Pulmonary benign metastasizing leiomyoma (BML), is characterized by multiple pulmonary nodular lesions and is a rare disease. The present study reports the case of a 45-year-old asymptomatic woman who underwent an excision of uterine leiomyoma 11 years previously. Chest computed tomography (CT) revealed multiple bilateral pulmonary nodules five months prior to admission, during a regular check-up. Intravenous levofloxacin (0.5 g/day) was administered for one week, which demonstrated no effect. Positron emission tomography combined with CT (PET/CT) revealed no evident radioactivity concentration. Due to the suspicion of metastasizing leiomyoma, video-assisted thoracoscopic surgery, with a wedge resection of the right pulmonary lesion, was performed. Post-operative pathological examination revealed the lesion to be a pulmonary leiomyoma accompanied by local necrosis. Immunohistochemical staining revealed that the lesion was positive for the expression of smooth muscle actin, desmin, estrogen receptor, progesterone receptor and B-cell lymphoma-2. Cytokeratin and epithelial membrane antigen were not expressed in the tumor cells. Staining for Ki-67 revealed expression of Ki-67 in ~1% of the spindle cells. The overall morphological and immunohistochemical features, accompanied by the remote patient history of primary uterine leiomyoma, supported the diagnosis of pulmonary BML.
Keywords: benign lesion; histological origin; leiomyoma; lung.