Incidental Finding of Accessory Spleen on Bone Scintigraphy

The case of a 42-year-old woman with hereditary spherocytosis whose spleen was removed in infancy is reported. A bone scan, which was performed during the staging of a hepatocellular carcinoma showed a mass concentrating MDP laterally to the upper pole of the left kidney. CT and US raised the suspicion of a renal mass. Dynamic scintigraphy with DTPA showed the mass to be highly vascular, but probably not of renal origin. The surgically removed mass was a calcified accessory spleen. The history of splenectomy in infancy made the preoperative diagnosis almost impossible, but the nuclear medicine procedures were more accurate than the radiological procedures in the diagnosis towards an extrarenal mass that was well perfused and calcified.