Nerve Plexus Invasion Research Articles

Extrapancreatic nerve plexus invasion by carcinoma of the head of the pancreas

The intraportal endovascular ultrasonography (IPEUS) could diagnose the second portion of the extrapancreatic nerve plexus invasion and provide precise information in operative strategy. But, the first portion was not visualized clearly owing to poor tissue penetration of the ultrasound beam, which may have reduced diagnostic accuracy. Improvement of the scanning area is expected to make intraportal endovascular US even more useful. Pancreatic cancer easily invades the retroperitoneal tissue, especially the extrapancreatic nerve plexus. We evaluated the extrapancreatic nerve plexus invasion of the pancreatic cancer with IPEUS. IPEUS was performed intraoperatively in 20 consecutive resected cases with carcinoma of the head of the pancreas. IPEUS was performed with an 8-French, 20 MHz intravascular ultrasound catheter. IPEUS visualized the inferior pancreaticoduodenal artery (IPDA) in the extrapancreatic nerve plexus. The high-echoic area around the IPDA corresponds to the second portion of the extrapancreatic nerve plexus. The sonographic criterion for detection of the extrapancreatic nerve plexus invasion is low-echoic infiltration around the IPDA. Extrapancreatic nerve plexus invasion was confirmed with resected specimens in 10 patients. The IPDA could not be visualized in two patients. In 18 patients, the diagnostic accuracy of invasion was evaluated. For diagnosis of extrapancreatic nerve plexus invasion with intraportal endovascular US, the sensitivity, specificity, and overall accuracy were 87.5, 90, and 88.7%, respectively.

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.