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A Theoretical Consideration of Renal Dysgenesis
TnE Jm:rR'UL OF Unrn:.,(JGY
l\'ovenlber & Wilkins
A THEOllETlCAL CONSIDERATION OF RENAL DYSC}ENESIS H. MELVI:\J RADJ\IAN
AND
Fr()}n the Department of Obsielr'ics,
ALBERT E. GOLDSTEIN
For Thr: Women
Rec:ently Doroshow ancl Abcshouse 1 presented review of congenital unilateral solitury kidney with a rc:port of 37 cases ancl a survey of the literature. }n their explanation of some of the causes that produce renal agem,sis, they referred to the vrnrk of several iuvestigators. 2 • 8 In substance one of the theories rc1·olved about development de·· of the ureter. According to Campbell;1 derivation of the kidney depends upon three structmes: 1) the 2) the mesonephros and 3) the met:mephros. 'The pronepbros which degenerates the fourth w1:ek is a remnant of the cxcrdor,v in lower vertebrates. It develops independently as 6 to 10 of tubules with a primary excretory duct opening into the coclomic . The mesoncphrns appears just lmfore the pronephros disappears and consists of tubules emptying into the meRonephric duct. Regression occurs in 12 to 14 weeks. During mcsoncphric or true kidney degeneration, the appears. The commonly accepted theory for the cornabsence of the kidney is the: failure of the wolffian duct to off a (:01,rcsponding uretnal bud after the duct has reached the cloaca. The mechanism. by which the rncsoclerm of the lower encl of tlw ncphrogenic ridge is stimulated to form kidm:y substance is belieYed to be supplied by the urcteral bucl. However, and :\fostofi3 suggPst that perhaps this is crrnneous. In their study of renal agenesis ancl clysgencsis they cite l l examples which imply that the presence of a urctcric bud w,rn not necessary for kidney dewlopnwnt. Thcy believe that the mctanephric blastema lrns within itself the
/Ja./1:inwrc, .711 d .
for kidney differentiation Cn1c11 walcP has shown that the rrnal will form despite the Jack of observation of an lent support to this suggestion. He found tkJ). the left wolffian duct had failed to rench the but that the left renal blastcnrn present and fused with that of thG side. :\Ioreover, additional evidence wms ohtr111wd the same author who chick embryos of :·lo and 56 hours am[ slim\·,·d that despite the lack of ureteric there was formation of the renal bla:,tern,1 m the metanephrio In the course of a tocrn which i.n turn helpful in the establishmcmt of the and .;\fostofi. 3 posed CASE R.Ti;pQRT
l\1rs. H. entered the hospital in labor at term. She had had two Lllt·
test for w,1s course lwd been uneventful. Aft.er :3 hours of norrrrnl labor ~lie· was deiivered low owr a midlirn, to be a shoulder
region
:-! ounce boy. The infant cx1:ep(. normal iu every distention of the left abdorninal the mass. This t11rnor ,v;.-ts
Accepted for publication B. 'Doroshow, L. W. and Congenital unilateral cases and a, review of the 11: A. E.: Congenital absence of one review of liternT,ltre and report of two cases. l\L J., 18: 750. Hl25. .. . 3 Ashley, D. J B. and l\,fostofi, F. K.: Renal J. Urol 83: 211, 1960. and Clinical erology Cmnpbell B. S,wnders Co., 1\!51, p. H:i2. Phil aclelphia: ""''CHCOMO
597
P.: 'I'hP rcbtion of the growing lVHillerian to the Wolffian duct and its· tancc for genesis of malfonnations. Annt. 81: I, 1941. ' Boyden, E . A.: absence of llw kidney, an interpretation on 10 mm. h1rn1:u1 exhibiting uniJat.eral renal ,tgeneoici. Roe., 52: 325, Hl32. 7 Radman, H. M. · due to fetal abclom i & Gynecol .. 19: Jg I nal enlargement. 1\!62.
