To analyze the implication of retroperitoneal perineural lymphatic infiltration (rpli) for the survival of patients affected by exocrine pancreatic cancer, we considered 17 cases which underwent radical resection at our Institute from 1980 to 1993. Histology of specimens showed an rpli in 15 cases, without any correlation between this anatomopathologic aspect and the neoplasm size or the presence of lymph node metastases. The 2 patients without rpli are both alive and have been free from disease during a follow-up period of more than 5 years. In the group of 15 patients with positive rpli, 3 (21.4%) have remained free from disease (2 alive and 1 dead for other reason). Eleven remained with disease (1 is alive and 10 have died). One died in the postoperative period and could not be included in the evaluation. These observations have led the surgeon to consider the necessity, during resection, of an accurate dissection not only of the regional lymph nodes but also of the retropancreatic tissue and the neural structures present in this area. This approach may lead to a more correct staging of the neoplasia, a better radical surgery and perhaps a longer survival. Moreover it may represent an important marker for an adjuvant protocol of chemotherapy and/or radiotherapy.