Benign epithelial cyst of the spleen with a high production of carbohydrate antigen 19-9.

A rare case of an epithelial splenic cyst showing a high production of the carbohydrate antigen 19-9 (CA19-9) is presented. A 19-year-old female with high fever and loss of appetite was diagnosed as having a splenic cyst. Laboratory data revealed unusually elevated serum levels of both CA19-9 and CA125. The histological diagnosis was an epithelial splenic cyst, and immunohistochemically the wall of the splenic cyst was strongly positive for CA19-9 and slightly positive for both CA125 and CEA. Fluid in the splenic cyst contained quite high levels of CA19-9, CA125 and CEA. After splenectomy, the serum levels of CA19-9 and CA125 gradually decreased. These findings suggested that the splenic cyst produced CA19-9, CA125 and CEA. And with very high levels of CA19-9 and CA1 25 in the cyst, some had entered into systemic circulation.