Uterine Smooth Muscle Tumor of Undetermined Malignant Potential (STUMP): A Diagnostic Challenge

Smooth muscle tumors of the uterus can range from benign leiomyoma (LM) to malignant leiomyosarcoma (LMS) histologically. Between these two entities lies a gray zone of smooth muscle tumors of undetermined malignant potential, commonly known as STUMP. Their diagnosis has always been a challenge for the pathologists. Once diagnosed, clinicians face difficulties in managing STUMP because of the lack of discrete treatment guidelines. Here, we report a case of a 52-year-old lady who presented in an emergency with severe menorrhagia. On examination, the patient was pale and there was a 4x3 cm size polyp protruding through the internal ostium. Hysteroscopy with endometrial biopsy and polypectomy were done. The polypectomy specimen was diagnosed as STUMP after a thorough histopathological examination and immunohistochemistry (IHC). The specimen was re-examined in two other reputed institutes, as there was a dilemma between the diagnosis of STUMP/leiomyosarcoma. The patient was treated with a radical hysterectomy, considering the upstaged diagnosis of leiomyosarcoma. The final histopathological diagnosis of the hysterectomy specimen was STUMP. The patient did not receive any adjuvant therapy. Presently, she is on follow-up every six months and has not developed any recurrence till now. The aim of reporting this case is to enrich the existing literature on this rare diagnosis and highlight the fact that STUMP can also present as a uterine polyp. This is probably the first case of STUMP presenting as a uterine polyp.