Histological and immunohistochemical insights into pelviureteric junction obstruction in children: A case-control study

Objectives: The pelviureteric junction (PUJ) is a critical anatomical structure regulating urinary flow. In children with hydronephrosis, abnormalities in the PUJ are frequently implicated. Although pyeloplasty has been established as an effective treatment, the exact pathophysiology of congenital PUJ obstruction remains inconclusive. We hypothesize that an alteration in the density of interstitial cells of Cajal (ICCs) and reduced or disorganized innervation may contribute to dysmotility and PUJ obstruction. The main objective was to study the expression of immunohistochemical markers CD117 and S100 in surgically resected PUJ specimens. Materials and Methods: The study investigated PUJ tissues from 40 patients with confirmed hydronephrosis and compared them with age-matched controls. Immunohistochemical markers for smooth muscle cells (CD117) and neural elements (e.g., S100) were used. Morphometric analysis quantified structural changes in the smooth muscle and extracellular matrix. Statistical analysis: Pearson’s Chi-square test was used to conclude the association between the categorical variables. A two-tailed P < 0.05 was considered statistically significant. Results: Compared with controls, PUJ-obstruction cases showed markedly fewer S100-positive nerve fibers (mean 4.05 ± 1.7 vs. 8.15 ± 2.3 per high-power field (HPF); p = 0.001) and reduced CD117-positive ICCs (mean 0.68 ± 0.9 vs. 4.25 ± 1.8 per HPF; P = 0.003), accompanied by a disorganized smooth-muscle architecture. Conclusions: This study demonstrates that there are significant differences in the expression of S100 and CD117 between the case and control groups, with both markers showing reduced expression in the case group. These findings suggest that the pathophysiology of PUJ obstruction cases might involve neuromuscular damage along with a decrease in ICC population.