This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urogenital System, Subject name: Radiology
Spider leg sign on IVP suggests: 
Select and explain. 
A. Renal stone, B. Polycystic kidney, C. Hypernephroma, D. Hydronephrosis
B: Polycystic kidney
Answer: B: Polycystic kidney 
Explanation: Ans. (b) Polycystic kidneyRef: Radiological and imaging secrets 2nd ed. / 79* Polycystic kidney autosomal dominant and recessive forms multiple cysts that deform the pelvi-calyceal system resulting in spider leg sign.* MC extra -renal malformation in polycystic kidney disease = hepatic cysts* MC Cardiac malformation in polycystic kidney disease = mitral valve prolapse* MC GIT malformation in polycystic kidney disease= colonic diverticulosisAlso KnowREMEMBER THESE IMPORTANT RADIOLOGICAL SIGNS IN UROLOGY* Spider leg appearance--polycystic kidney* Cobra head appearance--ureterocele* Flower vase appearance of ureters--horse shoe kidney* Sandy patches--schistosomiasis of bladder* Soap bubble appearance---hydronephrosis