Anatomic/radiologic classification of renal cortical nodules.

Abstract

A cortical nodule is defined as a focus of more normal renal cortical tissue than usual in an otherwise normal kidney. Such nodules can mimic renal tumors on excretory urography. The urographic features of 29 cases of renal cortical nodules were correlated with arteriographic features to determine if a pattern of different anatomic types could be discerned. The cortical nodules fell into three anatomic groups (similar to Hodson's dissection classification): (1) subcapsular, (2) hilar lip, and (3) septa of Bertin. These anatomic groupings are proposed as a classification scheme for radiologic use. Using this classification, it was found that cortical nodules have urographic features that permit distinction of one type of cortical nodule from another. A better understanding of cortical nodules, based on this classification, should result in more certain urographic diagnosis of cortical nodule. Similarly, mistaking a cortical nodule for renal tumor on urography should be less likely to occur.