PURPOSE: The purpose of this study is to describe the characteristic high-resolution(HR) Ct findings ofsolitary nodular bronchioloalveolar carcinoma(BAC) of the lung which are valuable for specific diagnosis of thedisease. MATERIALS AND METHODS: HRCT scans of 46 patients (31 with malignant and 15 with benign lesion) with asolitary pulmonary nodule seen on chest radiograph were distributed in random order and analyzed retrospectively.Two blinded observers jointly analyzed the marginal and internal characteristics of nodules as seen on HRCT, anddecisions on the findings were reached by consensus. Stepwise discriminant analysis for characteristic findings ofBAC was performed. RESULTS: The most frequent CT findings of BAC (n=15) were internal bubble lucency (14/15,93%)(p=0.001), area of ground-glass opacity (12/15, 80%;average 58% of tumor volume)(p=0.0001), pleural tag(12/15,80%;p=0/097), and lobulated and spiculated margin(8/15, 53%;p=0.459). Findings of ground-glass opacity(p=0.0001)and bubble lucency(p=0.0187) appeared to be discriminantin the diagnosis of BAC. CONCLUSION: Peripheral pulmonarynodules containing an area of ground-glass opacity associated with internal bubble-lucency are characteristic ofBAC. Specific histologic diagnosis of solitary nodular BAC can be suggested by careful analysis of HRCT findings.