Duodenal diverticula are relatively common, but perforations are rare and therapy has not yet been standardized. The most common location of diverticula is the descending duodenum, usually on the lateral side next to the pancreas, so perforations present with an atypical clinical course. We present a case of a 73year-old female patient with epigastric pain and nausea. Abdominal CT revealed an air-fluid collection near the laterocaudal border of the descending duodenum, suggestive of duodenal microperforation and incipient abscess formation. During the operation, a diverticulectomy was performed with primary duodenal closure and abdominal drainage. A diverticulum microperforation contains some extraduodenal air bubbles, no evidence of abscess, and free air in the subdiaphragmatic region. It is an imaging entity with distinct clinical and biochemical features, and radiological findings often determine the final decision on treatment.