ABSTRACT

Adenoma The most common neoplasm of renal tubular epithelium are papillary adenoma.

These lesions are usually discovered during autopsy with a frequency between 7 and 22%. They are located in the renal cortex and are typically <1 cm in size. Histochemical studies suggest they originate from distal tubular epithelium. Micro­ scopic morphology of these lesions resembles low-grade papillary renal cell carcinoma and no reliable cytologic criteria can distinguish between the two. With the diffi­ culty in differentiating these lesions histologically, it is even more problematic to make the diagnosis of these lesions clinically. Previously, it was thought that lesions smaller than 3 cm had a low propensity for metastasis. However, several reports have shown that size does not accurately predict metastatic potential. Thus, it would be prudent to treat solid lesions of renal parenchyma as malignant lesions pending histopathologic analysis.