Ureteropelvic junction obstruction: morphological and clinical studios

This study included 27 patients with ureteropelvic (UPJ) obstruction. Both renal parenchyma and the junctional abnormality were examined and correlate d with clinical findings. Renal biopsies were categorized into grades 1-4,. Those with normal or minimal findings (grade I and 2, respectively) had ex cellent renal function as assessed by radionuclide studies. Those with grad e 4 had severe histological abnormalities associated with poor renal functi on. Grade 3 renal changes were seen in patients whose renal function varied greatly and did not correlate with the extent of the limited histological abnormalities. Although there was great variation in the renal biopsies, gl omerulosclerosis was a consistent finding, associated with extracapiliary p roliferation and periodic acid-Schiff-positive material (? Tamm-Horsfall pr otein) in the urinary space of glomeruli in 91% (10/11) of grade 3 or 3 ren al biopsies. No extracapillary proliferation was seen in grade 1 renal biop sies. The UPJ obstruction area was consistently inflamed and markedly thick ened due to varying degrees of perifascicular fibrosis and muscular hypertr ophy. Extensive fibrosis with associated muscular atrophy was the most-seve re change in this spectrum.