Fig. 5

Oncocytic renal tumors and some of their differential diagnoses. Oncocytoma – typical area of insular growth of oncocytic cells in a loose fibrous stroma (a HE, 100x). Succinate dehydrogenase (SDH) deficient renal cell carcinoma shows diffuse solid growth of eosinophilic cells with and vacuolated cytoplasm or granular flocculent appearance (b HE, 200x; courtesy of Dr. Kiril Trpkov, University of Calgary). Tubulocystic carcinoma is formed by small and medium sized tubules with occasional cystic dilated tubules. The tumor cells have eosinophilic/oncocytic cytoplasm and nuclei show a typical prominent nucleolus (HE: c 10x and d 100x). Acquired cystic disease associated renal cell carcinoma typically displays sieve-like morphology and microcystic architecture with oxalate crystals (e HE, 100x). Epithelioid angiomyolipoma may mimic epithelial tumors with clear and eosinophilic cells (f HE, 100x)