Prevalence of ultrasound-diagnosed asymptomatic simple renal cysts at the University College Hospital, Ibadan

Background: Renal cysts are thin-walled sacs of fluid that form within the renal parenchyma which may be simple or complex. Most simple renal cysts are asymptomatic and are found usually incidentally by ultrasonography and computed tomography. However, a small proportion may become symptomatic with pain being the most common symptom. The aim of the study is to determine the prevalence of asymptomatic simple renal cysts in patients presenting for abdominal ultrasound (US) and the associations of simple renal cysts with age and gender. Materials and Methods: This was a retrospective study which involved the retrieval of the results of abdominal US performed at the Radiology Department of the University College Hospital between January 2013 and December 2015. Data extracted included age, sex, and renal sonographic findings. The retrieved data were analyzed using Statistical Package for the Social Sciences (SPSS) version 20.0 software. Results: Two thousand and ninety-five patients had abdominal US done during the study period. The overall prevalence of asymptomatic simple renal cysts was 2.3% with the prevalence increasing with age (P < 0.001). Simple renal cysts were found in 2.3% of both males and females with a male-to-female ratio of 1:1.3. The mean widest diameter of renal cysts was 45 mm with a range between 15 mm and 105 mm. The cyst diameter tended to increase with age, but the correlation with age was not statistically significant (P = 0.278). The majority of the cysts were solitary (87.8%) with the right kidney having majority (59.2%) of the cysts. Conclusion: The overall prevalence of simple renal cyst in our study is 2.3% and it increased with age. Since simple renal cysts have been associated with some conditions and complications such as hypertension, polycythemia, hemorrhagic transformation, and cyst rupture, adequate follow-up is necessary to enable the prompt detection of complications and adequate intervention if the need arises.