Interesting case Abdominal 35

Salient findings:

CT:

• Significant fat stranding and phlegmon surrounding the pancreas and the mildly oedematous pancreatic head, consistent with acute pancreatitis.

• No abnormal enhancement of the pancreas to suggest necrosis.

• No pancreatic duct dilation.

• Mildly distended gallbladder but no features of acute cholecystitis.

• No fluid collections, abscesses or pseudocysts.

• Mild stranding through the retroperitoneum but no ascites.

MRCP:

• No biliary duct dilation and no filling defects in the bile ducts to suggest obstructive ductal choledocholithiasis.

• Small stones lying dependently in the gallbladder lumen (no cholecystitis).

• The CBD can be seen draining into the main papilla of the duodenum at the Ampulla of Vater.

• Instead of joining the CBD at the Ampulla/major papilla to drain, the main pancreatic duct of Wirsung is seen draining separately into the minor papilla, located superior to the Ampulla of Vater – features are consistent with pancreas divisum

• The accessory pancreatic duct can be seen entering the minor papilla along with the main pancreatic duct.

• No ventral duct is seen entering the major papilla with the CBD.
  
  

Principal Diagnosis: Acute pancreatitis with underlying Pancreas divisum (type II) anomaly

Learning points:

What is the normal embryology of the pancreatic ducts?

• The formation of the pancreas and its ductal system occurs between the 4^th and 8^th weeks of gestation.

• At 4^th-5^th weeks, there are two separate pancreatic buds that form:

- The ventral bud arises from the hepatic diverticulum

- The dorsal bud arises from the dorsal part of the duodenum

• At 5-6^th weeks, the duodenum rotates and in doing so, the ventral bud moves posteriorly to lie posteroinferiorly to the dorsal bud

• At 7-8^th week, the buds then fuse.

• After fusion, the ventral bud forms the uncinate process and inferior aspect of the pancreatic head and the dorsal bud forms the superior pancreatic head, body and tail.

• Pancreas divisum results from a failure of fusion of the ventral and dorsal bugs / anlages.

What are the types of pancreas divisum?

• Type I (most common – 75%) : Main pancreatic duct drains vias the minor papilla and the CBD drains with the ventral duct through the ampulla of Vater

• Type II : Same as type 1, but with absence of the ventral duct

• Type III : Small filamentous connection between the ventral duct with the main duct prior to its drainage in to the minor papilla.

Complications:

• Acute pancreatitis

• Chronic pancreatitis

• Santoriniocele

• Diabetes

• Chronic abdominal pain

Treatment options:

• Usually conservative as is usually an incidental finding

• Pancreatic enzyme supplements

• Minor papillotomy

• Minor papilla stenting