The accessory spleen: prevalence and imaging findings in 1,735 consecutive patients examined by multidetector...

To analyze the prevalence and CT findings of accessory spleens in the normal population.

CT-examinations of 1735 consecutive patients, all examined by triple phase 16-row multidetector computed tomography (MDCT) of the abdomen, were retrospectively analyzed with special emphasis on the presence, location and imaging aspects of accessory spleens.

199 patients showed an accessory spleen (11%). Size of accessory spleens ranged from 3 to 20 mm (mean 10 mm). In 60% the accessory spleen was located at the level of the splenic hilum and in 33% at the level of the lower pole. In 46% the accessory spleen was located medially and in 43% ventrally. 19 patients presented with two (1.1%) and seven patients with three accessory spleens (0.4%), respectively. One patient showed splenosis and one patient showed an enlarged accessory spleen (5 cm) secondary to a splenic apoplexy (i.e. hemorrhagic infarction) of the accessory spleen, caused by torsion.

Accessory spleens may be identified by MDCT in about 11% of patients. Familiarity with normal imaging findings and knowledge on differential diagnoses, possible pathologies and potential pitfalls helps to differentiate from other findings in the upper abdomen.