Ground-glass opacity on thin-section CT: Value in differentiating subtypes of adenocarcinoma of the lung

Abstract

OBJECTIVE. The purpose of this study was to determine whether thin- section CT could be used to differentiate small localized bronchioloalveolar carcinoma from peripheral adenocarcinoma having a bronchioloalveolar (replacement) growth pattern of alveolar lining cells and from adenocarcinoma not having a replacement growth pattern on the basis of the extent of ground- glass opacity revealed by thin-section CT. MATERIALS AND METHODS. One hundred twenty-four small, surgically resected, peripheral adenocarcinomas from 119 patients (67 men and 52 women; mean age, 60 years) were studied. Lesion diameters were 0.4-2.0 cm (median, 1.5 cm). The extent of ground-glass opacity within lesions on preoperative thin-section CT was reviewed retrospectively by three thoracic radiologists. On the basis of replacement growth of alveolar lining cells, small adenocarcinomas were classified histologically as localized bronchioloalveolar carcinomas (n = 42) or as adenocarcinomas with (n = 53) or without (n = 29) a replacement growth pattern of alveolar lining cells. RESULTS. The percentage of lesions that had ground-glass opacity was significantly greater in localized bronchioloalveolar carcinomas (mean, 56.7% ± 33.0%) than in adenocarcinomas with a replacement growth pattern (mean, 26.3% ± 25.3%, p < .001) or in adenocarcinomas without a replacement growth pattern (mean, 8.3% ± 4.7%, p < .001). CONCLUSION. Determination of the ground-glass opacity area in each tumor as revealed on thin-section CT was useful for differentiating small localized bronchioloalveolar carcinomas from small adenocarcinomas not having a replacement growth pattern.