Which renal tumor is most common in adults?

• A. Wilms tumor
• B. Transitional cell carcinoma
• C. Renal cell carcinoma
• D. Medullary carcinoma

Answer: (C)

The main idea here is that renal cell carcinoma is the most common malignant kidney tumor in adults. It develops from the kidney’s cortical parenchyma (the renal tubule–origin cells) and accounts for the majority of adult kidney cancers. Wilms tumor, by contrast, is the classic kidney cancer of children (nephroblastoma), not adults. Transitional cell carcinoma arises from the urothelium lining the renal pelvis and ureter, and while it occurs in adults, it’s not as common as renal cell carcinoma when we’re talking about tumors inside the kidney itself. Medullary carcinoma is a rare type that typically appears in younger patients, especially with sickle cell trait. So, in adults, the most frequent renal tumor is renal cell carcinoma.