Clear cell carcinoma of the pancreas--a case report and review of the literature.

Most of the malignant neoplasms of the pancreas demonstrate features that are consistent with adenocarcinoma. According to the WHO classification, primary clear cell carcinoma of the pancreas is rare and it is classified as a "miscellaneous" carcinoma. In addition, there is not an adequate systematic overview that can demonstrate its true existence as a definable entity. We report here on an unusual case of primary pancreatic clear cell carcinoma, which is the first such reported case in Korea. A 66 year old woman presented with abdominal pain and significant weight loss over the previous three weeks. On the abdominal computed tomography (CT), we detected an abdominal mass involving the pancreas tail and liver, and clear cell carcinoma with rhabdoid feature was seen on the histologic evaluation. The tumor cells showed well defined cell membranes, clear cytoplasm and prominent cell boundaries. The immunohistochemical stains showed positive reactions to antibodies against pan-cytokeratin, cytokeratin 7, carcinoembryonic antigen (CEA) and epithelial membrane antigen (EMA). On the other hand, there was a negative reaction for cytokeratin 20, chromogranin, synaptophysin, smooth muscle actin and HMB-45. She was diagnosed with a primary pancreatic clear cell carcinoma with hepatic metastasis and she received palliative gemcitabine chemotherapy. The patient died one month later of pancreatic cancer progression.