Giant epithelial cyst of the accessory spleen

Splenic cysts are uncommon, and cysts derived from the accessory spleen are rare. We report a case of a huge splenic cyst derived from the accessory spleen in the omentum, concomitant with multiple epithelial cysts of the primary spleen. Both serum and cystic fluid concentrations of carbohydrate antigen (CA)19-9 were markedly elevated. A huge monolocular cyst occupied the entire abdomen. A total of 7 l of aspirated cystic fluid was turbid and yellowish-brown. The cyst wall, which consisted of CA19-9-positive squamous epithelium, contained approximately 2 × 3 × 1 cm of splenic tissue. There was a separate multicystic 16 × 8-cm spleen in the normal position. The CA19-9 serum level returned to normal postoperatively.