We studied 70 patients with biopsy-proven pulmonary non-Hodgkin's lymphomas without extrathoracic involvement or mediastinal adenopathy to determine the clinical, imaging, and endoscopic features of this condition in a homogeneous series. In low-grade (LG) lymphomas, symptoms were cough, dyspnea, chest pain, hemoptysis. Imaging features consisted of localized alveolar opacities, infiltrative diffuse opacities, atelectasis, and pleural effusions. Inflammatory changes of the mucosa were present in some patients, leading to bronchial stenosis in 7; biopsies showed lymphomatous infiltration in 12. Prognosis of LG lymphomas was excellent, with 93.6 percent survival at five years. High-grade lymphomas differed from LG lymphomas principally by a more aggressive course and a worse survival. Inflammatory changes occurred in seven of nine cases leading to stenosis in two, and biopsies showed lymphomatous involvement in five. The profile of primary pulmonary lymphomas in this study could help clinicians consider this condition and prompt them to evaluate new diagnostic tools.