Paraduodenal pancreatitis

Clinical History

A 44-year-old chronic male alcoholic presented with a long standing history of recurrent epsiodes of upper abdominal pain and gradual weight loss. Laboratory examination revealed mildly elevated s.bilirubin (1.8 mg/dl) and markedly elevated serum alkaline phosphatase. Serum amylase and lipase and CEA and CA19.9 were within the normal range.

Imaging Findings

Non-contrast MRI of the abdomen and MRCP revealed an atrophic pancreas with dilated main pancreatic duct (MPD) and its side branches. A smooth distal CBD stricture was also seen with upstream mild biliary dilatation. Also present were multiple small smooth-walled cystic foci along the pancreatic head, pancreatico-duodenal groove and the medial duodenal wall. Findings were consistent with para-duodenal pancreatitis.

Discussion

Paraduodenal pancreatitis (PP) is a distinct clinicopatholgical entity recently described by Adsay and Zamboni in 2004 [1]. Paraduodenal pancreatitis refers to a distinct form of chronic pancreatitis occurring predominantly in and around the duodenal wall (near the minor papilla). This is an umbrella-term used for various conditions which previously had a variety of names, including cystic dystrophy of heterotopic pancreas, para-duodenal wall cyst, pancreatic hamartoma of duodenum, myoadenomatosis, and groove pancreatitis [1-5]. Adsay and Zamboni demonstrated that all of these conditions exhibited common histopathological findings of chronic inflammatory, cystic, and fibrotic changes in the duodenal wall and the adjacent pancreatic tissue near the minor papilla [1-2]. Common histological findings include thickened duodenal wall containing dilated ducts and pseudocystic changes, Brunner's gland hyperplasia, dense myxoid stromal proliferation with intervening rounded lobules of pancreatic acinar-tissue, spillover of fibrosis into the adjacent pancreas and marked scarring with ill-defined borders mimicking pancreatic tumours. A disturbance of the flow of pancreatic juice through the Santorini duct and presence of heterotopic pancreatic tissue within the duodenal wall have been implicated as important contributory factors for the development of paraduodenal pancreatitis.

Paraduodenal pancreatitis is predominantly seen in male patients, 40-50 years of age, with a history of chronic alcohol abuse and/or smoking [1, 2]. These patients usually seek medical attention for complains pertaining to chronic pancreatitis. Progressive scarring, fibrosis and luminal compromise of the duodenum can manifest as gastric outlet obstruction. Inflammatory stricture or compression of distal common bile duct can present with jaundice.

Endoscopic ultrasongraphy (EUS) is the considered the preferred modality amongst various other options available including MRI and MRCP. Paraduodenal pancreatitis manifests as either cystic lesions (cystic variant) or a solid-mass occurring predominantly in and around the minor papilla (solid variant) [2]. Cystic variant is characterised by the presence of cysts in the duodenal wall and cysts within the pancreatico-duodenal groove (paraduodenal cysts) with or without inflammation, thickening and fibrosis of the duodenum. In contrast, the solid variant is characterised by the presence of a sheet-like mass corresponding to the fibrous-scar predominantly located in the pancreaticoduodenal groove (pure form); which may also sometimes extend medially to involve the pancreatic head and the main pancreatic duct (segmental form of groove pancreatitis).

Surgical resection in the form of pancreatico-duodenectomy is considered to be the preferred therapeutic option in symptomatic cases of paraduodenal pancreatitis [2].

Differential Diagnosis List

Final Diagnosis

Paraduodenal pancreatitis

URL:	https://www.eurorad.org/case/9436
DOI:	10.1594/EURORAD/CASE.9436
ISSN:	1563-4086