Diagnosis: Clear cell renal cell carcinoma
• It is the most common renal cell carcinoma and has the worst prognosis among the most common subtypes of renal cell carcinoma (RCC).
• Grossly it is composed of a well-defined mass with a variegated yellow appearance with hemorrhagic and necrotic foci.
• Histologically it is composed of clear polygonal cells arranged in nests or solid sheets and can be cystic or focally papillary. Clear cell RCC is graded using the Fuhrman nuclear grade system, which predicts tumor behavior. The Fuhrman nuclear grade depends on the size and irregularity of the nuclei and the presence of prominent nucleoli.
• Immunohistochemically, clear cell renal cell carcinoma is positive for epithelial membrane antigen (EMA), Pan CK, Carbonic Anhydrase 9 (CA-9), Vimentin, CD10, RCC, Pax-2, and Pax-8.
• It can arise sporadically or in association with the von Hippel-Lindau (vHL) syndrome, which involves the vHL gene on 3p25.
