We present four patients with vasculitis manifesting with unusual clinical or pathological features, generating surgical problems. Two cases presented with pulmonary hypertension, with investigations and radiological evidence prompting clinical suspicion of pulmonary thrombo-embolic disease. First case, with an antecedant history of Wegener's granulomatosis (WG), demonstrated following "embolectomy", WG involving the large pulmonary elastic arteries. The second case of inoperable "pulmonary thrombo-embolic disease" was subsequently found at limited post mortem to have giant cell arteritis, which affected widespread small peripheral pulmonary arterial vessels. The other two cases were of aortitis occurring in the background of immune-mediated disease, which had been treated with aggressive immunosuppression regimens. The first of these was a case of Cogan's syndrome complicated by descending aortitis, a rarely reported phenomenon, with co-existent acute endocarditis of the aortic valve leaflets. Most cases of endocarditis in this context occur secondary to and in continuity with ascending aortitis. That this case, and a case of ascending aortitis occurring in the context of relapsing polychondritis occurred in the face of aggressive immunosuppression with an apparent clinical response, underscores the need to not accept a clinical picture at face value. This has implications for clinical management, particularly in the follow-up of surgical prosthetic devices such as grafts which may be used in these cases. All four cases emphasise the continued importance of histology and the post-mortem examination in elucidating previously undetected or unsuspected disease.