Pulmonary benign metastasizing leiomyoma in patients aged 45 years and younger: clinical features and novelty in treatment

Background: Pulmonary benign metastasizing leiomyoma (PBML) is the most common extrauterine spread of uterine leiomyoma and its biological behavior is traditionally thought to be hormone-dependent. Studies about the older PBML patients has been previously reported, but limited literature has been regarding to the clinical features and treatment of PBML in young women. Methods: : A total of 65 cases of PBML in women aged 45 years and younger were reviewed, including 56 cases selected from PubMed and 9 cases from our hospital. The clinical characteristics and management of these patients were analyzed. Results: : The median age of all the patients at diagnosis was 39.0 years. PBML most commonly presented as bilateral solid lesions (60.9%), with other rare imaging manifestations. Median interval time from a pertinent gynecologic procedure to diagnosis was 6.0 years. 16.7% of patients received careful observation and all achieved stable status in a median follow-up time of 18.0 months. 71.4% of patients were administrated anti-estrogen therapies, including surgical castration (33.3%), gonadotropin-releasing hormone analogue (23.8%) and anti-estrogen drugs (14.3%). Eight of 42 patients underwent surgical resection of metastatic lesions. Patients receiving curative surgery for the removal of pulmonary lesions, combined with adjuvant anti-estrogen therapies, had favorable outcomes compared with the ones who only received surgical resection. The disease control rates of surgical castration, gonadotropin-releasing hormone analogue, anti-estrogen drugs were 85.7%, 90.0%, 50.0%, respectively. Rapamycin for two patients achieved successful relief of symptoms and control of pulmonary lesions without lowering hormone levels and causing estrogen deficiency symptoms. Conclusions: : In the absence of standard treatment guidelines for PBML, maintaining a low-estrogen environment by different kinds of anti-estrogen therapies has been the mainstream strategy currently and has satisfying curative effects. A wait-and-see strategy might be an option, but therapeutic approaches must be contemplated when complications or symptoms progressed. For PBML in young women, the negative effect on ovarian function of anti-estrogen treatment especially surgical castration should be considered. Rapamycin might be a new treatment option for young PBML patients, especially for those ones who want to preserve ovarian function.