Patterns of neural and plexus invasion of human pancreatic cancer and experimental cancer.

Specimens from four patients who underwent resection of cancer of the pancreatic head were examined histologically by serial sections to study the patterns of extrapancreatic nerve plexus invasion of cancer. To understand the mode of neural invasion and its specificity for pancreatic cancer, we also examined retropancreatically transplanted virus-induced rabbit papilloma (VX2) cells in six rabbits. Histological evaluation of the specimens from patients revealed neural invasion near the primary lesion, where cancer cells broke the perineurium and showed communication of cancer cells between the inside and outside of the perineurium. Tumor cells found distant from the primary cancer were confined to the perineurium, grew in a continuous pattern, and followed the branches of nerves. When the rabbit's VX2 cells were implanted into the retropancreatic region of recipient rabbits we also observed neural invasion. This study shows that neural invasion is a common, but not a specific, feature of pancreatic cancer, and it suggests that en bloc excision of the retropancreatic tissue, including fat tissue and the extrapancreatic nerve plexus, should be the basic procedure of radical surgery in the treatment of pancreatic cancer.