EP22.15: Uterine smooth muscle tumours of uncertain malignant potential: a diagnostic and therapeutic challenge

Uterine smooth muscle tumours of uncertain malignant potential (USTMP) are a diverse group with uncertain behaviour, distinct from benign leiomyoma or malignant leiomyosarcoma. While often slow-growing with prolonged survival, the risk of recurrence and spread remains significant. Retrospective study of fifteen STUMP patients among 275 myoma carriers who underwent surgery over five years from September 2018 to February 2024. Compared clinico-echographic and anatomopathological characteristics with women undergoing myomectomy or hysterectomy for presumed benign uterine masses. STUMP accounts for 5.45% of the patients studied. The clinical features associated with STUMP resemble those of typical leiomyoma. The average age of the patients was 44, the majority of whom were peri menopausal. The most frequent clinical presentation was abnormal uterine bleeding in 50%, followed by pelvic pain such as heaviness in 30% and abdominal mass in 10% of cases. STUMPs mainly appeared on pelvic Doppler ultrasonography as single tumours in 60% of cases, with a median size of 6cm. The appearance was hypoechoic in 80% of cases, with moderate to intense colour Doppler, and blurred or irregular boundaries in 3 patients. Histologically, mild to moderate cellular atypia was predominant in 50%, followed by moderate to severe mitosis in 30% and necrosis in 2 cases. Most STUMPs had a Ki-67 index ranging from 10% to 30%. Five young women wishing to maintain their fertility opted for myomectomy, while the remainder underwent total hysterectomy with ovarian conservation, which remains the treatment of choice. Regular, close follow-up was initiated for the conservative treatment group. Two recurrences of endometrial carcinosarcoma were observed. A multi-disciplinary approach is essential in the management of STUMP. Molecular biology techniques can be used to identify the genes directly involved in carcinogenesis.