Thoracic neurilemomas: an analysis of computed tomography findings in 36 patients

On computed tomography (CT), neurilemomas have generically been described as well-defined, round masses with heterogeneous contrast enhancement. The CT scans of 38 surgically proven thoracic neurilemomas in 36 patients were reviewed to characterize further the CT features of this tumor, with an emphasis on different enhancement patterns. Unenhanced CT was available in 32 patients; 10 tumors appeared isodense, and 22 tumors appeared slightly hypodense compared with chest wall muscle. Except for an intraosseous neurilemoma of the T8 vertebral body, which mimicked bone metastasis, the tumors could be categorized into five different patterns on CT after contrast enhancement. Twenty tumors (54.1%) revealed diffuse, but amorphous and inhomogeneous enhancement. Seventeen (45.9%) tumors appeared as masses with multiple hypodense or cystic areas. Of these 17, the pattern was somewhat radial enhancement (n = 6, 16.2%), peripheral enhancement with a large central hypodense area (n = 5, 13.5%), homogeneous hypodensity (n = 5, 13.5%), and central enhancement with peripheral hypodensity (n = l, 2.7%). Appreciation of various CT manifestations is important in the diagnosis of this tumor.