Re-evaluation of histological findings of nonparasitic splenic cysts

Objective: The pathogenesis of nonparasitic splenic cysts (NPSCs) has not been clarified completely. The aim of this multinational and multicentre retrospective study was to further elucidate the origin of NPSCs. Methods: From 1980 to 2006, 50 children and adolescents were surgically treated for NPSC at six paediatric surgical centres in four European countries. The initial histology report of 35 NPSCs, 22 epidermoid cysts, 11 pseudocysts or post-traumatic cysts and two mesothelial cysts was available. Additional re-evaluation, including immunohistochemistry, to detect cytokeratin, carcino-embrionic antigen and mesothelioma antibody in the inner surface of the cysts was carried out. Special attention was given to the possibility of preceding trauma to the splenic area and whether it played a role in the genesis of NPSC. Results: The pathological re-evaluation showed 30 epidermoid cysts, four mesothelial cysts and one pseudocyst. Immunohistology revealed eight epidermoid and two mesothelial linings of the cysts in those 11 patients in whom pseudocyst was diagnosed originally. No pseudocyst was documented in those patients who had a history of previous blunt abdominal trauma but was not proved by ultrasound and computed tomography scan. Conclusion: In contrast with the prevailing belief, it has been demonstrated that NPSCs are congenital in origin, and there is no clinically proven evidence that trauma does play a role in their genesis.