Prolapsed Uterine Smooth Muscle Tumor of Uncertain Malignant Potential: A Case Report and Review of Radiologic Findings

Introduction: Uterine smooth muscle tumor of uncertain malignant potential (STUMP) is a rare tumor that arises in the myometrium of the uterus. It is regarded as an intermediate malignant tumor according to the recent World Health Organization classification. Few studies have reported the radiologic findings of STUMP, and the differentiation of STUMP from leiomyoma remains controversial. Case description: A 42-year-old nulliparous female presented at our institution with massive vaginal bleeding. Radiological studies, including ultrasonography, computed tomography (CT), and magnetic resonance imaging, revealed an oval-shaped mass with well-defined margins in the uterus protruding into the vagina. The patient underwent a total abdominal hysterectomy, and the final pathology was confirmed as STUMP. Conclusion: Distinguishing STUMP from leiomyomas based solely on radiological findings can be challenging. However, if the uterine mass appears as a single mass lacking acoustic shadowing on ultrasound and demonstrates diffusion restriction with high T2 signal intensity on magnetic resonance imaging, consideration of STUMP may be necessary for proper patient management, given the poor prognosis associated with this tumor.