ABSTRACT
PURPOSE: To assess the usefulness of CT scanning in the differentiation of stage T3a from T2 in renal cell carcinoma. MATERIALS AND METHODS: Among patients with pathologically proven renal cell carcinoma, 114 at stages T2 and T3a were divided into three groups, as follows: intact capsule (T2) n=40, capsular involvement (T2) n=38, and capsular penetration (T3a) n=36. By referring to contrast-enhanced CT scans, we retrospectively compared the groups in terms of tumor margin, the frequency with which a tumor bulged more than 3 cm beyond the renal contour, the presence or absence of peritumoral collateral vessels, thickening of Gerota 's fascia, and perinephric strands. RESULTS: An irregular margin was more common in the capsular penetration group than in the other two groups (p0.05). CONCLUSION: In determining the tumor stage of renal cell carcinoma, CT is not helpful in differentiating between a tumor with capsular penetration (T3a) and one with capsular invasion (T2), though differentiation of the T3a stage from the T2 stage, without capsular invasion, is reliable. When a tumor has an irregular margin, however, the possibility that it is at stage T3a should be considered.