MR Features of Abdominal Splenosis

493 he term “splenosis” was defined by Buchbinder and Lipkoff [1] in 1939 as the heterotopic autotransplantation of splenic tissue. Splenosis occurs after trauma or surgical procedures of the spleen and thus differs from congenital entities such as accessory spleen or polysplenia. Splenosis was once considered to be uncommon because patients are usually asymptomatic. However, it has been suggested that the occurrence of splenosis in patients after traumatic splenectomy is from 16% to 67% [2]. Splenosis is usually found incidentally on imaging studies. The unexpected location, irregular shape, and slow growth of a splenic implant may mimic a neoplasm. Lack of awareness of the imaging findings and inadequate knowledge of patient history may lead to misdiagnosis and unwarranted surgical intervention [3]. Splenic scintigraphy with technetium-99m–tagged heat-damaged RBC is frequently used to confirm the diagnosis [4]. Nevertheless, the imaging characteristics of splenosis have been reported to be nonspecific and are seldom reviewed in the radiology literature. We discuss the MR features of splenosis. Method Review of the databases of the nuclear medicine and surgery departments at our institution from January 1994 to December 2001 identified eight patients who had undergone splenectomy and had intraabdominal splenic implants. Splenosis was confirmed by excisional biopsy ( n = 1) and a splenic scan with 99m Tc-tagged heat-damaged RBC ( n = 7). The location, shape, number, growth, and characteristic enhancement pattern of splenosis in these eight patients on dynamic MR images are reviewed.