A 50-year-old chronic alcoholic presents to the emergency room with 12 hours of severe abdominal pain. The pain radiates to the back and is associated with an urge to vomit. Physical examination discloses exquisite abdominal tenderness. Laboratory studies show elevated serum amylase. Which of the following morphologic changes would be expected in the peripancreatic tissue of this patient?

**Core Concept**
Acute pancreatitis is a clinical condition characterized by inflammation of the pancreas, often triggered by gallstones or excessive alcohol consumption. The inflammatory process leads to morphologic changes in the peripancreatic tissue, including edema, necrosis, and hemorrhage.

**Why the Correct Answer is Right**
In acute pancreatitis, the activation of pancreatic enzymes within the pancreas leads to autodigestion of the gland and surrounding tissues. The peripancreatic tissue becomes edematous, and there may be necrosis of the pancreatic parenchyma and surrounding fat. The edema and inflammation cause the peripancreatic tissues to become fibrotic and scarred. This process is mediated by the activation of pancreatic enzymes, including trypsin, lipase, and amylase, which are normally produced in an inactive form and activated within the pancreas.

**Why Each Wrong Option is Incorrect**

* **Option A:** This option is incorrect because pancreatic pseudocysts are a complication of acute pancreatitis, but they are not a morphologic change expected in the peripancreatic tissue in the early stages of the disease.
* **Option B:** This option is incorrect because pancreatic calcifications are a feature of chronic pancreatitis, not acute pancreatitis.

**Clinical Pearl / High-Yield Fact**
The Ranson's criteria are useful for predicting the severity of acute pancreatitis. These criteria include factors such as age, white blood cell count, blood glucose level, and serum lactate dehydrogenase level.

**Correct Answer:** C.

✓ Correct Answer: C. Fat necrosis