Heat-damaged red cell scan for intraoperative localization of the accessory spleen.

Destruction of platelets by the reticuloendothelial system in immune thrombocytopenia purpura (ITP) is enhanced by platelet-associated IgG. Relapse after splenectomy may result from IgG produced in the accessory spleen. These structures may be located at any site between Gerota's fascia and the left ovary or testicle as well as adjacent to the spleen. The heat-damaged red cell scan (HDRCS) has been demonstrated to be an accurate method for identifying accessory spleens. HDRCS using semi-in vitro labeling of the patient's red blood cells with technetium 99m pertechnetate delineated accessory splenic tissue as the etiology of post-splenectomy relapse three times in two patients 3 to 9 months postoperatively. A labeled intraabdominal probe and HDRCS were subsequently used by the surgical team for identification and excision of the accessory spleen. Four additional patients underwent splenectomy for ITP between 1989 and 1992; heat-damaged red blood cells were injected after the major splenic tissue was removed. Accessory spleens were identified in two patients. All patients were discharged within 6 days, without perioperative complications. Two patients currently require steroids. The techniques of intraoperative HDRCS allow rapid localization and removal of the accessory spleen at the time of laparotomy. Evidence of growth of accessory splenic tissue postsplenectomy was demonstrated.