[A case of a congenital unilateral multicystic kidney and a review of 126 cases in Japan].

A 3-year-old boy was admitted to our hospital with complaints of left flank mass and growth retardation. Examinations with IVP (Fig. 1), retrograde pyelography (Fig. 4) and cystoscopic examination (Fig. 3) showed a left nonopacified kidney, and right hydroureteronephrosis due to stenosis of the midureter. Two large cystic patterns were found in the left kidney by ultrasonic scanning tomography (Fig. 2); and, the left kidney was found to be occupied by a round and homogeneously low density mass by CT scanning (Fig. 6). The left renal artery was not demonstrated on the aortogram (Fig. 5). The patient was diagnosed to have a left congenital unilateral multicystic kidney, and laparotomy was performed. The left kidney was easily removed, and the part with stenosis in the right ureter was removed, then end-to-end anastomosis was performed. Grossly, two large cysts (upper and lower part) and connective tissues were found in the left kidney (Fig. 7), and the vessels of the renal pedicle were filiform. No luminal formation of the renal pelvis or ureter was found. The epithelium of the cyst wall (Fig. 8) was deciduated leaving the connective tissue and smooth muscle, as shown by the histological examination. Histological examination of the parenchymal tissue (Fig. 9) between the two cysts showed primitive glomeruli and renal tubules among abundant connective tissue, but no cartilage tissue. Statistic examination and discussion have been made of 126 cases of congenital multicystic kidney reported in Japan.