Pulmonary benign metastasizing uterine leiomyoma (PBML): a case report and review of the literature

Benign metastasizing leiomyoma (BML) is a rare disorder characterized by the presence of benign smooth muscle tumours in extrauterine sites, typically the lungs. It classically involves perimenopausal women with a history of uterine surgery. The condition follows an indolent course but may cause clinical symptoms with large or widespread lesions.

Case presentation: The authors report the case of a 47-year-old female who presented with a 6-month history of irregular vaginal bleeding and severe hot flushes. The patient had no previous history of gynaecological surgery. Ultrasonography and subsequent MRI identified a suspicious 105×65 mm mass involving the right uterine cornu and broad ligament. Computed tomography identified bilateral lung nodules, suspicious for metastases. Histological assessment of the final uterine surgical specimen identified a benign dissecting leiomyoma involving the broad ligament and cervix. BML was diagnosed after thoracoscopic resection of a lung lesion which revealed a histologically identical tumour with entrapped normal lung alveoli.

Clinical discussion: This case shows that there is a minority of patients without previous uterine surgery who still go on to develop pulmonary BML. In our case, a combined treatment approach was adopted, involving substitution of hormone replacement therapy to a non-hormonal alternative, thoracoscopic resection of lung lesions and interval surveillance imaging of the chest.

Conclusions: BML is a rare condition but should be considered as a differential in women with pulmonary nodules and a history of uterine leiomyomata. Its diagnosis and subsequent counselling can be challenging; therefore cases should be treated by multidisciplinary teams in tertiary specialized centres.