Science and Education Publishing American Journal of Medical Case Reports 2374-216X 4 5 2016 5 4 Mullerian Adenosarcoma Occurring in a Young Female and Originally Diagnosed as an Endometrial Stromal Nodule 150 152 EN Modupeola O. Samalia Tara Chang M. Ruhul Quddus Department of Pathology, Women & Infants Hospital, Alpert Medical School of Brown University, Providence, RI, USA C. James Sung Katrine Hansen W. Dwayne Lawrence AJMCR2016451 10.12691/ajmcr-4-5-1 2016 2 3 2016 3 30 2016 5 2 Mullerian Adenosarcoma (MA) is most commonly encountered in postmenopausal females in the sixth decade of life. We present the case of a 21-year old female with a high BMI and a clinical presentation suggestive of polycystic ovarian disease; she presented with abnormal vaginal bleeding. A laparoscopy/hysteroscopy by her primary physician demonstrated an intracavitary and submucosal appearing mass which was clinically considered to be a polypoid submucosal leiomyoma. The patient underwent endometrial curettage. The specimen was comprised of multiple fragments of soft tan-red haemorrhagic tissues aggregating to 6.5 x 4.0 x 0.6 cm. An original diagnosis of endometrial stromal nodule was made on this material; however, on consultative review the diagnosis was changed to a mullerian adenosarcoma. No stromal overgrowth or heterologous differentiation was identified. Immunohistochemical studies demonstrated stromal cells were positive for oestrogen receptor (ER) and CD10. We emphasize the young age of this patient with a mullerian adenosarcoma as well as the pitfall of making a specific diagnosis of endometrial stromal neoplasms based on an endometrial curettage.