; Argenziano, Giuseppe PhD†; Ronchi, Andrea MD*; Franco, Renato PhD*Author Information *Pathology Unit, Department of Mental and Physical Health and Preventive Medicine, University of Campania “L. Vanvitelli,” Naples, Italy; and †Dermatology Unit, Department of Mental and Physical Health and Preventive Medicine, University of Campania “L. Vanvitelli,” Naples, Italy. Correspondence: Andrea Ronchi, Division of Pathology, Department of Mental and Physical Health and Preventive Medicine, Università degli Studi della Campania “Luigi Vanvitelli,” Via Luciano Armanni 20, Naples 80100, Italy; (e-mail: firstname.lastname@example.org). The authors declare no conflicts of interest. The American Journal of Dermatopathology: October 2020 - Volume 42 - Issue 10 - p 780-782 doi: 10.1097/DAD.0000000000001651 Buy Metrics Abstract Eccrine syringofibroadenoma (ESFA) is a cutaneous proliferation of eccrine ducts, mainly encountered in association with other dermatoses or skin tumors. Although a benign condition, either considered as a hamartoma or a reactive hyperplasia rather than a real neoplasm, some evidence suggests that longstanding ESFA can undergo malignant change. The recognition of such opportunity could have important therapeutic implications. We present a case of ESFA showing areas of carcinomatous transformation, discussing its morphological and immunohistochemical findings. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.