A clinicopathologic study on neural invasion in cancer of the pancreatic head.

Thirty-four patients who had resection of cancer of the pancreatic head were examined clinicopathologically to elucidate neural invasion of cancer of the pancreatic head to the extrapancreatic nerve plexus. Invasion of cancer to the retropancreatic tissue (rp+) was observed in 29 (85%) of the 34 patients, and neural invasion to the extrapancreatic nerve plexus was observed in 21 (72%) of the 29 patients with rp+. The incidence of invasion to the second region of the nerve plexus of the pancreatic head was high (14 patients; 67%). The degree of the neural invasion tended to increase as the intrapancreatic neural invasion became more severe and lymph vessel invasion more marked. Based on these findings, en bloc resection of the retropancreatic tissue involving the nerve plexus and fat tissue is necessary in the surgical treatment of cancer of the pancreatic head.