Meckel’s diverticulum adenocarcinoma accompanied with vitelline duct remnant and huge cystic lesion: A rare case report

INTRODUCTION: Vitelline duct remnant (VDR) is a rare abnormality of the primitive yolk sac, and Meckel's diverticulum (MD) is the most common type. MD is a congenital small intestinal diverticulum that leaves the ileal side of vitelline duct, and MD adenocarcinoma is extremely rare. PRESENTATION OF CASE: A 49 year-old-man with abdominal mass was diagnosed as a huge pelvic tumor. We resected this tumor together with the invading ileum and the ileocecum. On histopathological and immunohistochemical analysis, tumor was diagnosed as adenocarcinoma and originated from the digestive tract. Considering that the cord extending from the umbilicus was connected to the tumor and that the tumor invaded the terminal ileum, we made a diagnosis of MD adenocarcinoma accompanied with the umbilical side of VDR and the huge cystic lesion bloated by tumor components filling up the duct due to cancer progression. DISCUSSION: The reported occurrence of MD tumors is 0.5%–3.2%. The incidence of adenocarcinoma is 21.7% for the malignant tumors in MD. It is likely that a highly advanced local invasion and lymph node metastases are involved and that the prognosis of this adenocarcinoma is poor. There is no recommended chemotherapeutic regimen for MD adenocarcinoma. It is expected that cases should be accumulated in the future for the development of a more optimally recommended regimen. CONCLUSION: Although the incidence of our case is extremely rare, the recognition of tumor development of the embryonic remnant origin is considered important for the treatment of this adenocarcinoma.