[Acquired renal cystic disease].

In 1977, Dunnill et al. described a new disorder, bilateral multiple renal cystic disease. It occurred among hemodialysis patients whose original illness had not been cyst-related. Acquired cystic disease of the kidney (ACDK) is commonly observed in patients undergoing hemodialysis. The incidence of ACDK is 40-50% in reports of autopsy and surgical specimens, rising to more than 90% after 5-10 years of dialysis. The volume of the kidneys decreases in the first 3 years of dialysis and then increases as the rate of cyst formation increases. In male patients undergoing long-term hemodialysis the incidence of ACDK is markedly high. ACDK is also found in patients before hemodialysis. The primary concern in patients with ACDK is the increased incidence (5-19%) of renal cell carcinoma (RCC). The incidence is about twelve to eighteen times higher than that in the general population and the cancers may be asymptomatic. Therefore, screening is essential if carcinomas are to be detected early. Regular screening by ultrasonic examination or CT scan is needed. A patient requires nephrectomy when the kidney cancer exists or is suspected by dynamic CT scan. Nephrectomy is performed only on the side with renal mass. It has been argued that RCC associated with ACDK are innocuous and do not predispose the patient to an increased risk of death from RCC. RCC arising from ACDK is considered to be a tumor of low malignant potential, compared with classic RCC. However, RCC has been reported to metastasize in 16% of the patients on dialysis and to be the cause of death in 2% of the kidney transplant recipients. The etiology of ACDK is unclear and its incidence increases with the duration of dialysis. ACDK patients have a propensity to develop adenocarcinoma. The increased incidence of RCC in ACDK patients warrants careful radiologic monitoring of end-stage kidneys in selected patients.