Fetal obstructive uropathy: Patterns of renal pathology

Fetal obstructive uropathy (FOU) is characterized by obstruction of the ure thra, renal anomalies, ureterovesical dilatation, oligohydramnios, cryptorc hidism, and abdominal muscle wall changes. The main objective of the presen t study was to better understand the relationship between FOU and renal pat hology using a series of 15 male autopsy cases. A total of 11 cases with pa tent anus and 4 with imperforate anus were analyzed. Of the first group, mo st cases showed obstruction at the level of prostatic urethra. Seven cases showed obstruction at the level of the prostatic urethra and histologic stu dy revealed scarring and partial or complete absence of the prostate, while in the remaining four cases the prostate was present. Of the cases with im perforate anus, two showed obstruction at the level of prostatic urethra, o ne showed posterior urethral valves, and one was obstructed at the proximal urethra. In all cases the kidneys showed mixed (dysplastic and cystic) cha nges with no significant differences between the two groups. An inverse cor relation was observed between degree of renal dysplasia and gestational age , whereas the opposite was true for cystic changes. Distal and collecting t ubules were more intensely immunoreactive to the anti-cytokeratin antibody when compared to proximal tubules. Moreover, anti-cytokeratin immunoreactiv ity was more prominent in tubules displaying cystic dilatation. DNR fragmen tation analysis of renal tissue revealed a higher apoptosis of mesenchymal and tubular cells in the FOU cases, compared to gestational aged-matched co ntrols. These results suggest that renal anomalies in FOU might be related to the gestational age at which the injury occurred and to the duration of the obstruction.