NMDA receptor encephalitis with cancer of unknown primary origin.
OBJECTIVE
N-methyl-D-aspartate receptor (NMDAR) encephalitis may present as a paraneoplastic syndrome in young women and is often associated with ovarian teratoma.


METHODS
We report 2 male cases of NMDAR encephalitis presenting with metastatic cancer of unknown primary origin.


RESULTS
Both patients showed cognitive dysfunction as well as other neurological symptoms, slow waves on EEG, and NMDAR antibodies in sera and CSF. Symptoms were effectively treated by pulse steroid and intravenous immunoglobulin treatment. The patients developed metastatic small cell neuroendocrine carcinoma of the parotid gland and inguinal metastatic squamous cell cancer shortly after their neurological episodes. Follow-up PET studies showed small cell lung cancer in the first patient while no primary origin could be found in the second patient.


CONCLUSIONS
Our cases imply that NMDAR encephalitis may present with metastatic cancers that display slow progression rates and occur after encephalitis attacks.
Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul - Turkey.
Arzu
A
Çoban
Department of Pathology, Istanbul Faculty of Medicine, Istanbul University, Istanbul - Turkey.
Gökçen
G
Gündoğdu
Department of Neurology, Istanbul Medipol University Medical Research Center, Istanbul - Turkey.
Mürüvvet
M
Poyraz
Department of Pathology, Istanbul Faculty of Medicine, Istanbul University, Istanbul - Turkey.
Gülçin
G
Yegen
Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul - Turkey.
Aslı
A
Demirtaş-Tatlıdede
Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul - Turkey.
Başar
B
Bilgiç
Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul - Turkey.
Hasmet A
HA
Hanagasi
Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul - Turkey.
Erdem
E
Tüzün
Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul - Turkey.
Hakan
H
Gürvit
D060426:Anti-N-Methyl-D-Aspartate Receptor Encephalitis / Q000175:diagnosis* / Q000188:drug therapy / Q000601:surgery; D001323:Autoantibodies / Q000134:cerebrospinal fluid; D001706:Biopsy; D003131:Combined Modality Therapy; D003952:Diagnostic Imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009382:Neoplasms, Unknown Primary / Q000175:diagnosis* / Q000188:drug therapy / Q000601:surgery; D055752:Small Cell Lung Carcinoma / Q000473:pathology; D016896:Treatment Outcome
D001323:Autoantibodies