Despite the chromosomal numerical abnormalities typical of RO, we classified these tumors as part of the spectrum of PRCC because of their predominant papillary/tubulopapillary architecture, immunoprofile that included reactivity for AMACR, vimentin and lack of reactivity for CD117, all of which is incompatible with the diagnosis of RO.
The remaining 2 carcinomas previously reported as malignant RO owing to cytological atypia and lymph node metastasis showed immunoprofile of RCC(-)/CD117(+) and absence of numeric changes for chromosomes 7, 17, and Y or loss of loci 3p25 or 3p14.
Our results demonstrate that KIT could be a useful immunophenotypic marker for chromophobe RCC and renal oncocytoma; therefore, it has value for the precise classification of renal cortical epithelial tumors.