Objectives: To evaluate comprehensively the characteristics of lymphangioleiomyomatosis (LAM), with emphasis on the application of imaging and immunohistochemical methods.
Design: Prospective study.
Patients: Thirty-five female subjects with LAM.
Setting: Clinical Center, National Institutes of Health.
Interventions: BAL, pulmonary function test, ventilation/perfusion lung scans, CT of the chest and abdomen, ultrasonography of abdomen, and immunohistochemical study of lung biopsy specimens.
Results: Most patients had exertional dyspnea (83%) and pneumothorax (69%). BAL did not show diagnostic changes. The most common abnormalities on pulmonary function tests were decreased diffusing capacity of carbon monoxide (83%), hypoxemia (57%), and airway obstruction (51%). Bronchodilator response was found in 26% of patients. CT, which is almost pathognomonic, showed numerous thin-walled cysts throughout both lungs in all patients. Thirty-four patients (97%) had abnormal ventilation and/or perfusion lung scans. An unusual "speckling" pattern was observed on ventilation scans of 74% of patients. Common extrapulmonary features were retroperitoneal adenopathy (77%) and renal angiomyolipomas (60%). The percentage of abnormal smooth muscle cells (LAM cells), reactive with HMB45, varied from 17 to 67% in 10 lung biopsy specimens.
Conclusions: Improved diagnostic methods have defined the abnormalities in patients with pulmonary LAM and increased the potential for early recognition and treatment of this disorder. Patients with LAM should be evaluated for bronchodilator responsiveness and may benefit from a trial of bronchodilators.