Spontaneous regression of gastric gastrinoma after resection of metastases to the lesser omentum: A case report and review of literature

BACKGROUND Gastric gastrinoma and spontaneous tumor regression are both very rarely encountered. We report the first case of spontaneous regression of gastric gastrinoma. CASE SUMMARY A 37-year-old man with a 9-year history of chronic abdominal pain was referred for evaluation of an 8 cm mass in the lesser omentum discovered incidentally on abdominal computed tomography. The tumor was diagnosed as grade 2 neuroendocrine neoplasm (NEN) on endoscopic ultrasound-guided fine-needle aspiration. Screening esophagogastroduodenoscopy revealed a 7 mm red polypoid lesion with central depression in the gastric antrum, also confirmed to be a grade 2 NEN. Laparoscopic removal of the abdominal mass confirmed it to be a metastatic gastrinoma lesion. The gastric lesion was subsequently diagnosed as primary gastric gastrinoma. Three months later, the gastric lesion had disappeared without treatment. The patient remains symptom-free with normal fasting serum gastrin and no recurrence of gastrinoma during 36 mo of follow-up. CONCLUSION Gastric gastrinoma may arise as a polypoid lesion in the gastric antrum. Spontaneous regression can rarely occur after biopsy.