Spontaneous renal allograft rupture. Clinical and pathological patterns.

Rupture of an allografted kidney occurred in five patients 5-17 days after transplantation. In one patient the microscopic pathological changes corresponded with the nodose polyarteritis pattern. In four patients interstitial rejection nephritis with severe haemorrhage and haematoma was found. It is suggested that the bleeding is due to peristatic hyperaemia and defects in the inner elastic membranes. In one case multifocal necrotizing arteriopathy was the main pathogenetic factor.