The patient went on to have a biopsy. 

Histology

MICROSCOPIC DESCRIPTION: Paraffin sections show fragments of cerebral cortex and white matter. Within the white matter there is aggregation of lymphocytes and plasma cells with foci of necrosis containing acute inflammatory and necrotic debris. Scattered small aggregates of degenerate organisms with features strongly suggestive of tachyzoites of Toxoplasma are noted. The adjacent white matter and cortex is edematous and shows foci of active cerebritis. No evidence of tumor is seen.

FINAL DIAGNOSIS: Cerebral toxoplasmosis.

Serology

Toxoplasma IgG Antibody: DETECTED