BACKGROUND: Bronchioloalveolar carcinoma (BAC) has been reported to diveres spectrum of chinical presentations and radiologic patterns. The three representative radiologic patterns are followings; 1) a solitary nodule or mass, 2) a localized consolidation, and 3) multicentric or diffuse disease. While, the localized consolidation and solitary nodular patterns has favorable prognosis, the multicentric of diffuse pattern has worse prognosis regardless of treatment BAC presenting as a solitary pulmonary nodule is often misdiagnosed as other benign disease such as tuberculoma. Therefore it is very important to make proper diagnosis of BAC with solitary nodular pattern, since this pattern of BAC is usually curable with a surgical resection. METHODS: We reviewed the clinical and radiologic features of patients with pathologically-proven BAC with solitary nodular pattern from January 1995 to September 1996 at Samsung Medical Center. RESULTS: Total 11 patients were identified. 6 were men and 5 were women. Age ranged from 37 to 69. Median age was 60. Most patients with BAC with solitary nodular pattern were asymptomatic and were detected by incidental radiologic abnormality. The chest radiograph showed poorly defined opacity or nodule and computed tomography showed consolidation, ground glass appearance, internal bubble-like lucencies, air bronchogram, open bronchus sign, spiculated margin or pleural tag in most patients. The initial diagnosis on chest X-ray were pulmonary tuberculosis in 4 patients, benign nodule in 2 patients and malignant nodule in 5 patients. The FDG-positron emission tomogram was performed in eight patients. The FDG-PET revealed suggestive findings of malignancy in only 3 patients. The pathologic diagnosis was obtained by transbronchial lung biopsy in 1 patient, by CT guided percutaneous needle aspiration in 2 patients, and by lung biopsy via video-assited thoracocopy in 8 patients. Lobectomy was performed in all patients and postoperative pathologic staging were T1N0M0 in 8 patients and T2N0M0 in 3 patients. CONCLUSION: Patients of BAC presenting with solitary nodular pattern were most often asymptomatic and incidentally detected by radiologic abnormality. The chest X-ray showed poorly defined nodule or opacity and these findings were often regarded as benign lesion. If poorly nodule or opacity does not disappear on follow up chest X-ray, computed tomography should be performed. If consolidation, ground glass appearance, open bronchus sign, air bronchogram, internal bubble like lucency, pleural tag or spiculated margin are found on computed tomography, further diagnostic procedures, including open thoracotomy, should be performed to exclude the possiblity of BAC with solitary nodular pattern.