A 60-year-old man was being evaluated for jaundice. CT abdomen incidentally revealed classical ‘crocodile-jaw’ morphology of the pancreatic-head (Fig. 1).

Fig. 1
figure 1

a Axial contrast enhanced CT of the abdomen at the level of the head of the pancreas reveals the duodenum being partially encased by the head of the pancreas which exhibits a crocodile-jaw appearance, b representation of crocodile-jaw appearance

Full size image

Annular pancreas is a rare congenital anomaly. It refers to a ‘trail’ of pancreatic tissue encircling either completely or incompletely the second part of duodenum [1, 2]. The exact etiopathogenesis is contentious; however, the most widely accepted theory is the early division of the ventral pancreatic anlage into two segments [1]. Complete annular pancreas presents early in life as small bowel obstruction. In contrast, most patients with incomplete or partial annular pancreas remain asymptomatic and the condition is often incidentally detected at imaging. A crocodile-jaw configuration of pancreatic head (representing extension of pancreatic tissue anterior and posterior to the duodenum) on CT or MR imaging has been reported to be highly suggestive of annular pancreas [2]. These patients have a higher incidence of concomitant pancreas divisum, chronic pancreatitis, gastric outlet obstruction, biliary obstruction and/or peptic ulceration [1, 2].