Based on our findings, we recommend (i) thorough follow-up and close screening for classical Hodgkin lymphoma after detection of anti-mGluR5 encephalitis, (ii) searching for mGluR5 expression in classical Hodgkin lymphoma biopsy material of patients with autoimmune encephalitis, and (iii) inclusion of mGluR5 screening alongside the standard diagnostic procedure for classical Hodgkin lymphoma as this could provide further information on tumor progression and may serve as a prognostic marker. The gene discussed is GRM5; the disease is encephalitis.