Tumor occurrence was 25% in patients with anti-mGluR5 autoimmune encephalitis, higher in Western than Chinese patients

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Frontiers in Medicine Published June 5, 2026 Medically reviewed June 5, 2026 DOI ↗ By Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease

Key Takeaway

Note 25% tumor occurrence in anti-mGluR5 encephalitis, higher in Western patients.

This systematic review and analysis evaluated 60 patients with anti-mGluR5 autoimmune encephalitis. The study compared MRI-negative versus MRI-positive groups to assess tumor occurrence and secondary outcomes including cognitive deficits, behavioral and mood disturbances, sleep disturbances, seizures, movement disorders, decreased level of consciousness, and tumor occurrence. The review does not report safety data, adverse events, or follow-up duration.

Tumor occurrence was observed in 25.0% of the total patient population. When analyzing tumor occurrence by region, the frequency was higher in Western than Chinese patients, with rates of 60.0% versus 4.0% respectively. The authors did not report p-values or confidence intervals for these comparisons.

The review acknowledges that the setting was not reported and that follow-up duration was not reported. No specific limitations were listed by the authors, and funding or conflicts of interest were not reported. The practice relevance was not reported in the source text.

Study Details

Study typeMeta analysis

EvidenceLevel 1

PublishedJun 2026

View Original Abstract ↓

BackgroundAnti-metabotropic glutamate receptor 5 (mGluR5) encephalitis is a rare autoimmune neurological disorder with high clinical heterogeneity. The phenotypic spectrum of anti-mGluR5 autoimmune encephalitis (AE) and the relationship between MRI findings and clinical presentations remain to be fully elucidated.MethodsPreviously reported cases were systematically identified through a literature search of PubMed/MEDLINE, Web of Science and Scopus following PRISMA guidelines. Clinical data from eligible cases, including one from our center, were extracted and analyzed. Patients with a predominant encephalitic phenotype were further stratified into MRI-negative and MRI-positive groups, and statistical comparisons were performed.Results60 patients were identified, including 40 patients with a predominant AE phenotype. Among the anti-mGluR5 AE patients, common manifestations included cognitive deficits, behavioral and mood disturbances, sleep disturbances, seizures, movement disorders and decreased level of consciousness (dLOC). Tumors occurred in 25.0% of patients, with a higher frequency in Western than Chinese patients (60.0% vs. 4.0%; p