We report the case of a 30-year-old woman with a benign epidermoid splenic cyst and a high CA 19-9 serum level (268 U/mL). The patient underwent resection of the cyst and splenectomy. After removal of the cyst, the serum CA 19-9 level decreased to a normal level within 6 weeks. True non-parasitic splenic cysts are rare. Approximately 30 cases of benign true splenic cysts with a high CA 19-9 serum level have been published.