Mesrobian H G, Rushton H G, Bulas D
Section of Pediatric Urology, University of North Carolina, Chapel Hill.
J Urol. 1993 Aug;150(2 Pt 2):793-4. doi: 10.1016/s0022-5347(17)35615-x.
Renal agenesis is generally thought to result from a lack of induction of the metanephric blastema by the ureteral bud, which may be secondary to ureteral bud maldevelopment and/or to a problem with the formation of the mesonephric duct. Multicystic dysplasia is thought to result from early ureteral obstruction as evidenced by the high frequency of associated proximal ureteral atresia. The recent obstetrical practice of large scale screening of large numbers of fetuses with sonography has resulted in a significant increase in the detection of this and other genitourinary anomalies. These findings have contributed to our understanding of the natural history of many of these malformations, resulting in ongoing reassessment and refinement of current management modalities. Thus, it is now well established that a significant number of multicystic dysplastic kidneys, initially detected in utero and followed postnatally, involute and disappear with time. We report the unequivocal presence of unilateral multicystic dysplasia detected during maternal sonography in 3 fetuses, which could not be seen on subsequent studies during the fetal or immediate postnatal period. To our knowledge, these cases constitute the first report of complete in utero regression of multicystic kidneys. This novel observation indicates that some cases of unilateral renal agenesis result from in utero regression of multicystic dysplastic kidneys. This phenomenon may explain the presence of an ipsilateral blind ending ureter found in some patients with unilateral renal agenesis. However, this infrequent observation does not explain all cases of renal agenesis. Thus, the etiology of renal agenesis remains multifactorial.
肾缺如一般被认为是由于输尿管芽未能诱导后肾胚基所致，这可能继发于输尿管芽发育异常和/或中肾管形成问题。多囊性发育不良被认为是早期输尿管梗阻的结果，相关近端输尿管闭锁的高发生率证明了这一点。近期通过超声对大量胎儿进行大规模筛查的产科实践，使得此类及其他泌尿生殖系统异常的检出率显著增加。这些发现有助于我们了解许多此类畸形的自然病史，从而不断重新评估和完善当前的治疗方式。因此，现在已经明确，大量最初在子宫内检测到并在出生后进行随访的多囊性发育不良肾，会随着时间的推移逐渐退化并消失。我们报告了3例胎儿在母体超声检查时明确存在单侧多囊性发育不良，而在胎儿期或出生后即刻的后续检查中却未再见到。据我们所知，这些病例构成了多囊肾在子宫内完全退化的首例报告。这一新颖的观察结果表明，一些单侧肾缺如病例是由多囊性发育不良肾在子宫内退化所致。这种现象可能解释了一些单侧肾缺如患者同侧盲端输尿管的存在。然而，这种罕见的观察结果并不能解释所有肾缺如病例。因此，肾缺如的病因仍然是多因素的。
