Benign metastasizing leiomyoma with retroperitoneal lymph node involvement in a patient with a history of renal cell carcinoma.

Benign metastasizing leiomyoma (BML) is thought to arise from either coelomic metaplasia of mesenchymal tissue or peritoneal seeding of uterine fibroid tissue, though its exact etiology is unknown. Herein, we present a 44-year-old Hispanic female with BML identified in the retroperitoneum in the setting of clear cell renal carcinoma. Routine follow-up computed tomography scan, 18 months after a robotic left partial nephrectomy for stage 1 renal tumor, revealed retroperitoneal (para-aortic) adenopathy. Percutaneous biopsy followed by robotic lymph node dissection confirmed the presence of BML. The patient remained asymptomatic with unremarkable imaging and laboratories within a 3-year follow-up.