Primary central nervous system lymphoma in acquired immune deficiency syndrome mimicking toxoplasmosis.

A 37-year-old man, a hepatitis B virus carrier due to mother-to-child transmission, had a medical examination in September 2008 in nearby hospitals due to anorexia and weight loss. He was transported to our hospital because computed tomography (CT) detected intracranial lesions, and he had a positive human immunodeficiency virus (HIV) antibody test. Head computed tomography (CT) revealed multiple hemorrhagic lesions and enhancement effect, suggesting a thin wall. Also, an enhancement effect was present in the ventricle walls and the subarachnoid space. No accumulation was found in the thallium-201 scintigraphy. The enhancement effect of the ventricle walls and the subarachnoid space disappeared after oral administration of pyrimethamine, sulfadiazine, and calcium folinate, contributing to the diagnosis of an abscess and meningitis due to toxoplasma. However, mass lesions did not reduce. A biopsy was performed on 30 October, and the pathological diagnosis was malignant lymphoma. He died from respiratory function deterioration on 8 November. Lymphoma cells were found in ventricle wall tissue and the subarachnoid space at the autopsy. Toxoplasmosis will typically occur as a brain lesion most commonly in acquired immune deficiency syndrome (AIDS), whereas malignant lymphoma commonly manifests as a brain neoplastic lesion. However, differentiating between images of these lesions is difficult, so diagnosis by early biopsy is recommended.