CT demonstration of calcification in carcinoma of the lung.

Abstract

Our goal was to assess the diagnostic significance of calcification in carcinoma of the lung, as seen on CT. We prospectively identified 500 consecutive patients with the provisional clinical diagnosis of lung cancer, who underwent CT examination of the chest from 1987 to 1991. Fifty-three (10.6%) of the 500 CT examinations revealed intratumoral calcification. When these 53 patients were reviewed retrospectively in 1992, CT examinations were available for 39, each with microscopic proof of primary carcinoma of the lung. Tumors were assessed for histologic subtype, size, and location and compared with a control group of the last 115 noncalcified, proven, primary carcinomas of the lung in the series. Intratumoral calcification seen on chest CT was assessed for location, extent, and pattern. The calcified tumors tended to be large (6.2 +/- 3.0 cm, mean diameter +/- SD) compared with the noncalcified tumors (4.4 +/- 2.3 cm) (p = 0.0001). The calcified tumors were central in 28 (72%) and peripheral in 11 (28%) patients. The noncalcified tumors were central in 52 (45%) and peripheral in 63 (55%) patients (p = 0.007). Punctate pattern of calcification correlated marginally with small cell carcinoma (p = 0.07). Histologic subtype showed no correlation with intratumoral location or extent of calcification. Calcification is identified in 10% of lung cancer, does not predict histologic subtype, and tends to occur in large, central tumors.