Objective To reveal the significance of D2-40/CK19 dual immunohistochemistry for micrometastasis of peripancreatic neural plexus in patients with pancreatic cancer. Methods Between January 2006 and January 2007, 44 patients with pancreatic duct adenocarcinoma underwent extended radical resection. Conventional hematoxylin/eosin staining and double immunohistochemical staining using CK19 and D2-40 were used to determine peripancreatic neural invasion and lymphatic vessel invasion (LVI) in peripancreatic neural plexus tissues. Results D2-40 immunohistochemistry showed brown-yellow tube-like lymph vessels. The lymph vessel of peripancreatic nerve plexus followed vascular and perineurium, and the lymph vessel adjacent to peripheral nerve fascicles owned tube-like structure. CK19 immunohistochemistry showed cytoplasm of pancreatic cancer cell was red. The LVI was observed in lymphatic capillaries. Peripancreatic neural plexus invasion was found in 30 cases (68.2%), tumor cell invading presented in lymph vessels of peripancreatic neural plexus in 21 patients (47.7%) with pancreatic cancer. The peripancreatic neural plexus invasion was associated with LVI (P=0.003). The plexus of pancreatic capitalis and celiac plexus were respectively confirmed to be the spot with the highest lymphatic vessel density and the maximal incidence of neural plexus invasion simultaneously. Conclusions Patients with pancreatic cancer should be given the opportunity of radical operation combining related peripancreatic neural plexus as far as possible. The dual immunohistochemical staining with anti-CK19 and anti-D2-40 monoclonal antibodies should be a new method in research of perineural invasion of pancreatic cancer, exhibiting both the pancreatic cancer cells and lymph vessels clearly and distinctly.