Cystic adventitial disease: a trap for the unwary.

Cystic adventitial disease is an uncommon condition. A case of cystic adventitial disease of the popliteal artery is reported in a young man who has been followed up for 14 years after surgical treatment. Early recognition and treatment of the condition will prevent progression to popliteal thrombosis and critical ischaemia. However, diagnosis of the condition is difficult. Characteristic features in the presenting history, such as fluctuation in severity of symptoms, sudden onset after vigorous activity and delayed recovery time after cessation of exercise are identified, which should help the clinician avoid misdiagnosis and delayed diagnosis of the condition. The clinician is also warned of the associated misleading clinical features such as the presence of normal peripheral pulses and normal ankle pressures in some cases of CAD.