AMR SeriesSelected Case From the Arkadi M. Rywlin International Pathology Slide Club Polypoid Endometriosis in the Pouch of Douglas in a Perimenopausal WomanGunawardane, Dimuth N. MB, BS, PhD, FRCPA; Allen, Philip W. MB, BS, FRCPA Author Information Department of Surgical Pathology, SA Pathology at Flinders Medical Centre, Bedford Park, SA, Australia The authors have no NIH funding or conflicts of interest to disclose. Reprints: Philip W. Allen, MB, BS, FRCPA, Department of Surgical Pathology, SA Pathology at Flinders Medical Centre, Bedford Park, SA 5042, Australia (e-mail: [email protected]). All figures can be viewed online in color at http://www.anatomicpathology.com. Advances In Anatomic Pathology: September 2015 - Volume 22 - Issue 5 - p 331-334 doi: 10.1097/PAP.0000000000000081 Buy Metrics Abstract A 50-year-old female had a hysterectomy and bilateral salpingo-oophorectomy for adenomyosis, uterine leiomyomas, ovarian and cervical endometriosis. Nine months later, organ imaging revealed a 43×74×52 mm, apparently malignant extraperitoneal mass lying between the vagina and rectum. The patient had been receiving a progestogen. Preoperative needle biopsies were interpreted as recurrent endometriosis. The mass was easily excised and sections were interpreted as polypoid endometriosis with a decidual reaction and foci of necrosis. Slides circulated to the club were from the excised specimen. The majority agreed with this diagnosis although a minority favored a Mullerian adenosarcoma. One club member commented that pseudosarcomatous change, including periglandular stromal cuffing and condensation, may occur in patients on hormones, especially tamoxifen. The patient was well with no recurrence 15 months after surgery. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.