Simple cysts are the most common cystic diseases of the kidney. Its incidence increases with age. Simple cysts are encountered in 25% of patients over the age of 50 who undergo abdominal computed tomography examination for reasons other than urological reasons. In large autopsy series, it is reported that up to 50% of simple cysts are seen. Simple cysts can be single or multiple. Sometimes it is bilateral. It can be located in the cortex or medulla.
The pathogenesis of simple cysts is unknown. It is thought by some authors that it develops as a result of tubular obstruction. Reporting that the incidence of simple cysts increases in cases of obstructive pathologies such as prostate hypertrophy supports this view. In contrast, microdissection studies suggest that simple cysts develop from diverticula in tubular or collector ducts.
Simple cysts are often asymptomatic and are discovered incidentally during another examination. It can reach large volumes and cause pain. In addition, bleeding into the cyst or cyst infection may occur. Cysts that have reached very large volumes may cause hypertension by causing an increase in renin secretion as a result of compression on the surrounding tissue.
Cysts can be easily seen with ultrasonographic examination. If multiple simple cysts are present in both kidneys, they should be differentiated from autosomal dominant polycystic kidney disease. For this purpose, a detailed family history should be taken and the presence of cysts in other organs should be investigated. Simple cysts, unlike polycystic kidney disease, do not cause renal dysfunction. Sometimes it may be necessary to differentiate from renal carcinoma and abscess. The ultrasonographic appearance of simple cysts is typical. Its borders are smooth and its interior is anechoic. Suspicious cases require computed tomographic examination. Simple cysts can grow very slowly over time.
Asymptomatic cases do not require any treatment. Cysts that have reached very large volumes can be aspirated and a sclerosing agent such as alcohol injected. Or it can be excised laparoscopically.