A case of huge retroperitoneal accessory spleen

A 50-year-old man was referred to our hospital for the management of incidentaly detedted retroperitoneal mass. A contrast enhanced CT scan showed a large ovoid mass with homogeneous enhancement associated with surrounding soft tissue change. The mass showed homogeneous enhancement on contrast enhanced MRI, and showed relatively high intensity in diffusion weighted image. Since a possibility of malignant retroperitoneal tumor could not be ruled out, surgical resection was performed. Pathlogical examination showed the accessory spleen without malignant tissue. We report this rare case of a huge retroperitoneal accessory spleen.