Benign metastasizing leiomyoma.

Benign metastasizing leiomyoma is a rare clinical entity that has been described in several previous reports. Although the exact pathophysiology of the disease is unknown, two predominant theories exist: (1) metastasis from an existing leiomyoma (commonly seen with uterine leiomyoma) or (2) multicentric leiomyomatous growths rather than actual metastases. We present an interesting case in which several elements of the patient's history complicated the differential diagnosis.