Selected case from the Arkadi M. Rywlin international pathology slide club: Polypoid endometriosis in the pouch of douglas in a perimenopausal woman

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 43×74×52mm, 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.