A 50–year–old woman with left breast cancer and a 10–pack–year smoking history presented to the emergency department with pleuritic right–sided chest pain and dyspnea. Six days earlier, she had undergone bilateral total mastectomy. She was neither febrile nor hypoxic. Blood pressure and pulse were normal. Her mastectomy surgical sites were without evidence of infection or bleeding. Lungs were clear. Breath sounds were decreased at the right base. Cardiac exam was normal. Extremity exam revealed minimal leg edema, equal bilaterally. A chest radiograph revealed cardiomegaly, interstitial edema, and right pleural effusion. Brain natriuretic peptide was within normal limits. Electrocardiogram was unremarkable. Echocardiography performed 1 month earlier had revealed normal ventricular dimensions and systolic function. She was given intravenous furosemide, with brisk diuresis and subjective improvement of her dyspnea and edema. Chest computed tomographic angiography revealed a small right pleural effusion, mild bibasilar atelectasis, and no evidence of pulmonary embolism or pneumonia. Also noted were a right apical pneumothorax and numerous, thin–walled cysts throughout both lungs, consistent with lymphangioleiomyomatosis (LAM). The chest radiograph report was later addended to include presence of a right apical pneumothorax which had not been noted in the preliminary findings. A chest tube was placed. The pneumothorax persisted despite chest tube drainage, necessitating eventual video–assisted thoracoscopic surgery and mechanical pleurodesis.
LAM is a rare disease of unknown etiology, with an estimated incidence of 1–2.6 cases per one million, affecting women almost exclusively. The pathology of LAM is represented by the proliferation of immature smooth muscle cells in the walls of lung airways, venules, and lymphatic vessels. Proliferation of these cells results in airway narrowing, obstruction, and air trapping, with eventual formation of cystic lung lesions. Spontaneous pneumothorax, often recurrent, is a characteristic finding of LAM. Smoking history and cyst morphology can help differentiate LAM from the other primary causes of cystic lung disease: emphysema and Langerhans cell histiocytosis. LAM follows an insidious course. The rate of disease progression ranges from a few years to several decades before culminating in respiratory failure. The combination of pleuritic chest pain and dyspnea is a symptom complex frequently encountered by hospitalists. While pneumothorax associated with LAM is an unexpected etiology of such symptoms, this diagnosis should be considered in a woman who presents with pneumothorax, cystic lung disease, and a nonexistent or minimal smoking history.
The purpose of reporting this case is to raise awareness of a rare condition, the presenting symptoms of which are frequently encountered by hospitalists and, therefore, may generate an initially restricted differential diagnosis.