Background. Pleomorphic carcinoma of the pancreas is a rare tumor with an extremely poor prognosis. The mean survival time is reported to be approx 3 mo. Clinical and Histological Findings. A 56-yr-old Japanese man presenting with general fatigue, loss of weight, and high fever was found to have a large hypervascular mass in the body of the pancreas with regional lymph node metastases. Laboratory investigation revealed leukocytosis, elevated erythrocyte sedimentation rate (ESR), and high serum C-reactive protein (CRP). In addition to distal pancreatectomy, splenectomy and lymph node dissection were performed. Histology showed the presence of pleomorphic large cells with bizarre mono- or multinuclei, growing in sarcomatoid pattern without mutual cohesiveness. Another noticeable finding was massive lymphocytic infiltration of the stroma of the neoplasm. Immunohistochemically, the infiltrating lymphocytes consisted of cytotoxic type of T cells. In addition, in situ hybridization for Epstein-Barr virus-encoded RNA (EBAR-1) was not seen in the tumor cells or in lymphocytes. After surgery the patient did not undergo chemotherapy or radiotherapy. He has been well without recurrence for 8 yr. Conclusion. We report a case of pleomorphic carcinoma, possibly lymphoepithelioma-like carcinoma, of the pancreas with massive lymphocytic stromal infiltration and long-term survival after resection. Cytokine responses and cellular immunoreactivity may have contributed to a long-term survival, which is unusual in the common type of pleomorphic carcinoma of the pancreas.