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Atypical cortical presentation of anti-Ri paraneoplastic encephalitis mimicking tumor
1Department of neurology, Chung-ang University Hospital, 102 Heukseok-ro, Dongjak- gu, Seoul, Republic of Korea. seolah920831@gmail.com.
Purpose:
This report expands the known clinical phenotype of anti-Ri (ANNA-2)-associated paraneoplastic syndrome to include isolated neocortical involvement.
Methods And Results:
We report the case of a 54-year-old woman who presented with transient apraxia, confusion, and headache. Brain MRI revealed a tumor-like lesion in the left frontal cortex. Stereotactic brain biopsy showed inflammatory changes without evidence of malignancy. Serum testing was strongly positive for anti-Ri antibodies, and systemic workup identified breast cancer with axillary lymph node metastasis. The patient received breast cancer surgery and chemotherapy alongside high-dose steroid pulse therapy and four weekly doses of rituximab, resulting in marked resolution of the cortical lesion.
Conclusion:
While current PNS-Care diagnostic criteria enabled a definitive diagnosis, further investigation is warranted to elucidate the underlying pathomechanism of cortical involvement in anti-Ri paraneoplastic neurological syndrome.
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