Abnormal neurons in teratomas in NMDAR encephalitis

Area of Science:

• Neuroimmunology
• Gynecologic Pathology
• Oncology

Background:

• Ovarian teratomas are frequently associated with N-methyl-d-aspartate receptor (NMDAR) encephalitis.
• However, the specific pathological features of teratomas in NMDAR encephalitis patients remain underexplored.
• Understanding these features could improve management of autoimmune encephalitis and teratoma-associated diseases.

Purpose of the Study:

• To characterize the unique neuroglial organization within ovarian teratomas from NMDAR encephalitis patients.
• To identify pathological differences between teratomas associated with NMDAR encephalitis and control teratomas.

Main Methods:

• A case-control study compared ovarian teratomas from 5 NMDAR encephalitis patients with 38 controls.
• Histopathological and immunological stains examined teratomas for central nervous system (CNS) tissue and inflammatory infiltrates.
• Key outcome measures included the frequency of atypical CNS neuronal elements and their relationship with immune infiltrates.

Main Results:

• Atypical neurons, resembling gangliogliomas or ganglioneuroblastoma, were found in 4 of 5 teratomas from NMDAR encephalitis cases, but not in controls (P < .001).
• Abnormal neuroglial elements were closely associated with immune infiltrates in teratomas from NMDAR encephalitis cases (4/4).
• Inflammatory infiltrates were not associated with neuroglial tissue in control teratomas (P < .001).

Conclusions:

• The presence of abnormal neurons within ovarian teratomas reliably distinguishes NMDAR encephalitis cases.
• These abnormal neuroglial elements may play a role in triggering autoimmunity in NMDAR encephalitis.
• Findings highlight the importance of pathological examination of teratomas in autoimmune encephalitis.