Pulmonary lymphangioleiomyomatosis: unusual manifestations of multiple large pulmonary nodules with retroperitoneal lymph node involvement mimicking metastatic malignancy

Pulmonary lymphangioleiomyomatosis (LAM) is a rare, idiopathic disorder that predominantly affects the lung parenchyma of women of childbearing age. While the characteristic radiographic finding of pulmonary LAM consists of multiple well-defined thin-walled cysts, we describe a very unusual case of pulmonary LAM with multiple bilateral large pulmonary nodules and retroperitoneal involvement mimicking metastatic malignancy. A 48-year-old woman who had never smoked with a history of bilateral pneumothorax presented with progressive exertional dyspnea and abdominal discomfort. Imaging studies revealed multiple enlarged retroperitoneal lymph nodes, ascites and bilateral multiple large pulmonary nodules ranging from 3 to 18 mm in diameter. Exploratory laparoscopic surgery for intra-abdominal lesions and video-assisted thoracoscopic wedge resection of lung nodules were carried out to rule out metastatic malignancy. Pathology showed benign looking smooth muscle cell proliferation and immunoreactivity for α-smooth muscle actin and HMB-45 in both specimens. After treatment with GnRH antagonist, the patient was well over a 6-month period without evidence of disease progression.