Benign metastasizing uterine leiomyoma with lymphatic and pulmonary metastases: a case report and literature review

BACKGROUND: Benign metastasizing leiomyoma (BML) is a rare disease usually observed in women of reproductive or premenopausal age with a history of uterine myomectomy or hysterectomy. The most common sites of metastases are the pulmonary, and other sites include heart, bones, liver, lymph nodes, bladder, skeletal muscles, and central nervous system. Here, we report a case of a 50 year-old woman with a history of hysterectomy who was initially suspected of uterine sarcoma but was finally confirmed to have BML with lung and lymph node metastases, and discuss the treatment and prognosis of BML. CASE PRESENTATION: A 50 year-old woman with a history of total abdominal hysterectomy presented with mild but persistent abdominal pain for more than 3 months. She was suspected of having uterine sarcoma before surgery and laparoscopic extensive debulking surgery including bilateral oophorectomy, pelvic and para-aortic lymph node dissection to the level of the left renal vein, and transcutaneous dissection of the right inguinal lymph nodes. Pathology confirmed a benign leiomyoma, and the patient was diagnosed with BML. No medication was administered after the surgery, and the follow-up was of no significance. CONCLUSION: Benign metastasizing leiomyoma (BML) is a rare disorder in which histologically benign smooth muscle tumors metastasize to extrauterine sites. Metastases are commonly observed in the lung, liver, lymph nodes, skin, bladder, esophagus, and skeletal muscles. BML is usually misdiagnosed as a malignant tumor before surgery until the pathology confirms its benign nature. However, this treatment remains controversial and undetermined. The prognosis is usually favorable owing to its benign nature.