Pulmonary benign metastasizing leiomyomas: a case series of 23 patients at a single facility

BACKGROUND: Pulmonary benign metastasizing leiomyoma (PBML) is a rare disease characterized by leiomyoma of benign histopathology existing in the lungs. Because of its rarity, limited literature with a single case or small number of cases has been regarding to the clinical course, pathology or management of PBML. METHODS: A retrospective study was performed of all PBML cases diagnosed and managed at Peking Union Medical College Hospital (PUMCH) from 2001 to 2019. The clinical characteristics, pathology, treatment and outcomes of each case were studied. RESULTS: There were 25 PBML patients identified in the 19-year period in PUMCH, and 23 patients’ data was analyzed. The median age at diagnosis was 46 years. There were 7 patients (30.4%) diagnosed with postmenopausal status. Two patients (8.7%) had no uterine leiomyoma, and 3 patients (13.0%) had no gynecologic surgery history. Immunohistochemistry of most lesions demonstrated positive for desmin, SMA and Estrogen/Progesterone Receptors; and negative for S-100 were shown in 7 cases. After curative or diagnostic surgeries for the PBML, several treatments from observation to medical or surgical castration were performed. Nine premenopausal patients preserved their ovaries at first. At a median follow-up of 8 years, 3 patients finally had oophorectomy. CONCLUSIONS: PBML is a rare disease and should be treated by individualization according to the patients’ age, symptoms and extent of lesion. Curative surgery for patients with limited lesions can achieve the complete response. For patients that are young and asymptomatic, close observation is recommended as the first choice. All patients should undergo long-term surveillance.