A Comparison of the Pathological Types of Undifferentiated Carcinoma of the Pancreas

Objectives This study aimed to identify the detailed clinicopathological features of undifferentiated carcinoma of the pancreas (UCP). Methods We investigated clinical, imaging features and the prognoses of 261 patients; 8 were our patients, and the remainder were identified by searching English-language articles in PubMed. Results We classified patients with UCP into 3 types based on pathological findings: osteoclast-like giant cell-associated carcinoma, pleomorphic cell carcinoma (PLC), and spindle cell carcinoma. There were no remarkable differences in clinical, radiological features between these 3 types. However, PLCs were significantly more likely to be unresectable than were the other 2 types (P < 0.001). Patients with osteoclast-like giant cell-associated carcinoma achieved the best overall survival (OS) rates (P < 0.001), whereas those with spindle cell carcinoma had significantly longer OS rates than did those with PLC (P = 0.004). These OS patterns were maintained when considering only those patients who underwent resection. Patients with PLC had both lower curative resection and high lymph node metastasis rates (P = 0.029, P = 0.023). Patients who underwent resection had more favorable prognoses than did those who did not. Conclusions Surgery is the first choice for resectable UCP. Pleomorphic cell carcinoma is particularly malignant; postoperative treatment should be introduced immediately.