Renal adenoma. Clinicopathological and histochemical studies

We report the results of clinicopathological and histochemical studies on 64 renal adenomas found in 22 patients. We selected typical renal adenomas for these studies, discarding borderline lesions. The ages of the patients ranged from 42 to 84 years, with an average of 61 years. Male to female sex ratio was 6.3:1. The background conditions included renal cell carcinoma, long-term dialysis, chronic glomerulonephritis, pyelonephritis, hydronephrosis and polycystic kidney. The sizes of the tumors ranged from 0.1 to 2.3 mm in maximum diameter, with an average of 0.9 mm. All the tumors were located in the cortex, especially in the superficial one-third. The cytoplasm of the tumor cells was predominantly eosinophilic, and the tumor structure was predominantly papillary. Histochemical study of 19 adenomas from 13 patients demonstrated that all of the adenomas from 13 patients demonstrated that all of the adenomas were positive for EMA, and for at least one marker of the distal tubulus, i.e., DBA, PNA, SBA and PKK1, and that 9 adenomas were positive for at least one marker of the proximal tubulus, i.e., LM1 and LTA. Renal adenomas had predominant histochemical features of the distal tubulus, suggesting differentiation to a distal tubulus-like histology.