Beak-Like Extension of the Pancreatic Uncinate Process on MDCT

Objective We aimed to evaluate the pancreatic uncinate process with a beak-like extension (BLE) beyond the left border of the superior mesenteric artery, to define the cause of BLE, and to differentiate BLE from hyperplasia. Methods We retrospectively reviewed 1042 triple-phase contrast-enhanced multidetector-row computed tomography (3P-CE-MDCT) examinations of 500 patients. Finally, 38 patients (28 men, 10 women; mean age, 66 years) with 140 3P-CE-MDCT images showing BLE were studied regarding BLE size, contour, and cause. The superior mesenteric artery position was also evaluated. Results Beak-like extensions were found in 7.6% of patients. Most were caused by movement of the small bowel mesentery (n = 21, 55%), with deviation of mesenteric vessels or mass effect from expanded adjacent organs (n = 3, 8%). Seven patients (18.5%) had true hyperplasia. Conclusions Beak-like extension is caused by movement of the small bowel mesentery with deviation of mesenteric vessels or by adjacent organ expansion. Beak-like extension closely mimics other pathology on nonenhanced MDCT.