[A case of benign metastasizing leiomyoma medicating for 14 years]

We report a case of benign metastasizing leiomyoma medicated for 14 years after the diagnosis. A 47-year-old woman, who had undergone hysterectomy for uterine myoma at age 40 in 1989, was readmitted in 1996 because of abnormal shadows found on a chest X-ray film. Computed tomography (CT) and further chest X-ray films showed multiple nodules in bilateral lung fields. Open lung biopsy revealed leiomyomatous nodules histologically similar to those found at age 40. Tests for both estrogen and progesterone receptors in the biopsied specimen were positive. We diagnosed the lung nodules as benign metastasizing leiomyoma (BML) and gave her progesterone. Apart from 2 occasions when the patient elected to stop receiving medication, we obtained decreases in the size and number of tumors for 10 years from the start of treatment. However, despite continued administration of progesterone, the tumors continued to grow slowly during the next 4 years. We believe that the effectiveness of progesterone may have gradually decreased in this case, and thus are considering a change in treatment. BML is rare, and it must be carefully followed up long-term in post-menopausal patients.