Cystic Diseases of the Kidney

*Common type of cystic disease of the kidney Introduction Cystic diseases of the kidney are common lesions worldwide.1–5 They are broadly divided into genetic and nongenetic cysts. A renal cyst is a fluid-filled sac arising from dilatation in any part of the nephrons or collecting ducts. The cysts may eventually separate from the nephrons or ducts and continue to enlarge. Although most are simple cysts, about one-third of people older than 50 years of age are said to have renal cysts.1–3 Depending on the type, symptoms can occur at any age, and many cases may manifest symptoms in utero. Undiagnosed or untreated cases ultimately progress to end-stage renal disease (ESRD) and death. The outcome of the disease varies between developed and developing countries, due mainly to late presentation, lack of facilities required for prompt diagnosis, and a lack of facilities and manpower required for intrauterine interventions in developing countries, especially in children who manifest symptoms in utero.3 Table 88.1 shows the classifications of cystic diseases of the kidney. This chapter discusses the common types, which include: • multicystic kidney or multicystic dysplastic kidney (MCDK);