This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
'Double duct' sign is diagnostic of 
Select and explain. 
A. Periampullary carcinoma, B. Gallbladder carcinoma, C. Klatskin's carcinoma, D. Hepatocellular carcinoma
A: Periampullary carcinoma
Answer: A: Periampullary carcinoma 
Explanation: In pancreatic carcinoma(periampullary carcinoma) , the main pancreatic duct may be narrowed or completely obstructed at the site of the tumour, or the distal bile duct may be narrowed. Concurrent narrowing of both ducts results in the so called double duct signReference : page 1134 Bailey and Love's sho practice of surgery 25th edition