[Bronchiolo-alveolar carcinoma. The computed tomographic picture and histological correlations]

Twenty-one CT examinations of 18 patients with a known bronchioloalveolar carcinoma in the lung were retrospectively reviewed to describe the CT features of bronchioloalveolar carcinomas. Surgical specimens were available in 13 cases in which CT-histologic correlation was also obtained. In 5 patients the diagnosis was made with cytology and confirmed with radiologic-clinical follow-up. Three patients were reexamined for relapses 6-20 months after the resection of a localized carcinoma. Carcinomas exhibited 3 radiologic patterns: a) solitary pulmonary nodule (11 cases), b) mass or pulmonary consolidation (3 cases) and c) multicentric or diffuse disease (7 cases). Solitary nodular bronchioloalveolar carcinomas were associated with irregular or spiculated margins in 9 of 11 patients. In some cases internal inhomogeneity due to bubble-like radiolucencies was demonstrated. At pathology, bubble-like radiolucencies correlated with air-containing cystic spaces lined by neoplastic epithelium or patent and dilated bronchi. Some nodules exhibited linear and serpentine internal radiolucencies. Pathology demonstrated them to be consistent with patent intratumoral bronchioles (air bronchiologram) and air-containing neoplastic glandular spaces, respectively. In two cases a perinodular ground-glass halo was demonstrated surrounding the nodule (CT halo sign), due to perinodular lepidic tumor growth. Massive or ground-glass opacity involving a pulmonary segment or a lobe was another CT pattern of bronchioloalveolar carcinoma. An air bronchogram was usually demonstrated within the lesion. In the mucinous type of bronchioloalveolar carcinoma, pulmonary consolidations had a low CT value because of the large amount of intratumoral mucus. The diffuse type of tumor presented as multiple pulmonary nodules or multiple pulmonary consolidations, or both. In two cases multiple nodules were associated with carcinomatous lymphangitis. In conclusion, bronchioloalveolar carcinoma should be considered in the differential diagnosis of solitary pulmonary nodules, multiple pulmonary nodules and chronic alveolar opacities. The diagnosis of a bronchioloalveolar carcinoma is of great value since surgery can help nearly 70% of the patients at this stage recover.