Aggressive surgical resection in locally advanced hepatopancreatobiliary (HPB) malignancies is frequently advocated as the only potentially curative treatment. In recent years, advances in chemotherapy regimens and surgical techniques have led to improved oncologic outcomes and overall survival, by increasing the rates of radical (R0) resections. Vascular resections are increasingly reported to further increase disease clearance rates. Within this perspective, the issue of vascular reconstruction has raised growing interest, drawing particular attention to vascular substitutes and surgical techniques for reconstruction. A case of extrahepatic cholangiocarcinoma with high clinical suspicion of vascular infiltration of the portal trunk at preoperative assessment is reported. An autologous interposition graft, harvested from diaphragmatic peritoneum, was chosen as a vascular substitute leading to successful portal trunk reconstruction and overcoming all possible drawbacks associated with cadaveric and artificial grafts reconstructions. This solution was strategic to ensure complete oncologic clearance averting the risk of positive margins (R1) at final pathology.