[1393] Retractile Pancreatoduodenopathy with Neural Hypertrophy

PA Bejarano, MT Garcia, LP Herrera. University of Miami School of Medicine/Jackson Memorial Hospital, Miami, FL

Background: Most Whipple procedures are performed to treat a malignant process. However, a fraction of them reveal benign non-neoplastic conditions. One such case is the so-called paraduodenal pancreatitis characterized by chronic inflammation, myofibroblastic proliferation, dilated ducts, and cysts. It is associated with heavy alcohol intake. In this study we identified an unusual histopathological process involving the wall of the duodenum and the head of the pancreas that appears to be different from what is known as paraduodenal pancreatitis.
Design: The histological slides of 420 consecutive Whipple procedure specimens were reviewed. Of these, 35 showed benign non-neoplastic conditions, and among these, four were selected because of their unique features.
Results: There were two women and two men who ranged in age from 41 to 71 years (mean: 56 y). Imaging studies showed a duodenal mass with pancreatic involvement. Gross examination of the specimens revealed irregular areas of white-tan fibrosis measuring 2.0 cm (range 1.5 to 2.5 cm) and involving the duodenal wall. Microscopically, the most remarkable feature was the presence of sub-duodenal and periductal thickened trunks of peripheral nerves dissecting and crossing the connective tissue and the pancreatic acini. These individual neural structures had a diameter of up to 1.7 mm and in areas they formed aggregates of up to 2.3 mm. They ran in a radial and centrifugal fashion from the duodenum into the pancreas. The arteries and arterioles in the area were markedly thickened, showing fibrointimal proliferation. In one case, recanalized thrombi were present. The interface between the duodenum and the pancreas was effaced by fibrosis with pancreatic tissue pulled into the overlying duodenal muscularis mucosa. No inflammation of the pancreas was present in 3 of the cases. Inflammation around the bile duct found in the fourth case was associated with the presence of a duct catheter. There was no necrosis, myofibroblastic proliferation, cysts, calculi, eosinophils, or Brunner's gland hyperplasia.
Conclusions: The structural anomaly of nerve hypertrophy, fibrosis, thickened blood vessels, minimal to absent inflammation, and retraction of the pancreas into the duodenum all resulting in the formation of mass is found in 0.1% of all pancreatoduodenectomies. While it may correspond to a variant of paraduodenal pancreatitis, a hamartomatous process or an acquired phenomenon related to ischemia may be considered. It enters in the differential diagnosis of causes of duodenal/pancreatic masses.
Category: Liver & Pancreas

Wednesday, March 11, 2009 9:30 AM

Poster Session V # 226, Wednesday Morning