CT findings in benign fibrous mesothelioma of the pleura: pathologic correlation in nine patients.

The CT findings in cases of benign fibrous mesothelioma of the pleura have been described previously, but little attention has been given to a correlation of these findings with the pathologic appearance of the tumors. Accordingly, we analyzed the CT scans in nine proved cases in which pathologic studies were available and compared the pathologic findings with the CT appearance of the tumors. On enhanced CT scans (available in eight patients), the lesions showed significant enhancement in all cases. Pathologic examination showed that the enhancement could be explained by the vascularity of the tumor. Areas of myxoid (n = 7) or cystic (n = 3) degeneration and hemorrhage (n = 3) seen in the pathologic specimens correlated with round or tubular low-attenuation areas on unenhanced and enhanced CT scans. On unenhanced CT scans (n = 3), the tumor density was the same as that of the surrounding musculature. Calcification was seen in one patient. Large lesions showed lobulated borders, but no invasion into the lung parenchyma and chest wall was noted. There was no pleural effusion. Our experience suggests that intense enhancement of the tumors occurs because of the vascularity of the tumors. Areas of low attenuation in the tumors on CT were due to foci of myxoid or cystic degeneration and hemorrhage in the lesion.