Metastatic bronchopulmonary leiomyosarcoma: A rare progression of benign disease.

Uterine leiomyosarcomas (U-LMS) are rare tumors, accounting for about 1% of all uterine malignancies that occur in varying age groups and have presented as both primary as well as metastatic disease from alternative sites. We present a rare case of uterine leiomyosarcoma presenting as a bronchial mass. A 61 year old African-American female presented with a five day history of worsening shortness of breath and blood tinged sputum. Her dyspnea was initially only with significant exertion but in the past two weeks worsened and occurred with only slight movement. She also reported several months of fatigue and a thirty-pound weight loss during that time. She denied any chest pain, palpitations or leg swelling. Three years prior to preentaiton, she underwent a total abdominal hysterectomy/bilateral salpingo-oophorectomy secondary to fibroid uterus. Pathology was consistent with atypical cellular leiomyoma. CT scan revealed a right lower lobe mass extending into the right hilum with obstruction of the right bronchus intermedius and mediastinal pathologic lymphadenopathy. Flexible bronchoscopy revealed a white tumor completely obstructing the bronchus intermedius. Rigid bronchoscopy was subsequently performed with electrocautery and mechanical debulking. The endobronchial mass was found to be smooth surfaced with a necrotic center. Intraoperative pathology was reported to be of spindle cell origin, suggestive of leiomyoma, but not definitive on frozen section. She was seen within a month of discharge after final pathology of the lung lesions was diagnosed as metastatic low grade leiomyosarcoma. Staging CT of the abdomen and pelvis revealed a pelvic mass in the location of the previously resected uterus. She completed one cycle of chemotherapy with gemcitabine and docetaxel. However, she was subsequently readmitted for sepsis leading to PEA arrest. She expired after family elected to withdraw care. Leiomyosarcomas are rare (1-2% of all uterine malignancies) and usually present with abdominal pain, enlarged abdominal circumference, enlarged uterine size and vaginal bleeding. U-LMSs presenting following removal of benign leiomyomas are even rarer, cited to be about 0.25%. There is also controversy regarding the feasibility of malignant transformation of benign leiomyomas. This case is unique in that the patient was not diagnosed with a primary uterine leiomyosarcoma even by histology at the time of hysterectomy and remained symptom free until airway compromise from the pulmonary lesion. While this tumor often develops distant metastases, including the lung (67%), it is far less common for a leiomyosarcoma to present as a lung lesion several years following benign hysterectomy