Coexistence of Smooth Muscle Tumor of Uncertain Malignant Potential (STUMP), Symplastic Leiomyoma, and Squamous Cell Carcinoma in Situ in a Nulliparous Patient: A Case Report

Background: Smooth muscle tumors of uncertain malignant potential (STUMPs) constitute a rare and diagnostically challenging subset of uterine mesenchymal neoplasms. Their clinical behavior is unpredictable, and preoperative distinction from benign leiomyomas or leiomy­sarcomas remains difficult. Coexistence with cervical squamous neoplasia is exceedingly uncommon and sparsely documented. Case Presentation: We report the case of a 36-year-old nulliparous woman with a 12-year history of symptomatic uterine leiomyomatosis who presented with severe abnormal uterine bleeding and life-threatening anemia. Imaging over the years demonstrated progressively enlarging uterine masses, including a large pedunculated lesion occupying the entire pelvis. Emergency total hysterectomy was performed due to hemodynamic instability. Gross examination revealed three distinct tumors: a large transcervical polypoid mass, a bilobulated subserosal tumor and an intramural leiomyoma. Histopathological evaluation demonstrated a colliding tumor composed of a transcervical symplastic leiomyoma associated with cervical squamous intraepithelial neoplasia with foci of early stromal invasion, and a subserosal STUMP characterized by focal necrosis and cytologic atypia but low mitotic activity. The postoperative course was favorable, and the patient was referred to gynecologic oncology for long-term surveillance. Discussion: This case is notable for the unusual coexistence of a STUMP, a symplastic leiomyoma, and cervical squamous neoplasia with microinvasion in a patient significantly younger than the typical age reported for STUMPs. The case highlights the diagnostic difficulty, unpredictable biological behavior, and lack of standardized management or follow-up guidelines for STUMP, emphasizing the importance of individualized treatment and monitoring due to recurrence risk. Conclusion: Uterine STUMPs remain a management challenge given their uncertain malignant potential, radiologic ambiguity, and absence of clear follow-up recommendations. This case Article Details How to Cite