Subserosal Myoma Associated with Stump (Smooth Muscle Tumors of Uncertain Malignancy Potential): A Case Report

Smooth muscle tumors of the uterus are typically benign, but a rare subset known as smooth muscle tumors of uncertain malignant potential (STUMP) poses diagnostic challenges. First classified by the World Health Organization in 2003 due to their atypical histological features, STUMPs are difficult to distinguish from benign leiomyomas and malignant leiomyosarcomas. This case study describes a 53-year-old woman with a large abdomino-pelvic mass, initially suspected to be sarcoma. Clinical and imaging evaluations, including MRI, led to exploratory laparotomy, revealing a subserosal myoma associated with STUMP. Histopathological analysis confirmed the diagnosis, underscoring the complexities in differentiating STUMPs from other uterine tumors. STUMPs account for a portion of uterine sarcomas, and accurate diagnosis relies on specific histological criteria, including nuclear atypia, mitosis index, and tumor necrosis. Advanced imaging, such as dynamic MRI, helps improve differentiation between STUMP, leiomyosarcoma, and leiomyoma. Although STUMPs are rare, they typically have a better prognosis than leiomyosarcomas, with lower recurrence rates. However, due to their uncertain behavior, patients require long-term monitoring. The limited understanding of STUMPs highlights the need for continued research and clinical vigilance to improve diagnosis and management strategies.