Uterine smooth muscle tumors of uncertain malignant potential (STUMP) are rare mesenchymal tumors with characteristics between benign leiomyomas and leiomyosarcomas (LMSs). Diagnosis, surgical management, and follow-up of this neoplasm remain controversial due to their unaggressive behavior and prolonged patient survival rate compared to LMSs. However, recurrence is estimated at almost 10% and may include delayed recurrences. When morcellated uterine tumors are unexpectedly found to be LMSs or tumors with atypical features (atypical leiomyoma, smooth muscle tumors of uncertain malignant potential), there may be significant clinical consequences.
We report the case of a 49-year-old woman (gravida 2, para 2) who presented with recurrence and transformation into LMS 37 months after the first operation without morcellation for STUMP.
The patient had undergone a total laparoscopic hysterectomy and bilateral salpingo-oophorectomy without morcellation for a suspected uterine myoma, which was histologically proven to be STUMP. The patient presented with two months of dull pain on her right back buttock. Computed tomography showed a relapse of STUMP at the right side of the vaginal stump to pelvic wall and right hydronephrosis. The patient underwent a laparotomy for complete removal of the neoplastic recurrence and removal of the right kidney and ureter, which was histologically proven to be recurrence and transformation into LMS. The patient received adjuvant gemcitabine plus docetaxel. To date, the patient is disease-free.
STUMP needs frequent surveillance for the risk of recurrence and transformation into LMS, even many years after the first diagnosis and even after complete removal without morcellation.