A Case of Toxoplasmic Encephalitis in an HIV-Negative Patient With Multiple Cerebral Infarction-Like Findings in the Early Stages.

Toxoplasmic encephalitis (TE) is an opportunistic infection that typically manifests in immunocompromised individuals, such as those with HIV infection or AIDS. The characteristic imaging finding is a mass-like lesion with ring enhancement. We report a rare case of TE in a patient who was not infected with HIV with atypical imaging features. An 81-year-old woman developed progressive impaired consciousness over several weeks. Initially, the brain MRI revealed multiple lesions resembling cerebral infarctions, which gradually enlarged and increased in number. Subsequently, gadolinium-enhanced MRI showed ring-enhancing mass-like lesions in the pons and left parietal lobe. Blood tests indicated elevated inflammatory markers and a mildly increased Toxoplasma IgG level. Given the progressive course, empiric therapy with trimethoprim-sulfamethoxazole and clindamycin was initiated, leading to marked improvement in consciousness by the fourth day. Toxoplasma DNA was later detected in the blood, confirming the diagnosis of TE.