Rapid development of giant aneurysm at the base of the brain in an 8-year-old boy with perinatal HIV infection.

An 8-year-old boy with perinatal HIV infection developed a large fusiform aneurysm in the circle of Willis two years prior to death which was confirmed by radiological studies. The postmortem examinations revealed a predominantly intimal, proliferative lesion, and partial destruction of the internal elastic lamina in the involved arteries. Within the intima hyperplasia of fibroblasts and smooth muscle cells was observed. No inflammatory alterations, no granulomas and no multinucleated giant cells could be noted in the vascular walls and in the cerebral parenchyma. A small ischemic infarct was present in the left thalamus. Cerebellum, brainstem and medulla showed multiple areas of progressive multifocal leukoencephalopathy (PML). Immunohistochemistry with anti-gp41, a monoclonal antibody against HIV envelope did not exhibit any positive results. These findings implicate that the vascular lesion might be attributed to primary infection of the brain by HIV which led to a defect of elastic lamina and consecutive intimal hyperplasia. A second hypothesis could be based on the effect of extremely high dose AZT therapy avoiding inflammatory reaction after HIV infection.