INFLAMMATORY PSEUDOTUMOR ASSOCIATED WITH HIV, JCV, AND IMMUNE RECONSTITUTION SYNDROME

A 37-year-old HIV-positive African woman developed severe chronic diarrhea. Her CD4+ T cell count was 25 cells/mm3. Within 1 month of initiation of highly active antiretroviral therapy (HAART) her plasma HIV viral load became undetectable and CD4+ T cell count rose to 96 cells/mm3, and continued to rise over the following months. Two months after the initiation of HAART she developed vertigo, loss of balance, incoordination, slurred speech, and tremor of the neck and limbs. Neurological examination revealed ocular abnormalities, dysarthria, and monotonic speech. She had bilateral limb dysmetria, past-pointing and endpoint tremor, impaired heel-knee-shin testing, head tremor, and a wide based, ataxic gait. Initial brain MRI revealed a confluent, nonenhancing area of signal abnormality predominantly involving the inferior right cerebellar hemisphere and extending to the posterior vermis, right cerebellar peduncle, and inferomedial aspect of the left cerebellar hemisphere. Six months later, MRI revealed progression of the cerebellar lesion, with nodular enhancement along the inferomedial aspect of the right cerebellar hemisphere. The patient remained clinically stable. MRI 8 months later revealed a large cystic ring-enhancing lesion in the location of the previously noted high signal intensity lesions of the cerebellum, with compression of the posterior fourth ventricle (figure, A). Figure MRI and histologic examination of the cerebellum (A) Gadolinium-enhanced T1 FLAIR MR image demonstrating a large cystic ring-enhancing lesion in the context of high signal intensity lesions of the cerebellum. (B) Excisional biopsy of the cerebellum demonstrating bizarre multinucleated giant …