[Multicystic kidney in the newborn]

Fourteen cases of multicystic kidney were identified out of 153,825 births through five and a half years at the "Dr. Ignacio Morones Prieto" hospital in Monterrey, Nuevo León. The etiopathogenesis and heredity in this disease are not clear. An early diagnosis is possible following a careful abdominal examination. The left kidney is the one most frequently involved. The excretory urography only shows renal exclusion of the affected side; when the disease is of only one side there is good excretion of the opaque medium by the contralateral kidney. The kidney is substituted by an irregular mass made up of multiple cysts losing the aspects of a normal kidney. Microscopically, its architecture is completely lost and there is replacement by cysts and some occasional hypoplastic glomeruli. If the opposite kidney is not affected, the prognosis is good. Nephrectomy must be done. Differential diagnosis must be made with hydronephrosis, nephroblastoma and thrombosis of the renal vein.