Uterine Smooth Muscle Tumors of Uncertain Malignant Potential ( STUMP ): Clinical Course and Follow‐Up Outcomes After Surgery
ABSTRACT
Background
Uterine smooth muscle tumor of uncertain malignant potential (STUMP) is a rare “gray‐zone” entity characterized by unpredictable postoperative behavior and the absence of standardized surveillance strategies.
Objective
To describe postoperative clinical course, recurrence patterns, and fertility‐related outcomes in patients with STUMP managed at a tertiary center.
Methods
We conducted a retrospective observational study including 27 patients with a final pathology diagnosis of STUMP who underwent surgery and had postoperative follow‐up available between 2009 and 2025. Clinical, surgical, and pathological variables were collected from hospital records. Recurrence was defined as radiologic evidence of a new lesion during follow‐up and categorized by anatomic site. Outcomes included recurrence status, time to recurrence, recurrence histology, subsequent management, and pregnancy outcomes after uterus‐sparing surgery.
Results
Median follow‐up was 58 months (IQR 17–79; range 4–136). Recurrence occurred in six patients (22.2%), with a median time to recurrence of 36 months (IQR 8–66.3). Recurrences were local ( n = 4) or pulmonary ( n = 2); one patient with lung recurrence also had wrist soft‐tissue involvement. Histology at recurrence included leiomyosarcoma ( n = 2), STUMP ( n = 2), and leiomyoma ( n = 2). All recurrent cases underwent secondary surgery. One death occurred during follow‐up. Uterus‐sparing surgery was performed in nine patients (33.3%); recurrence occurred in four, all local. Two pregnancies were recorded, including one live birth.
Conclusion
STUMP shows heterogeneous postoperative behavior, including late and occasionally malignant or distant recurrences. Long‐term surveillance is warranted, and uterus‐sparing management may be considered in carefully selected patients with fertility goals under close follow‐up.