Multiple cavitating pulmonary nodules: rare manifestation of benign metastatic leiomyoma

Benign metastasizing leiomyoma (BML) is a rare disease of pathologically benign, but the tumor metastasizes to other organs. The most common organ involved in BML is lung. Pulmonary involvement usually manifested as multiple nodules on chest X-ray, however we experienced an interesting case of a 52-year-old premenopausal woman who presented with multiple bilateral lung cavitations and nodules on a chest X-ray without any respiratory symptoms. Chest computed-tomography identified multiple cavitary lesions of 5-12 mm in diameter and well-defined nodules of 5-10 mm in diameter in both lung fields. Transthoracic needle biopsy was performed and the resected lesion consisted of benign spindle cells was positive for estrogen receptor (ER) and progesterone receptor (PR) and was diffuse positive for actin and desmin by immunohistochemical (IHC) staining, suggesting leiomyoma. The final diagnosis was benign pulmonary metastasizing leiomyoma (BPML) and the patient underwent subcutaneous injection of a gonadotrophin releasing hormone (GnRH) agonist for 12 months, follow-up low-dose chest computed tomography (CT) scan at 15 months revealed decreased cavitations and nodular lesions. We should take into consideration the possibility of BPML when we encounter multiple cystic or cavitary lesions on chest X-ray, although the common form of BPML is nodulary lesions on imaging studies.