Case #8:

Clinical Presentation:
A patient with AIDS presents with a chronic headache and fever and a new focal neurologic deficit. CT scan of the brain reveals hypodense lesions in the cerebral cortex. A stereotactic brain biopsy is done.

Clinical Diagnoses(in order of usual consideration):
CNS Toxoplasmosis
CNS Lymphoma
Progressive Multifocal Leukoencephalopathy
Bacterial Brain Abscess
Fungal CNS lesion (Aspergillus, Mucor, Cryptococcus)
CNS Tubercuolosis

Case 8 Image 1 is a histologic section of the brain demonstrating a multi-nucleate giant cell with an adjacent trophozoiite of Acanthamoeba characterized by a central nucleus containing nucleoli.

Discussion:
Microbiologic Diagnosis:
Granulomatous Amoebic Encephalitis
This protozoal infection occurs worldwide. In patients with AIDS, this parasite may disseminate hematogenously from skin or pulmonary lesions. The organisms are found in soil or warm freshwater sources. Direct penetration of trophozoites through skin and mucous membranes or inhalation of cysts transmits this parasite.