598
H. M. RADMAN AND A. E. GOLDSTEIN
found to extend beyond the midline toward the right and extended from the costal margin down to the ilium. The mass was smooth, soft, ballottable and appeared to fluctuate. A flat film of the abdomen revealed a soft tissue shadow compatible with the mass described. An excretory urogram showed that no contrast medium appeared in the left kidney area, but that the pelvis, calyces and kidney on the right secreted promptly. A quantity of bicarbonate of soda was administered orally and radiologic examination of the abdomen showed a definite bowel outline in contrast to the shadow in the kidney area on the left. In view of these findings the mass on the left was conjectured to be kidney. A retrograde cystoscopy was not done. When the child was 41 hours of age an operation was performed. Through a left lumbar incision the mass described was easily isolated and found to be a kidney with markedly dilated pelvis and calyces. There was complete obstruction at the ureteropelvic junction, with no evidence of a ureter. A large vein, probably renal, coursed over the pelvis. No renal artery was found; after vein ligation, the whole mass came out of the wound without attachment. The convalescence was uneventful and the child was discharged from the hospital within a week. The subsequent course has proved to be without event and no additional genital or urinary abnormalities were ever discovered. The specimen consisted of a resected left
kidney which measured 12.0 by 9.0 by 7.2 cm.
It was irregular in shape and made up almost entirely of a thin walled cystic structure. The kidney weighed 338.0 gm. Adjacent to the thin cystic portion of the specimen was a narrow reddish-purple band of thickened tissue which represented all that remained of the renal parenchyma. ·when the mass was opened it was found to contain 300 cc dark amber urine. There was a narrow band of renal parenchyma at the upper and lower poles and along the posterior uncut margin of the specimen. DISCUSSION
Whether or not this case represents an additional example to substantiate Ashley and Mostofi3 theories may be questionable; embryonic proof is not possible. The fact that there was definite kidney development without the presence of a ureter can be cited as evidence in favor of a dysgenetic kidney. On the other hand, it might be conjectured that there was lack of ureteral development because of atrophy of this structure in the antenatal period as the result of deficiency or absence of the blood supply. The initiating factor in the formation of this hydronephrotic kidney appeared to arise solely from the metronephric blastema. The necessary drainage was lacking; function could not be established because of the absence of the ureter. Since there are only eleven previously reported cases, it is felt that the addition of this report to the literature is warranted.
l\'ovenlber & Wilkins
A THEOllETlCAL CONSIDERATION OF RENAL DYSC}ENESIS H. MELVI:\J RADJ\IAN
AND
Fr()}n the Department of Obsielr'ics,
ALBERT E. GOLDSTEIN
For Thr: Women
Rec:ently Doroshow ancl Abcshouse 1 presented review of congenital unilateral solitury kidney with a rc:port of 37 cases ancl a survey of the literature. }n their explanation of some of the causes that produce renal agem,sis, they referred to the vrnrk of several iuvestigators. 2 • 8 In substance one of the theories rc1·olved about development de·· of the ureter. According to Campbell;1 derivation of the kidney depends upon three structmes: 1) the 2) the mesonephros and 3) the met:mephros. 'The pronepbros which degenerates the fourth w1:ek is a remnant of the cxcrdor,v in lower vertebrates. It develops independently as 6 to 10 of tubules with a primary excretory duct opening into the coclomic . The mesoncphrns appears just lmfore the pronephros disappears and consists of tubules emptying into the meRonephric duct. Regression occurs in 12 to 14 weeks. During mcsoncphric or true kidney degeneration, the appears. The commonly accepted theory for the cornabsence of the kidney is the: failure of the wolffian duct to off a (:01,rcsponding uretnal bud after the duct has reached the cloaca. The mechanism. by which the rncsoclerm of the lower encl of tlw ncphrogenic ridge is stimulated to form kidm:y substance is belieYed to be supplied by the urcteral bucl. However, and :\fostofi3 suggPst that perhaps this is crrnneous. In their study of renal agenesis ancl clysgencsis they cite l l examples which imply that the presence of a urctcric bud w,rn not necessary for kidney dewlopnwnt. Thcy believe that the mctanephric blastema lrns within itself the
/Ja./1:inwrc, .711 d .
