Pulmonary benign metastasizing leiomyoma: a case report and literature review

Benign metastasizing leiomyoma (BML) is a rare condition that occurs mainly in premenopausal women and is characterized most commonly by pulmonary metastases. Here, we report the case of a 45-year-old woman who presented with multiple bilateral pulmonary nodules on chest examination during a health checkup 13 years after myomectomy. This patient has a normal menstrual cycle, moderate anemia, and no obvious respiratory symptoms. Serum concentrations of cancer markers such as carcinoembryonic antigen, neuron specific enolase, cytokeratin 19 fragments, and pro-gastrin-releasing peptide were within normal limits. Color doppler ultrasound was also performed, several hypoechoic regions were found in uterine bodies and cavity. The computed tomography (CT)-guided lung biopsy was used for histopathological examination. Immunohistochemical staining revealed BML which were positive for smooth muscle antibody, desmin, vimentin, estrogen and progesterone receptors, and Ki-67 positive rate of about 1%. Hysterectomy and bilateral adnexectomy were performed as a part of treatment. The lung nodules were meticulously monitored at follow-up. Three months later, the repeat CT scan showed that the nodules had reduced in size, and no new nodules had appeared, 1 year later, CT scan showed no obvious changes in lung nodules. This study is of great significance as the results will be helpful in diagnosing and treating future pulmonary benign metastasizing leiomyoma (PBML) cases.