Malignant Progression of Uterine Smooth Muscle Tumor of Uncertain Malignant Potential (STUMP) to Metastatic Leiomyosarcoma: A Six-Year Case Evolution

Uterine smooth muscle tumors of uncertain malignant potential (STUMP) are rare tumors with histologic features of both benign leiomyoma and leiomyosarcoma.Due to this, their clinical behavior is unpredictable, and long-term outcomes of progressing into malignant leiomyosarcoma should be closely investigated.We present the case of a 42-year-old woman diagnosed with STUMP following laparoscopic-assisted myomectomy.Despite total abdominal hysterectomy and negative initial follow-up, she developed metastatic leiomyosarcoma involving the thoracic spine and posterior chest wall within three years and expired due to multiorgan failure six years later.This case underscores the potential malignant behavior of STUMP and raises the question of the need for adjuvant therapy, such as chemotherapy, in selected high-risk patients' posthysterectomy.