Hepatoid adenocarcinoma arising from heterotopic pancreas of the ileum: A case report

INTRODUCTION: Hepatoid adenocarcinoma (HAC) is a rare neoplasm with a striking morphologic similarity to hepatocellular carcinoma. The most common sites of HAC are the stomach, lung, and pancreas. CASE REPORT: Here we report a rare case of HAC arising from the heterotopic pancreas (Heinrich type II) in the ileum with lymph node metastasis. A 56-year-old man was admitted to our hospital presenting with bloody stools under no obvious predisposing causes. The colonoscopy and the gastroscopy showed no pathological findings. A computed tomography scan showed an intussusception of ileum. Then partial resection of ileum was performed with end-to-end anastomosis and appendectomy. Histopathological examination showed a malignant transformation of heterotopic pancreas (Heinrich type II) in the ileum. We made the diagnosis of HAC based on clinical pathological features and immunochemical staining. The patient received chemotherapy and died 9 months later. CONCLUSION: To our best knowledge, this is the first reported case of HAC originated from a heterotopic pancreas in the ileum. The clinical pathological features and immunochemical staining are important for correct diagnosis of HAC.