UC Irvine

Benign metastasizing leiomyomas (BML) represent a rare phenomenon consisting of the extra-uterine spread of smooth muscle cells with similar histological, immunological, and molecular patterns to those of benign uterine leiomyomas. They are considered benign based off their low mitotic activity, lack of anaplasia or necrosis, and limited vascularization. This condition represents an interesting diagnostic and treatment challenge based on their rarity and indolent nature. Our case represents a unique finding of BML in the thoracic spine in a postmenopausal woman many years after hysterectomy and partial oophorectomy. There are currently no standard guidelines for treatment of BML, given the rare nature of this condition, with most patients treated with a combination of surgical resection and radiotherapy, followed by hormonal treatment and radiological surveillance serving as the primary backbone of current management plans. Given that these patients present a unique clinical challenge in terms of diagnosis and management, it is important to delineate and further examine these rare entities.