Benign metastasizing leiomyoma of the lung. Report of a case

Benign metastasizing leiomyoma (BML) is the term used to describe multiple benign pulmonary leiomyomatous lesions occurring in patients with a previous history of uterine leiomyoma. On the other hand, pulmonary fibroleiomyomatous hamartoma (FLH) is also multiple nodules and the discrimination of the nodules between BML and FLH is not determined. We report the case of 36-year-old woman who had a previous history of uterine leiomyoma. The woman was referred to our hospital for evaluation of asymptomatic bilateral nodules in chest roentgenogram examination. A chest X-ray showed multiple nodules in bilateral lung. Chest computed tomography (CT) scan showed round nodules well-defined margins in bilateral lung. Thoracoscopic partial resection of the lung was performed. Pathological examination revealed that the tumor composed of spindle-shaped smooth muscle cells and its characteristics were remarkably similar to those of the previously resected uterine leiomyoma. Therefore, these lung tumors could be considered to be lung metastases from a uterine leiomyoma (benign metastasizing leiomyoma).