True spleen cysts are uncommon and rarely associated with elevated serum and intracystic tumor markers CA 19-9 and CEA levels. A 19-year-old woman with a left subcostal mass was observed. Echinococcus granulosus serology was negative, and serum tumor markers CA 19-9 and CEA levels were 273 kU/L and 33 ng/mL, respectively. CT-scanning showed a splenic cyst of 18 cm in greatest diameter. The patient underwent total laparoscopic splenectomy and the serum tumor markers progressively decreased and became normal three months after surgery. Splenic cysts derive from an invagination of the splenic capsule in the splenic pulp with a subsequent squamous metaplasia. This last evidence could be confirmed from the variable cellular differentiation lines of the mesothelial squamous cells in the cyst wall. We should not exclude a higher degenerative potential of cystic epithelium that produces de-differentiation proteins. The lowering of the serum levels of the two markers after the cyst removal is witness of the direct relationship between the increment of the serum tumor markers and the presence of the epidermoid cyst.