A Case of Pulmonary Benign Metastasizing Leiomyoma Presented with Pulmonary Metastases of Thyroid Cancer

Abstract

Benign metastasizing leiomyoma (BML) is a rare disease where uterine leiomyomas most frequently metastasize to the lungs. Here, we present a case of BML in a 67-year-old woman who underwent hysterectomy at the age of 36 for uterine leiomyomas and thyroidectomy at 40 for thyroid cancer. Bilateral multiple lung nodules developed, which were initially considered as lung metastases of thyroid cancer, and the patient had been followed-up for about 27 years after thyroid surgery. Despite being asymptomatic, a partial enlargement of one lung nodule prompted the performance of a video-assisted thoracoscopic left lung biopsy for diagnostic confirmation and further management. Pathological examination revealed spindle-shaped cells without atypia, and immunohistochemistry demonstrated estrogen and progesterone receptor positivity, leading to the diagnosis of BML in the lungs. In cases of bilateral multiple lung nodules in women with a history of uterine leiomyomas, BML should be considered.