A patient with duodenal diverticulitis who was initially misdiagnosed with stromal tumor of the duodenum is presented. This case is of interest because it illustrates difficulties in the interpretation of auxiliary investigations and the choice of the best treatment option. US and CT images revealed two large ovoid masses of fluid density in the duodenal wall which may have suggested stromal tumor of the duodenum as well as periampullary cystic neoplasm, the more so because intramural tumor of the duodenum was seen in duodenoscopy. A similar picture may also be seen in duodenal diverticula, especially in diverticula which are not filled with gas or a combination of fluid and gas. This case demonstrates one such entity.