[A case of congenital unilateral multicystic kidney with renal matrix calculi].

A forty-two-year-old man was seen with right lumbar pain. Physical examination revealed a right flank mass. Conventional excretory urography showed lack of right renal function, whereas left kidney was visualized. Right nephrectomy was performed. A cluster of several different sized cysts was disclosed in the right renal region. The renal surface was smooth. The removed kidney weighed 1,150 g. The ureter was completely obstructed at the ureteropelvic junction. Cysts were filled with matrix calculi. Pathological examination showed dysplastic glomeruli and primitive tubules within loose embryonic mesenchyme between two cysts whose walls consisted of smooth muscle strands and connective tissue. The final diagnosis was a congenital unilateral multicystic kidney with renal matrix calculi. The multicystic kidney is the most common form of renal cystic disease in infancy. However, few cases in adults have been reported. The diagnostic approach, treatment and outcome of a congenital unilateral multicystic kidney are discussed.