A 55 year old male presents with features of Obstructive Jaundice. He also reports a weight loss of seven kilograms in last two months. On CT scan, the CBD is dilated till the lower end and the main pancreatic duct is also dialated. Pancreas is normal.The most likely diagnosis is –

**Core Concept**
Obstructive jaundice, characterized by a conjugated hyperbilirubinemia, is often due to an obstruction in the bile ducts. The presence of a dilated common bile duct (CBD) and main pancreatic duct (MPD) on imaging studies is suggestive of a pancreaticobiliary malignancy.

**Why the Correct Answer is Right**
The patient's symptoms, including weight loss and obstructive jaundice, are classic for a pancreatic cancer. The dilated CBD and MPD are a result of the tumor's growth, which is obstructing the flow of bile and pancreatic secretions. The pancreas itself appears normal, which suggests that the tumor is likely located in the head of the pancreas, causing the obstruction.

**Why Each Wrong Option is Incorrect**
**Option A:** This option might be tempting, but it is incorrect because the pancreas is normal, making a pancreatic pseudocyst or abscess less likely.
**Option B:** This option is incorrect because the patient's symptoms and imaging findings do not suggest a gallstone disease, which would more likely cause a dilated CBD with a normal MPD.
**Option C:** This option is incorrect because a choledocholithiasis would more likely cause a dilated CBD with a normal MPD, and the patient's symptoms and weight loss are not typical for a gallstone.

**Clinical Pearl / High-Yield Fact**
A dilated CBD and MPD on imaging studies, in the presence of obstructive jaundice and weight loss, is highly suggestive of a pancreatic cancer, particularly in the head of the pancreas.

**Correct Answer:** C.

✓ Correct Answer: D. Periampullary Carcinoma