Twenty-one patients presenting with extrapulmonary sarcoidosis, 20 patients with pulmonary sarcoidosis, and 12 healthy volunteers were investigated. They were evaluated for roentgenographic findings, as well as for immunologic marker expression of cells in bronchoalveolar lavage (BAL) fluid. The patients presenting with extrapulmonary sarcoidosis could be divided in two groups: nine of 21 (43 percent) presented with a stage 1 or stage 2 chest x-ray film, while 12 of 21 (57 percent) had no chest x-ray film abnormalities (stage 0). In all three groups of sarcoidosis patients, a significant increase of CD3+ T lymphocytes in the BAL fluid was found as compared to the healthy volunteers. However, the percentages of T lymphocytes in BAL fluid of patients with extrapulmonary sarcoid lesions and a normal (stage 0) chest x-ray film was significantly lower as compared to patients with extrapulmonary sarcoidosis and an abnormal (stage 1, 2) chest x-ray film, while the latter patient group did not differ from the patients with pulmonary sarcoidosis. This suggests that in patients with extrapulmonary sarcoidosis, a gradual progression of the T cell alveolitis may occur. Furthermore, these data indicate that a marked discrepancy between chest x-ray film abnormalities and the presence of an alveolitis as determined by immunologic marker analysis exists in more than 50 percent of the patients with extrapulmonary sarcoidosis.