Renal Oncocytoma With Perinephric Fat Invasion.
Williamson SR. Renal oncocytoma with perinephric fat invasion. Int J Surg Pathol 2016.
International journal of surgical pathology
Since its initial recognition,1 oncocytoma is now widely recognized and accepted as a benign renal neoplasm.2-4 With the exception of exceedingly rare putative examples of metastasis,5 these tumors are considered to have no significant potential for disease progression. Interestingly, several studies have shown that although oncocytoma cells may intermingle with perinephric fat,2-4 a finding that would qualify for high-stage (pT3a) disease in renal cell carcinoma, this does not alter the benign clinical course of this tumor. Similarly, rare examples of oncocytoma invading the renal vein or vein branches have also been described,6 without an apparent adverse effect on outcome. The nature and significance of these phenomena are poorly understood; however, notably oncocytomas and chromophobe renal cell carcinomas often have an incomplete or absent peritumoral pseudocapsule,7 in contrast to clear cell and papillary renal cell carcinomas, suggesting that the biologic differences between these renal tumor types also impart differences in pattern of growth. This report demonstrates an illustrative example of oncocytoma intermingling with the perinephric fat, which was suspected at the time of gross examination (Figure 1A and B) and confirmed microscopically (Figure 2A-D).
Medical Subject Headings
Adenoma, Oxyphilic; Adipose Tissue; Humans; Kidney Neoplasms; Neoplasm Invasiveness