Unusual Presentation of a Gastrointestinal Stromal Tumor in a Small Intestine Diverticulum.

A 50-year-old female with no significant medical history initially presented to an urgent care center with symptoms of acute onset abdominal pain, nausea, and emesis. Chest and abdominal X-ray revealed free air under the diaphragm, prompting immediate transfer to the emergency department. Continued abdominal tenderness and pain were concerning for perforated viscus. The patient was transferred to the operating room, and diagnostic laparoscopy was performed. Inflammation and contamination were discovered in the right side of the abdomen and pelvis secondary to a small bowel (SB) perforation. Segmental SB resection revealed a perforated diverticulum. Pathological examination confirmed a diagnosis of gastrointestinal stromal tumor (GIST) at the perforated segment. On postoperative day 5, the patient was discharged home, and at 30-month follow-up, the patient continued to do well. Although rare, SB diverticula are commonly false (i.e., pseudodiverticula). The concomitant presence of a GIST in a true SB diverticulum presenting with perforation has not yet been reported.