**Core Concept**
Pseudopancreatic cysts, also known as pseudocysts, are fluid collections that develop in the setting of acute or chronic pancreatitis. They are typically characterized by a lack of an epithelial lining and are often associated with pancreatic necrosis.

**Why the Correct Answer is Right**
Pseudopancreatic cysts are indeed often associated with pancreatic necrosis and can occur in the setting of acute or chronic pancreatitis. They can also be caused by other factors such as trauma or pancreatic surgery. The fluid within the cyst is usually a combination of pancreatic juice and necrotic debris.

**Why Each Wrong Option is Incorrect**
**Option A:** This option may be incorrect if it implies that pseudopancreatic cysts are always associated with a specific type of pancreatitis, such as chronic pancreatitis. While chronic pancreatitis is a common cause, pseudocysts can also occur in the setting of acute pancreatitis.

**Option B:** This option may be incorrect if it suggests that pseudopancreatic cysts are always lined by epithelial cells. While some fluid collections may be lined by epithelium, pseudocysts are typically characterized by a lack of an epithelial lining.

**Option C:** This option may be incorrect if it implies that pseudopancreatic cysts are always caused by pancreatitis. While pancreatitis is a common cause, pseudocysts can also be caused by other factors such as trauma or pancreatic surgery.

**Option D:** This option may be incorrect if it suggests that pseudopancreatic cysts are always benign. While most pseudocysts are benign, they can become infected or rupture, leading to serious complications.

**Clinical Pearl / High-Yield Fact**
Pseudopancreatic cysts can be difficult to distinguish from true cysts, which are lined by epithelial cells. A key distinguishing feature is the presence of an epithelial lining in true cysts.

**Correct Answer: B. Pseudopancreatic cysts are not always lined by epithelial cells.**