Case ReportsAbout a Case of Diffuse Endometrial Squamous Metaplasia After Resectoscopic Myomectomy: A Potential Diagnostic Pitfall for Gynecologists and PathologistsAmico, Paolo MD*; Caltabiano, Rosario MD*; Zizza, Gaetano MD†; Lanzafame, Salvatore MD*Author Information *Department G.F. Ingrassia, Section of Anatomic Pathology †Department O.GI.RA, Policlinico, University of Catania, Catania, Italy Reprints: Salvatore Lanzafame, MD, Department G.F. Ingrassia, Section of Anatomic Pathology, University of Catania, Santa Sofia 87 Street, 95123 Catania, Italy (e-mail: email@example.com). Received for publication November 26, 2009; accepted January 29, 2010 Paolo Amico and Rosario Caltabiano have contributed equally. Applied Immunohistochemistry & Molecular Morphology: July 2010 - Volume 18 - Issue 4 - p 392-395 doi: 10.1097/PAI.0b013e3181d6bd31 Buy Metrics Abstract We report a case of diffuse endometrial squamous metaplasia found after in a resectoscopic myomectomy specimen. A 35-year-old woman underwent an office hysteroscopy that showed a submucosal leiomyoma. After pharmacologic treatment with a GnRH gonadotropin-releasing hormone agonists (GnRHa) leuprolide acetate, the patient underwent a resectoscopic myomectomy. Histologic examination showed fragments of myometrial tissue with the foci of endometrial glands with diffuse features of squamous metaplasia; in part classical, mature type; and in part immature type, and the so-called “morula type.” Presence of endometrial squamous metaplasia in the endometrium may produce dramatic histologic changes on biopsies and sometimes it may be difficult to distinguish it from primitive primary carcinomas of nonendometrioid histology, representing therefore, a potential diagnostic pitfall. GnRHa therapy could play a possible role in the onset of squamous metaplasia. So the pathologist and gynecologist must take into account this possible metaplastic change for a correct clinicopathologic assessment and to avoid overtreatment. © 2010 Lippincott Williams & Wilkins, Inc.