BENIGN METASTASIZING LEIOMYOMA

SESSION TITLE: Diffuse Lung Disease Case Report Posters 3 SESSION TYPE: Case Report Posters PRESENTED ON: 10/09/2023 12:00 pm - 12:45 pm INTRODUCTION: Benign metastasizing leiomyoma (BML) is a rare condition in which benign uterine leiomyomas (fibroids) migrate to distant organs, such as lungs and lymph nodes, and form multiple nodules that mimic metastatic tumors. Typically lesions are composed of smooth muscle cells. Imaging and biopsy are required to make a formal diagnosis. Despite being histologically benign, BML can present with symptoms and radiographic findings that are indistinguishable from malignant disease, making accurate diagnosis and management challenging.Most women are diagnosed with BML before menopause. Histopathopathology will show spindle cells without any atypia, high mitotic rate, or tumor necrosis. The exact mechanism of BML development and progression is still unclear, but it is believed to involve hormonal and genetic factors. Currently, no guidelines exist for treatment and the focus remains on surgical resection of the lesions. However, there are emerging hormonal therapies, which are available on an individual basis. CASE PRESENTATION: We present a case of a 32-year-old female with a history of uterine fibroids and childhood asthma admitted to the hospital for acute onset of severe left-sided chest pain and shoulder and back pain. Previously she had multiple hospitalizations for pneumothoraces status post chest tube and pleurodesis. She underwent a left upper long wedge lung biopsy for pulmonary nodules seen on the CT chest without contrast. Imaging showed chain suture material within the left lung apex measuring 2.4 cm x 3.2 cm. Biopsy showed patchy nodular and interstitial spindle cell proliferation in all sections. In most places, spindle cells merge into surrounding parenchyma without a discrete margin. Spindle cell proliferation in those areas is more primitive. Focal hemosiderin depositions are seen. Immuno-staining of the spindle cells showed estrogen, progesterone, and smooth muscle actin-desmin positive, while HMB45, CD34, D2-40, and melanA negative. DISCUSSION: BML typically occurs in premenopausal women with a history of uterine leiomyomas or fibroids. The most common presenting symptom is shortness of breath. Other symptoms may include chest pain, cough, and hemoptysis. Imaging studies such as chest X-ray, CT scan, or MRI are usually used to evaluate lung nodules, which can appear as multiple, well-defined nodules with a characteristic appearance on imaging. Histologically, BML nodules are composed of benign smooth muscle cells, similar to uterine leiomyomas. Treatment for BML is controversial, as there is no consensus on the optimal management strategy. Some experts recommend close monitoring and observation, while others advocate for surgical resection or hormonal therapy. The decision to intervene depends on the patient's symptoms, the number and size of nodules, and the potential for growth and complications. After extensive discussion with the tumor board, leuprolide was not indicated for our patient. Instead, she was continued on norethindrone as needed for birth control and close follow-up with pulmonology and gynecology. CONCLUSIONS: In conclusion, BML is a rare condition that can mimic metastatic disease and present a diagnostic challenge. Accurate diagnosis and management require a multidisciplinary approach involving clinicians, pathologists, and radiologists. Further research is needed to understand the underlying mechanisms of BML and to develop effective treatment strategies for affected individuals. REFERENCE #1: Barnaś E, Książek M, Raś R, Skręt A, Skręt- Magierło J, Dmoch- Gajzlerska E. Benign metastasizing leiomyoma: A review of current literature in respect to the time and type of previous gynecological surgery. PLOS ONE. 2017;12(4). doi:10.1371/journal.pone.0175875 REFERENCE #2: E W. Benign metastasizing uterine leiomyoma: Case report with review of the literature. Cytology & Histology International Journal. 2020;4(1):1-5. doi:10.23880/chij-16000117 REFERENCE #3: Fan R, Feng F, Yang H, et al. Pulmonary benign metastasizing leiomyomas: A case series of 23 patients at a single facility. BMC Pulmonary Medicine. 2020;20(1). doi:10.1186/s12890-020-01330-4 DISCLOSURES: No relevant relationships by Timothy DAmico No relevant relationships by Ronak Patel No relevant relationships by Robyn Scatena