Журнал клинической и экспериментальной патологии

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Renal Oncocytoma and Cromophobe Renal Cell Carcinoma: Main Morphological Differences and Proposal of a Simple Histochemical and Immunohistochemical Panel to separate them

Gallegos Ivan, Carrasco Gonzalo, Fernandez Cristina, Castillo Octavio and Valdevenito Raul

Introduction: Renal Oncocytoma (RO) and Chromophobe Renal Cell Carcinoma (ChCCR) are within spectrum of “eosinophilic renal neoplasms” that can share morphological features. In some instances, it can be challenging differentiate both entities based only on the HE. For this reason, complementary ancillary techniques are needed.

Methodology: Sixteen RO cases and 21 ChCCR cases were evaluated for macroscopic and microscopic features, defining their architectural, nuclear and special stains criterion. Hale`s Coloidal Iron (HCI), Citokeratin 7 and CD15 were performed.

Results: Significant (p<.001) morphological differences were the pattern of grown (16/16 RO nested type vs 19/21 ChCCR diffuse type), nuclear morphology (“raisinoid” nuclei: 0/16 RO vs. 19/21 ChRCC) and presence of mitotic figure (0/16 RO vs. 16/21 ChCCR). Special stains showed that HCI was positive in 2/16 cases of RO and 20/21 of ChCCR, CK7 was positive in 1/16 cases of RO and 18/21 of ChCCR and CD15 was positive in 13/16 RO and 4/21 of ChCCR (p<.001).

Conclusion: Main differences beetwen RO and ChCCR are respectively the pattern of grown (nested/diffuse), raisinoid nucleus (-/+), and presence of mitosis (-/+). Besides ancillary techniques show HCH (-/+), CK7 (-/+) and CD15 (+/-). The ancillary panel of stains is very easy to perform and useful to achieve the correct diagnosis.