|ECR 2013 / C-2131|
|Lesions of the pancreaticoduodenal groove, a pictorial review|
Imaging findings OR Procedure details
Diseases of the PD groove can be classified by their origin, relating to the surrounding structures. Disease processes of the pancreas, duodenum, lymph nodes, common bile duct and disease processes extending into the groove from elsewhere.
Acute pancreatitis, Fig. 3
Acute pancreatitis involving the PD groove is different from groove pancreatitis. It is characterised by inflammatory change and fluid in the PD groove that changes over time. The remainder of the pancreas is normal in appearance.
Groove pancreatitis is a form of chronic segmental pancreatitis affecting the groove in the region of the pancreatic head, duodenum, and common bile duct. The aetiology remains unclear, but it may relate to peptic ulcers, duodenal wall cysts and gastric resection. A soft tissue mass is noticed in the PD groove which has been shown to consist of fibrous scar. There is late enhancement of this scar on imaging. Cystic dystrophy of the duodenal wall is associated, with thickening of the wall of the duodenum and cysts within it.
Pancreatic adenocarcinoma can occasionally present as an exophytic lesion extending into the PD groove. The mass is inseparable from the pancreatic head, may cause biliary duct dilatation and there may be adjacent vascular invasion.
Neuro-endocrine tumour Fig. 10
This tumour can also present as a hyperenhancing mass in the PD groove. Features that can aid diagnosis are the hyperenhancement of the lesion as well as the presence of hypervascular liver metastases.
A diverticulum of the second or third part of the duodenum can present as a mass in the PD groove. It is important to distinguish as it may mimic lesions such as a pseudocyst or abscess. A diverticulum could also become impacted and present as duodenal diverticulitis.
Lymph nodes in the PD groove drain the liver, biliary tract, duodenum and pancreas. Enlarged nodes in this location may represent infection, lymphoma or metastases.
Enlarged nodes elsewhere can be a clue to the diagnosis of lymphoma. An enlarged node can sometimes be difficult to distinguish from a primary lesion of the pancreas.
4. Common Bile Duct
A cholangiocarcinoma extending into the PD groove should have associated intra- and extra-hepatic biliary duct dilatation terminating at the level of the lesion.
This may mimic fluid in the PD groove. MRCP can help to establish a communication between the lesion in the PD groove and the common bile duct.
5. Invasion from elsewhere
In theory, adjacent disease processes may invade the PD groove. Fig. 18-20 show a benign retroperitoneal haemangioma, which involves the PD groove. It is characterised by water signal fluid and is soft, being easily indented by its surrounding structures.
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ECR 2013 / C-2649
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