Low-Grade and High-Grade Mucoepidermoid Carcinoma of the Lung: CT Findings and Clinical Features of 17 Cases

Abstract

OBJECTIVE. The objective of our study was to characterize the CT features and clinical findings of low-grade and high-grade mucoepidermoid carcinoma (MEC) of the lung. MATERIALS AND METHODS. The CT findings and clinical information of 17 consecutive patients with primary low-grade (n = 11) or high-grade (n = 6) MEC were analyzed retrospectively. We assessed tumor location, size, contour, margin, density, calcification, obstructive changes, presence of metastasis, and enhancement. RESULTS. In patients with low-grade MEC, tumor location was central in 10 and peripheral in one. In contrast, one and five tumors in patients with high-grade MEC were central and peripheral, respectively. There was a significant difference between central and peripheral locations among tumor grades (p = 0.005). In low-grade MECs, tumor contour was smoothly oval (n = 3) or spheric (n = 4); four were lobular. In five patients with low-grade MEC, tumors had well-defined margins; margins in the other six were poorly defined. Tumor density was homogeneous and heterogeneous in eight and three low-grade tumors, respectively. All six high-grade tumors had heterogeneous density, lobular contours, and poorly defined margins. Enhancement in both low-grade and high-grade tumors was greater than that of chest wall muscles, and low-grade tumors showed greater enhancement (46.90 ± 20.44 HU) than did high-grade tumors (22.50 ± 8.38 HU) (p = 0.015). CONCLUSION. A markedly enhanced homogeneous central bronchial nodule or mass may suggest low-grade MEC. High-grade MEC tends to be peripheral, to have poorly defined margins, and to be lobular, heterogeneous nodules or masses with less enhancement.