Computed tomographyによるrenal massの診断

Abstract

During the 2 years period from 1979 to 1980, computed tomography (CT) was performed in 61 cases in which renal mass has been demonstrated by intravenous pyelography, and 33 cases were diagnosed as having renal cyst and 28 cases as renal neoplasm out of these 61 cases. Cysts showed uniform density almost corresponding to that of water, and they were round or oval in shape with sharp and smooth demarcation from the renal parenchyma. Their walls were thin and almost undetectable, and no increase in density was seen after injection of contrast media. As opposed to these, the density of neoplasms was closer to that of normal renal parenchyma and frequently inhomogeneous. They were atypical in shape with no clear cut demarcation from the renal parenchyma. Following injection of contrast media their density increased slightly. Eight out of 33 cases diagnosed as having cyst on CT underwent surgery. Renal cyst was confirmed histologically in 7 of these cases, while the remaining one case was found to have adrenal cyst. In 27 of 28 cases in which diagnosis of neoplasm was established, renal cell carcinoma was confirmed by operation. In one case infiltration of malignant pheochromocytoma into the kidney was confirmed. CT could differentiate cyst from neoplasm with 100% accuracy and in none of the cases cyst was misdiagnosed as neoplasm or vice versa. However, since there is a possibility that cyst or neoplasm arisen from the adrenal or retroperitoneal cavity may be misdiagnosed as originated from the kidney, cautions should be taken in interpretation of CT.