**6. Histopathological features of HIV associated large vessel vasculopathy**

Large vessel vasculopathy related to HIV is characterised by involvement of all three layers of the vessel wall [5]. There is infiltration of the vasa vasorum, periadventitial vessels and the adventitia by leucocytes. The media demonstrates fibrosis, muscle damage and elastin fragmentation. The intima also is characterised by disrupted internal elastic lamina and calcification.

Intracranial aneurysms due to HIV have been reported in children [5]. Overall histopathological studies have shown similar microscopic characteristics as previously described. Some studies, however, have shown distinct tissue characteristics in arteries of patients with intracranial aneurysms. These include variable absence of internal elastic lamina fragmentation, medial thickening with sub-intimal SMC deposition, presence of viral protein gp41 within the

macrophages of the arterial wall, as well as identification of agents such as varicella zoster virus in the tissue.
