Malignant GIST masquerading as a bleeding duodenal diverticulum.

fer with a diagnosis of gastrointestinal bleeding from a duodenal diverticulum. An apparent bleeding diverticulum was visualized on repeat endoscopy at the junction of the second and third part of the duodenum (l" Figure 1). Computed tomography scan revealed a large (15 ” 10 cm) heterogeneous centrally hemor− rhagic mass in the right anterior parare− nal space, abutting both the pancreas and the duodenum (l" Figure 2 a and l" Figure 2 b). At laparotomy, a 15 ” 12 ” 10 cm mass was found in the retroperito− neum immediately posterolateral to, and intimately associated with, the second part of the duodenum (l" Figure 3). The mass was dissected with a cuff of duode− nal wall, which when divided demon− strated a defect in the posterolateral wall of the duodenum, corresponding to the location of the diverticulum on endosco− py. The center of the mass had cavitated secondary to necrosis and was full of clot. This was in continuity with the lu− men of the duodenum, thus giving the appearance of a bleeding diverticulum on endoscopy (l" Figure 4). Surgical pa−