A rare case of gastric cancer associated with gastric diverticulum.

RATIONALE: Gastric cancer associated with prepyloric diverticulum is the most uncommon form of gastric cancer. It may be very challenging to diagnose as the lesion located among gastric antrum, pancreas, and transverse colon. We here reported a rare case of gastric cancer associated with gastric diverticulum involved part of transverse colon and head of pancreas.

PATIENT CONCERNS: Abdominal pain and vomiting for 5 days.

DIAGNOSES: First diagnosis: colon cancer. Final diagnosis: gastric cancer from gastric diverticulum.

INTERVENTIONS: Three cycles of chemotherapy and operation.

OUTCOMES: Regular follow-up 1 month after operation showed satisfactory recovery with no tumor recurrence.

LESSONS: This case underscores the importance of considering malignancy in atypical diverticular lesions.