Donor kidneys with miliary papillary renal cell neoplasia: the role of the pathologist in determining suitability for transplantation

BACKGROUND: Kidneys with single or multiple tumors, provided that they have histological features recognized as being associated with low risk of recurrence, are considered suitable for transplantation. It is known that kidneys with multiple primary renal tumors show poor renal function and that function dramatically declines when tumors have a miliary configuration. Despite this, no guidelines are in place to differentiate between multifocal tumors and those that are miliary in nature. CASE REPORT: We report a case in which initial examination revealed papillary renal cell neoplasia in deceased donor kidneys, which were later confirmed on histological and genetic testing to be multiple and miliary in distribution. Gross examination showed closely opposed neoplasms, and on histological examination these were found to be papillary renal cell carcinomas and renal papillary adenomas. This ultimately led to the decision that both kidneys were unsuitable for transplantation. CONCLUSIONS: At present there are no recommendations as to how tumor-bearing donor kidneys should be handled in order to determine if miliary neoplasia is present. From our case it is apparent that, in addition to obvious tumor nodules, at least 3 samples of cortex should be examined. This case highlights the important role of the pathologist in assessing donor kidneys with evidence of neoplasia.