Abstract Introduction Benign Metastasizing Leiomyoma is an exceptionally rare disease characterized by the systemic dissemination of histologically benign smooth muscle tissue originating from uterine leiomyomas. The lungs are the most common site of metastasis, presenting as multiple bilateral pulmonary nodules. The following describes a case of a 47-year-old female whose workup for shortness of breath led to the diagnosis of benign metastasizing leiomyoma. Case A 47-year-old female with a history significant for uterine leiomyoma requiring myomectomy, presented for follow-up evaluation concerning persistent shortness of breath on exertion. To determine the etiology of her pulmonary symptoms, the patient underwent flexible bronchoscopy, fine-needle aspiration, and a right video-assisted thoracoscopy (VATS) with lung biopsy. The pathology was highly significant, returning positive for a low-grade spindle cell neoplasm with muscle differentiation, favoring benign metastasizing leiomyoma. Subsequent MRI of the pelvis confirmed multiple uterine fibroids, the largest measuring 3.5 × 3.2 cm, which were Estrogen Receptor positive. The patient was initiated on goserelin and letrozole while awaiting definitive surgery. The patient underwent total hysterectomy and bilateral salpingo-oophorectomy. On exam, patient had continued shortness of breath, which improved with rescue inhaler. Plans for potential thoracic surgery, pending clinical improvement. Discussion Benign Metastasizing Leiomyoma is a critical differential diagnosis for pulmonary nodules in women with a history of uterine leiomyomas. The primary pulmonary symptom, dyspnea, resulted from the parenchymal bulk of the metastatic nodules. While the term “metastasizing” implies malignancy, the pathology is benign, however the respiratory morbidity can be significant. There is a need for prompt diagnosis via lung biopsy, and dual-phase therapeutic approach, which involves definitive surgical excision of the primary uterine tumor coupled with long-term hormonal suppression to manage the metastatic pulmonary disease. This case underscores the need to maintain a high index of suspicion for benign metastasizing leiomyoma in the differential for pulmonary nodules in premenopausal women with a history of uterine leiomyomas, even years after the initial surgical intervention. This abstract is funded by: None
Sculthorpe et al. (Fri,) studied this question.