Primary ovarian leiomyosarcoma (POLMS) is an extremely rare ovarian malignancy, accounting for 0.1% of ovarian cancers. It typically presents as a unilateral large solid pelvic mass, often with pressure symptoms, and carries a poor prognosis, with a 5-year survival rate of approximately 20%. Proper surgical intervention is essential, and diagnostic challenges are frequent due to its rarity.

A 42-year-old woman presented with abdominal distension, subcutaneous nodules, and breast masses 3 years after undergoing a TAH with BSO for a large ovarian mass initially diagnosed as a benign cellular leiomyoma. Imaging revealed a massive abdominopelvic tumor (30 × 20 cm) with multiple metastasis. Core biopsies of the pelvic and breast masses confirmed leiomyosarcoma. Chemotherapy with doxorubicin followed by a docetaxel-gemcitabine regimen yielded partial response, including reduction in the abdominal mass and resolution of subcutaneous nodules.

A review of 26 reported cases of POLMS highlights diagnostic challenges and frequent misclassification as benign leiomyomas. POLMS often presents with late-stage disease and high recurrence rates, especially in advanced stages (IC and IIIC). Management strategies remain inconsistent, with varied chemotherapeutic regimens including gemcitabine- and doxorubicin-based protocols.

The rarity and diagnostic difficulty of POLMS underscore the need for comprehensive preoperative evaluation of ovarian masses, especially when malignancy is suspected.