Bilateral popliteal aneurysms complicating adult polycystic kidney disease in a patient with a marfanoid habitus.

A man born in 1944 presented with an episode of macroscopic haematuria during a urinary tract infection in 1988. He was unusually tall at 2 metres. An intravenous pyelogram and an abdominal ultrasound disclosed the presence of bilaterally enlarged polycystic kidneys and a polycystic liver. There was a family history of renal disease. Plasma creatinine (180 micro mol/l) and blood pressure (150/100 mm Hg) were both raised. Despite good blood pressure control his renal function declined progressively and he started renal dialysis treatment in 1995. He received a renal allograft in 1996. In 1994 he had noticed a painful swelling behind his left knee. Computed tomography with contrast showed a large popliteal aneurysm. This was replaced with a vein graft. The right popliteal artery showed milder changes, and this was repaired in 1999. Popliteal aneurysms develop most often in older vasculopaths with multiple risk factors; connective tissue disorders have rarely been associated with their presence in younger patients. Polycystic kidney disease has been associated with several aneurysms, most notably cerebral, but not popliteal. The patient's marfanoid habitus also may have played a part. This case emphasises the mixed aetiology of popliteal aneurysms.