Bottom line: Glioblastoma may occur at a higher rate in patients with HIV infection, but its incidence remains quite rare.
Summary: Annual incidence of glioblastoma multiforme in the US is 3 per 100,000 persons with about 60% of cases occuring in patients age 55-74 (DynaMed). A PubMed search failed to identify similar incidence data for the population with HIV infection.
Hall JR, et al. Management of glioblastoma multiforme in HIV patients: a case series and review of published studies. Clin Oncol (R Coll Radiol). 2009 Oct;21(8):591-7. doi: 10.1016/j.clon.2009.04.006.
A review of the literature identified 21 cases of glioblastoma multiforme in HIV-postive patients, the median age at presentation was 38 years (range 19-60.) This paper references a study of HIV-positive patients treated at one institution over a 12-year period. The incidence of glioblastoma in this population (N=1,384) was 45 times the incidence in the general population. Neurology. 1999 May 12;52(8):1648-51.