Segmental renal dysplasia associated with ectopic ureteroceles in childhood

Bilateral intravesical ureterocele associated with unilateral partial duplication of the ureter and other anomalies: proposal of a new variant to the classification of ureterocles based on a perinatal autopsy, review of the literature and embryology

The aims of this study were to demonstrate a case of bilateral intravesical ureterocele associated with megacystis and mega-ureters, unilateral partial duplication of the ureter and unilateral segmental renal dysplasia of the upper pole and an accessory spleen and to propose an addition of the new variant to the classification of ureteroceles. A perinatal necropsy was conducted on the 21-week fetus by employing the Rokitansky procedure with evisceration performed in blocks. The autopsy revealed the aforementioned abnormalities without cardiac or neural anomalies. The amniocentesis report was normal. Ureterocele is a saccular expansion of the distal ureter. It is most commonly observed in females and children and usually affects the upper moiety of a complete pyeloureteral duplication. Four types of ureteroceles are described: (A) ureterocele with single ureter (10%); (B) ureterocele with total duplication and intravesical development (10%); (C) ureterocele with total duplication and extravesical development (62%); and (D) ureterocele with ectopic ureter (3%). One case in a new born with bilateral intravesical ureterocele associated with hydrouretero-nephrosis and hyperechogenic spots in kidneys has been reported, but bilateral intravesical ureterocele with unilateral incomplete pyeloureteral duplication has never been described in the literature.

How they begin and how they end: classic and new theories for the development and deterioration of congenital anomalies of the kidney and urinary tract, CAKUT

CAKUT are problems that often require surgical intervention or, in the worst case, lead to renal failure and the need for dialysis and/or renal transplantation. It is believed that these anomalies share a common genetic cause and to date there has been no good animal model with which to study these abnormalities. Although the abnormal interaction between the ureteral bud and metanephric blastema leads to renal hypodysplasia, vesicoureteral reflux, and ectopic ureters to name a few, the genetic and biochemical modulation of urinary tract development is not understood. Studies using the mouse strain mutant for angiotensin type 2 (AT2) receptors have given new insight into this mystery. The animals show defective apoptosis of undifferentiated mesenchymal cells in the area surrounding the developing kidney and urinary tract. This abnormal apoptosis may well interfere with the normal interaction between the ureteral bud and metanephric blastema resulting in CAKUT. This abnormal interaction would theoretically lead to preexisting intrinsic abnormalities of the kidney, which are programmed and take effect early in embryonic development. In the worst cases, the renal abnormalities would lead to progressive deterioration of renal function. Undoubtedly, there are more genes and biochemical modulators involved in this process other than the RAS and AT2 receptors. Our current animal model gives new and unique possibilities with which to study development of the kidney and urinary tract and ultimately seek ways of preventing an often debilitating disease process.

Morphogenesis of nephropathy with partial ureteral obstruction and vesicoureteral reflux

Hydronephrotic kidneys associated with partial ureteral obstruction and vesicoureteral reflux are similar and should exhibit similar morphology if the hydronephrosis was caused by abnormal urodynamic effects or back pressure. Kidneys with partial obstruction were compared quantitatively and statistically to kidneys with reflux to identify the macroscopic and microscopic structures that would indicate similar or dissimilar etiologies of the hydronephrosis. With partial ureteral obstruction the kidneys exhibited a generalized paucity of parenchyma, occurring in the cortex and medulla, and increasing with the degrees of hydronephrosis. Kidneys with reflux, and mild and similar grades of hydronephrosis compared to those of the obstructive forms were indistinguishable microscopically. Kidneys with reflux and more severe grades of hydronephrosis were different in that the cortex and medulla exhibited hypoplasia combined with dysplasia and, although the cortex was approximately equal in thickness, the glomerular counts were smaller. These features in kidneys with reflux were proportional to the degree of lateral ectopia of the corresponding ureteral orifice. Obstructive atrophy of renal parenchyma explains the morphology of the obstructive hydronephrosis, whereas the hypoplasia and dysplasia corresponding with orifice position in the kidneys with reflux are explained more readily by the bud theory, in which the ureteral bud, metanephric mesenchyme and induction capabilities of each are all at fault. In the absence of infection the kidneys may undergo progressive atrophy with partial obstruction of the ureter, whereas the kidneys with reflux exhibit performed grades of hydronephropathy, which are determined embryologically.

Reduction in renal size associated with complete ureteric duplication

Ureteric duplication, whether complicated or not, is usually associated with an increased in renal length. Two cases of renal duplex with nonfunction of the upper moeity, exhibiting a reduction in renal size, are presented. The radiologic features and the cause of this reduction in size are discussed. The importance of the postmicturition radiographs in cases of urinary tract infection is stressed.

Ectopic ureterocele, hydroureter, and renal dysplasia: an embryogenic triad

A review of the literature of the embryogenesis of ectopic ureterocele is presented. A theory linking the triad of ectopic ureterocele, hydroureter, and renal dysplasia to a primary intrinsic developmental abnormality of size and position of the ureteral bud is postulated.