Uterine Smooth Muscle Tumor of Uncertain Malignant Potential: Clinicopathologic-Sonographic Characteristics, Follow-Up and Recurrence

BACKGROUND: Uterine smooth muscle tumor of uncertain malignant potential (STUMP) is rare tumor, and regarded as sub-classification in uterine smooth muscle tumors between benign and malignant criteria. In this study, we evaluated characteristics of cases with STUMP diagnosis in a 10-year period. METHODS: We retrospectively evaluated medical records of patients with histopathological STUMP diagnosis in Istanbul Training and Research Hospital, a tertiary center. We analyzed preoperative demographic, clinical features and postoperative follow-up. Preoperative sonographic data were re-evaluated. RESULTS: The mean age was 42 years. One patient was postmenopausal, and five patients were premenopausal. All of them had a complaint of meno-metrorrhagia. We re-evaluated preoperative sonographic images of patients, and defined 83.3% as well-defined margins, 66.7% hyperechoic, 100% heterogeneous, 66.7% non-cystic, 50% calcification and 66.7% acoustic shadowing. Pathologic features showed mean number of mitosis 8, mild atypia 66.7%, and necrosis 33.3%. In a 24-year-old unmarried female patient with myomectomy, we detected recurrance of tumor in sonographic and MRI studies after 11 months, and confirmed the diagnosis via tru-cut biopsy. There was no relevance between sonographic findings and atypia, necrosis and mitosis. The recurrence was not in relationship with mitosis, degree of atypia and necrosis. We found no relevance between tumor diameter and mitosis, atypia, necrosis and recurrence. CONCLUSIONS: STUMP is classified as an intermediate form, histopathologically so calling it benign or malignant for sure is not possible. Singulary, solidity, hyperechogenicity, heterogenecity and features of acoustic shadowing and margins can guide us to preoperative sonographic diagnosis. Recurrence/metastasis after many years from operation can be seen, and those patients should be followed long term.