Accessory Spleen

Accessory spleens are masses of additional splenic tissue. They represent by far the most common congenital abnormality of the spleen. Accessory spleens are round small masses that resemble splenic structure. They may be located anywhere in the abdomen, but the most common sites are near the splenic hilum and the tail of the pancreas. Intrapancreatic accessory spleen can mimic a neoplastic mass. Other possible locations are along the splenic vessels, in the gastrosplenic and splenorenal ligaments, in the mesentery, and in the omentum. Any accessory splenic tissue may become hypertrophic. When splenectomy is performed for hypersplenism, hypertrophy of an accessory spleen may cause recurrent disease. Ectopic splenic tissue may mimic neoplasms and lymphadenopathies. Ectopic splenic tissue shows imaging features identical to those of the normal spleen at US, CT, and MR. The enhancement pattern, especially the characteristic inhomogeneity in the arterial phase, is very specific. The use of...