[Involvement of lymph nodes and neural plexus in carcinoma of the pancreas]

We studied 428 lymph nodes attached to the head of the pancreas (13,14,17) in 18 patients with ductal carcinoma of the pancreatic head. These were classified into the small size of the lymph nodes less than 5mm (group S), the moderate size of the lymph nodes (group M) and the large size of the lymph nodes more than 10 mm (group L). The metastases were seen in 76 nodes, which consisted of 49 with group S, 14 with group M and 13 with group L. The lymph node involvement in group (14) S was found in 7 of 18 patients (38.9%), that in group (14) M was in 4 (22.2%) and that in group (14) L was in 2 (11.1%). In these involved cases, the primary tumors tended to be locate in the portion near the superior mesenteric artery, such as in the uncinate process. Invasion of extrapancreatic neural plexus was noted in 9 of 18 patients (50%). There was no significant correlation between nerve plexus invasion and lymphatic invasion by Spearman's rank correlation. In addition, any close relationship between plexus invasion and primary tumor location could not be indicated. These results suggested that neural invasion in pancreatic carcinoma is independent of lymphatic invasion, and the routes of cancer spread via the neural plexus are different from those via the lymphatic vessels. Those without liver metastases survived longer than those with liver metastases, which were characteristically multiple.