Which renal tumor is characterized by clear cells due to glycogen or lipids?

• A. Papillary carcinoma
• B. Chromophobe carcinoma
• C. Clear cell carcinoma
• D. Oncocytoma

Answer: (C)

Cells with clear cytoplasm come from high glycogen and lipid content. In histology, lipids are washed away during routine processing, and glycogen leaves pale spaces, so the tumor cells look clear under the microscope. This clear-cell appearance is the defining feature of clear cell renal cell carcinoma, the most common type of kidney cancer, which is why this option fits best.

Other renal tumors have different cellular textures: papillary carcinoma tends to form papillary structures; chromophobe carcinoma shows cells with distinct borders and pale halos but not the same clear, lipid/glycogen–rich cytoplasm; oncocytoma has eosinophilic, granular cytoplasm from many mitochondria rather than clear cells.