Endoscopic ultrasonography of duodenal aberrant pancreas: comparison with histology after endoscopic resection.

We present the case of a 45-year-old man with an aberrant pancreas in the duodenum. He was referred to our hospital for gastric cancer screening. On upper gastrointestinal endoscopy, a submucosal tumor was noted in the second portion of the duodenum; it was 10 mm in diameter, with a smooth surface and bridging fold. Endoscopic ultrasonography (EUS) showed a hypoechoic lesion with small anechoic areas located in the third sonographic layer of the duodenum wall. To confirm the exact diagnosis, endoscopic resection was performed. The histological diagnosis was aberrant pancreas, Heinrich type II. The hypoechoic lesion and anechoic areas on EUS findings clearly corresponded with pancreatic acinus cells and duct dilation on histological findings, respectively. EUS findings are useful to diagnosis a duodenal aberrant pancreas that has ductal structures.