Hyperplasia of Brunner's glands is considered an uncommon finding; its wide range of morphological variation has led to confusing identifying terminology which includes: hyperplasia, adenoma, and hamartoma. Some investigators have suggested that hyperplasia of Brunner's glands is hamartomatous in nature, whereas others have favored a causative relationship that results from gastric acid hypersecretion. Although most commonly an incidental finding, that appears as multiple small submucosal sessile nodules, usually located in the duodenal bulb, it can lead to clinically significant symptoms including gastrointestinal bleeding, abdominal pain, and intestinal obstruction. Here, we report a case of hyperplasia of multiple cystic Brunner's glands on the duodenal bulb in a patient with acute pancreatitis; they were discovered incidentally on abdominal CT and duodenoscopy. This is the first report of hyperplasia of Brunner's glands with these morphological characteristics.