Asymptomatic gastric adenomyoma and heterotopic pancreas in a patient with pancreatic cancer: A case report and review of the literature

BACKGROUND: Gastric adenomyoma (GA) is a rare submucosal benign neoplasm that occurs mostly in the gastric antrum and is often misdiagnosed. No standard treatment has been established for this disease in cases of malignancy. CASE SUMMARY: A 75-year-old woman with a 10-year history of hypertension was admitted to the Emergency Department of our hospital complaining of paroxysmal exacerbation of acute abdominal pain for 1 d with no apparent cause. Enhanced computed tomography and magnetic resonance imaging indicated a mass in the caudal pancreas, cholecystitis, and cholecystic polypus. Gastrointestinal endoscopy showed a mass arising from the gastric antrum. Due to the imaging findings, pancreatic cancer (PC), gastric lesion, cholecystitis, and cholecystic polypus were our primary consideration. Radical pancreatectomy, splenectomy, and cholecystectomy were performed successfully, and the gastric tumor was locally resected. Postoperative paraffin specimens confirmed the diagnosis of caudal PC, GA, and heterotopic pancreas (HP). Unfortunately, the patient died 13 mo later due to PC metastases to the liver, lung, and adrenal glands. CONCLUSION: GA is a rare benign disease, especially when occurring with HP. It may stem from the same origin as HP. This is the first case report to date of a patient suffering from the simultaneous occurrence of GA, HP, and PC. GA is a lesion that can mimic other benign or malignant gastrointestinal diseases; thus, a definitive diagnosis depends on postoperative pathological biopsy. Although GA and HP are both benign lesions, they should be resected because there is a chance of malignancy. Additional research should be conducted to better understand these submucosal lesions.