Two cases of pulmonary benign metastasizing leiomyoma

Abstract

Background. Benign metastasizing leiomyoma (BML) is a rare entity in which a benign uterine leiomyoma causes metastasis to the lung. Herein, we report 2 cases of BML and review the previous literature. Case 1. A 52-year-old woman was identified as having multiple lung tumors during a preoperative examination for uterine leiomyoma. After hysterectomy, she underwent thoracoscopic resection of the tumor. The histological diagnosis was BML, and immunohistochemical staining was positive for estrogen receptor but negative for progesterone receptor. The patient received hormonal therapy for 7 months after the surgery. At 11 years after the surgery, we observed a slowly growing tumor in the right upper lobe. Case 2. A 51-year-old woman who underwent hysterectomy for uterine leiomyoma was identified as having multiple lung tumors, during a medical check-up. She underwent thoracoscopic resection of the tumor, and was diagnosed with BML. Immunohistochemical staining revealed that the tumor cells were positive for estrogen and progesterone receptors. The patient did not receive hormonal therapy, and no changes in the tumors were noted at 6 months after surgery.