Fine needle aspiration of chromophobe renal cell carcinoma

To report the fine needle aspiration (FNA) features of both a typical and an eosinophilic variant of chromophobe renal cell carcinoma.

The files of Brigham & Women's Hospital were searched for renal FNAs of chromophobe renal cell carcinoma with surgical follow-up.

Both tumors had single cells and small groups of cells with frequent binucleation, nuclear hyperchromasia, nuclear outline irregularity, significant nuclear size variation, abundant cytoplasm and a thickened cytoplasmic membrane. Hale's colloidal iron was strongly positive in a diffuse cytoplasmic pattern. The typical variant resembled clear cell renal cell carcinoma; differentiation was best accomplished by noting the predominance of single cells rather than large groups, binucleation, nuclear atypia and thickened cytoplasmic membranes. The eosinophilic variant resembled oncocytoma. Differentiation was best accomplished by noting the nuclear atypia and lack of uniform granularity of the cytoplasm.

Chromophobe renal cell carcinoma has distinctive cytologic features on FNA; Hale's colloidal iron can be helpful in difficult cases.