[Ultrastructural aspects of the pathology of the pyeloureteral junction].

Are described some observation on the ultrastructure of the muscular coat in three cases of the ureteropelvic junction pathology; the patients were undergone at ureteropelvic resection. The authors underline the presence of an important damage of smooth muscle cells at the ureteropelvic junction, also at the renal pelvis and the upper third of the ureter. The abnormalities of muscle cells are of various type: some of these could be cause of the altered motility and fibrosis of the ureteropelvic junction, constantly observed in such pathological abnormality.