for kidney differentiation Cn1c11 walcP has shown that the rrnal will form despite the Jack of observation of an lent support to this suggestion. He found tkJ). the left wolffian duct had failed to rench the but that the left renal blastcnrn present and fused with that of thG side. :\Ioreover, additional evidence wms ohtr111wd the same author who chick embryos of :·lo and 56 hours am[ slim\·,·d that despite the lack of ureteric there was formation of the renal bla:,tern,1 m the metanephrio In the course of a tocrn which i.n turn helpful in the establishmcmt of the and .;\fostofi. 3 posed CASE R.Ti;pQRT
l\1rs. H. entered the hospital in labor at term. She had had two Lllt·
test for w,1s course lwd been uneventful. Aft.er :3 hours of norrrrnl labor ~lie· was deiivered low owr a midlirn, to be a shoulder
region
:-! ounce boy. The infant cx1:ep(. normal iu every distention of the left abdorninal the mass. This t11rnor ,v;.-ts
Accepted for publication B. 'Doroshow, L. W. and Congenital unilateral cases and a, review of the 11: A. E.: Congenital absence of one review of liternT,ltre and report of two cases. l\L J., 18: 750. Hl25. .. . 3 Ashley, D. J B. and l\,fostofi, F. K.: Renal J. Urol 83: 211, 1960. and Clinical erology Cmnpbell B. S,wnders Co., 1\!51, p. H:i2. Phil aclelphia: ""''CHCOMO
597
P.: 'I'hP rcbtion of the growing lVHillerian to the Wolffian duct and its· tancc for genesis of malfonnations. Annt. 81: I, 1941. ' Boyden, E . A.: absence of llw kidney, an interpretation on 10 mm. h1rn1:u1 exhibiting uniJat.eral renal ,tgeneoici. Roe., 52: 325, Hl32. 7 Radman, H. M. · due to fetal abclom i & Gynecol .. 19: Jg I nal enlargement. 1\!62.
598
H. M. RADMAN AND A. E. GOLDSTEIN
found to extend beyond the midline toward the right and extended from the costal margin down to the ilium. The mass was smooth, soft, ballottable and appeared to fluctuate. A flat film of the abdomen revealed a soft tissue shadow compatible with the mass described. An excretory urogram showed that no contrast medium appeared in the left kidney area, but that the pelvis, calyces and kidney on the right secreted promptly. A quantity of bicarbonate of soda was administered orally and radiologic examination of the abdomen showed a definite bowel outline in contrast to the shadow in the kidney area on the left. In view of these findings the mass on the left was conjectured to be kidney. A retrograde cystoscopy was not done. When the child was 41 hours of age an operation was performed. Through a left lumbar incision the mass described was easily isolated and found to be a kidney with markedly dilated pelvis and calyces. There was complete obstruction at the ureteropelvic junction, with no evidence of a ureter. A large vein, probably renal, coursed over the pelvis. No renal artery was found; after vein ligation, the whole mass came out of the wound without attachment. The convalescence was uneventful and the child was discharged from the hospital within a week. The subsequent course has proved to be without event and no additional genital or urinary abnormalities were ever discovered. The specimen consisted of a resected left
kidney which measured 12.0 by 9.0 by 7.2 cm.
It was irregular in shape and made up almost entirely of a thin walled cystic structure. The kidney weighed 338.0 gm. Adjacent to the thin cystic portion of the specimen was a narrow reddish-purple band of thickened tissue which represented all that remained of the renal parenchyma. ·when the mass was opened it was found to contain 300 cc dark amber urine. There was a narrow band of renal parenchyma at the upper and lower poles and along the posterior uncut margin of the specimen. DISCUSSION
Whether or not this case represents an additional example to substantiate Ashley and Mostofi3 theories may be questionable; embryonic proof is not possible. The fact that there was definite kidney development without the presence of a ureter can be cited as evidence in favor of a dysgenetic kidney. On the other hand, it might be conjectured that there was lack of ureteral development because of atrophy of this structure in the antenatal period as the result of deficiency or absence of the blood supply. The initiating factor in the formation of this hydronephrotic kidney appeared to arise solely from the metronephric blastema. The necessary drainage was lacking; function could not be established because of the absence of the ureter. Since there are only eleven previously reported cases, it is felt that the addition of this report to the literature is warranted.