A true splenic cyst producing carbohydrate antigen 19-9 and cancer antigens 50 and 125, but not interleukin 10.

A giant cystic lesion of the left upper abdomen associated with a smaller ovarian cyst in a young female patient is reported. Laboratory data revealed elevated serum levels of carbohydrate antigen 19-9 (CA 19-9), carcino-embryonic antigen (CEA), cancer antigens 50 and 125, and tissue polypeptide antigen. In contrast, the serum levels of interleukin 10, a cytokine involved in modulating immune responses and produced by many cancer histotypes, were normal. Since ovarian cancer or cystic adenocarcinoma of the tail of the pancreas were not ruled out, the patient underwent laparotomy. After splenectomy and ovariectomy, the tumour marker serum levels normalized. Histology and immunohistochemical analysis revealed a true splenic cyst with the inner epithelium strongly positive for CA 19-9 and CEA and high levels of cancer antigens in the fluid. The ovarian lesion was a serous cystadenoma. The inner epithelium showed no immunoreactivity for tumour markers which were not measurable in the fluid. True cysts of the spleen are rare; in a few cases, high serum levels of CA 19-9 and CEA have been reported. In such instances, cyst resection or splenectomy is indicated to rule out malignant lesions and to remove the cancer antigen producing epithelium. The reported case shows that the epithelium lining true splenic cysts may produce, besides CA 19-9 and CEA, other tumour markers, in particular cancer antigens 50 and 125. In addition, normal serum values of interleukin 10 correctly predicted the benign nature of the lesion.