A patient with AIDS develops severe headaches. A CT scan demonstrates multiple ring-enhancing lesions of the brain. What diagnosis is most likely?
Toxoplasmosis occurs commonly in HIV and is a parasitic infection causing ring-enhancing lesions (but lots of things can cause ring-enhancing lesions). CMV is common as well and typically causes retinitis. Herpes encephalitis can happen frequently too but causes a diffuse encephalitis.