Background: Anaplastic carcinomas of the pancreas are rare aggressive tumorswith survival measurable in weeks. Many terms have been applied used to describe these tumors, and anaplasticfoci are identified in ductal adenocarcinomas and in ectopic pancreata, but are not the dominant patternof growth. We herein present our experience with a case of anaplastic carcinoma of the pancreas withsquamous features in order that allowed us to delineate the clinicopathologic and immunohistochemicalfeatures of this rare entity. Case Report: According to imaging findings, the 77-year-old Japanese manwas diagnosed as the malignant pancreatic tumor, and underwent a surgical resection. Histopathologically,anaplastic tumor cells showed focal ductal and squamous features infiltrated into pancreatic parenchyma,extrapancreatic fatty tissue, and stomach. The tumor cells showed strong reactivity for cytokeratin,alpha-SMA, vimentin, NSE, and S-100 protein. Although immunoreactivity against p53 was negative, strongpositive immunostaining for proliferating cell nuclear antigen and interleukin-1 receptor type I (IL-1RI)was observed in a the majority of tumor cells, while the alpha(6) integrin subunit was predominantlystrong expressed in the adenocarcinomatous lesion. The patient's postoperative course was uneventfuland he was treated with a chemotherapy consisting of gemcitabine. After discharging from the hospital,he had subsequently been observed as an outpatient and same chemotherapy was followed by weekly. However,the patient suffered from peritonitis carcinomatosa and re-increases of multiple liver metastases, andhe died in the fourteenth month after surgery. Conclusions: Our immunohistochemical studies suggestedthat the prognosis of the case with anaplastic carcinoma presented here would be poor, due to the strongexpression of integrins and IL-1RI.

Keywords: Carcinoma, Squamous Cell - diagnosis, Carcinoma - surgery, Fatal Outcome, Integrins - analysis, Pancreatic Neoplasms - surgery, Peritoneal Neoplasms - secondary, Receptors, Interleukin-1 - analysis, Tumor Markers, Biological - analysis