Prevalence of accessory spleen and its features in abdominal CT scan

Given the different prevalence of accessory spleen in previous studies and no information about its rate of detection and also its known side effects, this study was designed to determine the prevalence and associated factors of accessory spleen among patients referred to a CT scan center in Tehran between 2008 and 2010. In this cross- sectional study, all patients with different indications of abdominal CT scan with the CT multidetector were studied. Frequency of accessory spleen in abdominal CT scan was evaluated and its prevalence with 95% confidence interval in the population was estimated. Characteristics of the accessory spleen, including size, density, shape and location, were evaluated. prevalence accessory spleen in 851 eligible patients was 10.6%. Mean (± SD) age was 55.5± 13.3 years and 55.6 percent were women. One hundred eleven spleens were detected in 90 patients. In 90.1% of cases, size of accessory spleen was more than 10 millimeter. Majority of cases which includes 60% of them were located next to hilum. Also, 90.1% of cases were isodense. It seems that prevalence of accessory spleen in Iran is less than other countries. Although uncomplicated accessory spleens are asymptomatic and incidentally discovered, radiologists should be aware of accessory spleens and their characteristics and should consider them in the differential diagnosis of unclear perisplenic masses.