Can accessory splenic tissue or splenosis be detected via nuclear medicine procedures?
After splenectomy as treatment of idiopathic thrombocytopenia, approximately 30% of adult patients can result in treatment failure, which may be secondary to an accessory spleen or splenosis. Unrecognized splenosis may also be a cause of unexplained abdominal pain or present as an abdominal or pelvic mass on CT. The most sensitive imaging procedure for localization of small foci of splenic tissue is the heat-damaged 99m Tc-RBC scan, because damaged RBCs localize in splenic tissue intensely and specifically. This is the procedure of choice, especially if SPECT is used. However, the RBC-damaging process requires additional laboratory manipulation and may not be readily available in many clinics. It is therefore reasonable to perform a liver-spleen scan as an initial study and, if it is positive for splenic tissue, to institute appropriate therapy. If it is negative or inconclusive, a heat-damaged RBC study should be performed.