This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney and ureter, Subject name: Surgery
The typical appearance of "spider leg" on excretory urography is seen in: 
Select and explain. 
A. Hydronephrosis, B. Polycystic kidney, C. Medullary sponge kidney, D. Renal cell carcinoma
B: Polycystic kidney
Answer: B: Polycystic kidney 
Explanation: Diagnosis USG: Enlarged kidney with uniformly medullary echogenicity. IVP in ADPKD Stretching of the calyces by the cysts (spider leg or ball like deformity. Bubble appearance (calyceal distoion) Swiss cheese appearance. CT scan is IOC in ADPKD