Hemangioblastoma and renal clear cell carcinoma distinguished by means of the AgNOR method

In view of the difficulty encountered in distinguishing between 2 degrees renal cell carcinoma (RCC) and hemangioblastoma (HBl) in the central nervous system, the AgNOR technique has been applied empirically to a series of 16 specimens of HBl, 5 primary RCC, and 6 specimens of secondary RCC in the CNS. To avoid tautology, the nature of these was confirmed by immunostaining for epithelial membrane antigen (EMA) and factor VIII-related antigen (FVII RAg). It was found that mean nuclear AgNOR counts in the stromal and endothelial cells of HBl exceeded significantly the counts in the tumor and endothelial cells of RCC, with no overlap in values. It is suggested that the AgNOR method is a useful adjunct in achieving the differential diagnosis of HBl and RCC in the nervous system.