gms | German Medical Science

Aims: Pancreatic carcinoma is frequently associated with lymphangiosis carcinomatosa and lymph node metastasis; however, so far it has not been studied whether pancreatic carcinomas are able to induce the formation of new lymphatic vessels. We therefore assessed the number of lymphatic vessels at the tumor margin and compared it with non-neoplastic pancreas and areas of fibrosis in the same specimens.

Methods: So far 33 patients with curatively resected carcinomas of the head of pancreas were studied by immunohistochemistry for Podoplanin, a specific marker for lymphatic endothelial cells. We counted the number of lymphatic vessels at tumor margin, in areas with fibrosis without tumor and in the preexisting pancreas (magnification 400x, per 10 HPF). For statistical analyses Shapiro-Wilks-Test and Wilcoxon-Test were performed.

Results: The median numbers of lymphatic vessels were: 3 lymphatic vessels (LV) per 10 HPF in the preexisting pancreas, 20 LV/10 HPF in fibrosis without tumor and 21.3 LV/10 HPF at the tumor margin. The differences in LV density between both fibrosis and tumor margin versus preexisting pancreas were highly significant (p<0.001), whereas the data for fibrosis and tumor margin were almost identical (p=0.985).

Conclusions: Lymphatic vessel density is increased in pancreatic carcinomas. This phenomenon seems to be part of the general peritumoral inflammatory reaction and not a result of a specific tumor-cell effect. Further investigations are in progress which (1) correlate the results with the expression of VEGF-C and VEGF-D in pancreatic carcinomas and (2) compare the observations with the lymphatic vessel density in granulation tissue and chronic pancreatitis.