Dermoid cyst of the spleen: report of a case.

A rare splenic dermoid cyst in an 11-year-old girl is reported herein. The patient was referred to us with the chief complaint of acute-onset abdominal pain. The lesion was demonstrated by ultrasonography, computed tomography, and magnetic resonance imaging to be a cystic lesion containing serous fluid. A splenectomy was performed. Both histopathological and immunohistochemical findings demonstrated the cyst to be a dermoid cyst of the spleen. To avoid the risk of infection following splenectomy, polyvalent pneumococcus vaccine was administered. The patient recovered uneventfully. We performed immunohistochemical studies with cytokeratin and electron microscopy to determine the origin of the cyst.