INTRODUCTION: Benign metastasizing leiomyomatosis (BML) is a rare condition that usually affects women with a history of uterine leiomyomatosis who have undergone a hysterectomy. It is characterized by multiple, benign, slow growing, smooth-muscle tumors outside the uterus. The lungs are the most common site of metastasis.
CASE PRESENTATION: We report the case of a 41-year-old African American woman with a history of uterine arterial embolization (UAE) at age 38 for the treatment of uterine leiomyomatosis. The patient was referred to the pulmonary clinic after the incidental discovery of multiple right lower lobe nodules on an abdominal computed tomography (CT) scan ordered for the evaluation of abdominal pain and constipation. A dedicated chest CT showed small, bilateral pulmonary nodules from 2-13mm in diameter. On review of systems, the patient complained of a non-productive cough for about a year, which had been attributed to gastric reflux and nasal rhinitis. Otherwise, she was asymptomatic. She had no other significant past medical history and no history of occupational exposures. She had lived in areas that were endemic for histoplasmosis and coccidiomyocosis, but urine histoplasmosis antigen and serum coccidiomyocosis titers were within normal limits. A complete blood count, liver function panel, and serum chemistries were also unremarkable. A whole body positron emission tomography scan demonstrated no increased fluorodeoxyglucose uptake in the lesions. The patient underwent a CT guided biopsy, which showed bundles of benign smooth muscle cells. The histopathology and immunohistochemical stains were consistent with metastasis of the patient's benign uterine leiomyoma. Surgical castration and hormonal therapy were recommended. However, the patient was relatively asymptomatic and has not yet consented to either. She has been closely followed for clinical or radiographic evidence of disease progression.
DISCUSSIONS: Benign Metastasizing Leiomyomatosis (BML) is a rare condition that is characterized by the presence of multiple, indolent, smooth muscle tumors in the lung. It is thought to be the result of hematogenous spread of a benign primary uterine leiomyoma. Because BML usually occurs months to years after hysterectomy, it is theorized that the tumor cells may enter the blood stream during the trauma of surgery and disseminate. Most patients with BML are minimally symptomatic, but patients can have significant chest pain, dyspnea, and cough. The tumors tend to be hormonally sensitive. There have been reports of successful treatment with surgical castration, progesterone, gonadotropin releasing hormone analogues, aromatase inhibitors, luteinizing hormone releasing hormone agonists, and selective estrogen receptor modulators. In recent years, uterine arterial embolization has gained popularity as a minimally-invasive option for the treatment of uterine leiomyomatosis. To our knowledge, this represents the first reported case of BML in a patient who has undergone UAE.
CONCLUSION: BML is a rare condition whereby benign uterine leiomyomas metastasize to sites outside the uterus. It usually occurs after hysterectomy. The tumors tend to be indolent and hormonally responsive. UAE has become a popular alternative to hysterectomy for the treatment of uterine leiomyomatosis. We report the first case of BML after UAE. Physicians should be aware that there is a potential relationship between UAE and BML. As such, the diagnosis of post-UAE BML should be considered in the appropriate clinical setting.
DISCLOSURE: Joshua Sill, None.