**Core Concept**
A pseudocyst of the pancreas is a fluid collection that arises from the pancreas, typically as a result of pancreatitis. It is characterized by a wall of fibrous or granulation tissue surrounding a collection of pancreatic juices, but lacks an epithelial lining, distinguishing it from a true cyst.

**Why the Correct Answer is Right**
Pseudocysts of the pancreas can become large and may extend beyond the limits of the pancreas, potentially reaching distant locations in the abdominal cavity. This is due to the fluid accumulation and the gradual expansion of the cyst. As a result, pseudocysts can present in various locations, from the mediastinum to the pubis, depending on their size and location of formation. The mediastinum is the central part of the chest cavity, and the pubis is the front of the pelvis. This wide range of possible presentation locations is a key characteristic of pancreatic pseudocysts.

**Why Each Wrong Option is Incorrect**
**Option A:** A pseudocyst is not a true cyst because it lacks an epithelial lining, which is a critical feature that distinguishes true cysts from pseudocysts.
**Option B:** While penetrating trauma can cause pancreatitis and potentially lead to the formation of a pseudocyst, it is not the most common cause of pseudocyst formation. The most common cause is pancreatitis due to gallstones or alcohol abuse.
**Option C:** The treatment of a pancreatic pseudocyst depends on its size, location, and symptoms. While cystogastrostomy (creating a connection between the cyst and the stomach) may be an option for certain large pseudocysts, it is not a universally applicable treatment for pseudocysts greater than 2 cm in size.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that pancreatic pseudocysts can be asymptomatic for a long time and may present with a wide range of symptoms, including abdominal pain, weight loss, and even jaundice. A high index of suspicion is necessary for early diagnosis and treatment.

**✓ Correct Answer: D. Can present from mediastinum to pubis**