A splenic pseudotumor: an accessory spleen.

We encountered a case of splenic pseudotumor. It contained a cystic portion, and the solid portion of the mass showed much higher vascularity than the proper spleen on dynamic CT. An accessory spleen was considered most likely, but the differential diagnosis still included malignant lymphoma and metastatic tumor. The diagnosis was obtained by technetium-99m Sn colloid scintigraphy.