An Elderly Case of Paraneoplastic anti-NMDA Receptor Encephalitis Associated with Small-cell Lung Cancer Expressing NR1 Subunits

Yuya Kobayashi; Mitsuto Sato; Michiaki Kinoshita; Masaki Kakizawa; Kayoko Higuchi; Yamada Mitsunori; Minori Kodaira; Yoshiki Sekijima

doi:10.2169/internalmedicine.4860-20

This article has now been updated. Please use the final version.

An Elderly Case of Paraneoplastic anti-NMDA Receptor Encephalitis Associated with Small-cell Lung Cancer Expressing NR1 Subunits

Yuya Kobayashi, Mitsuto Sato, Michiaki Kinoshita, Masaki Kakizawa, Kayoko Higuchi, Yamada Mitsunori, Minori Kodaira, Yoshiki Sekijima

Author information

Yuya Kobayashi
Department of Medicine (Neurology & Rheumatology), Shinshu University School of Medicine, Japan
Mitsuto Sato
Department of Medicine (Neurology & Rheumatology), Shinshu University School of Medicine, Japan
Michiaki Kinoshita
Department of Neurology, Suwa Red Cross Hospital, Japan
Masaki Kakizawa
Department of Neurology, Aizawa Hospital, Japan
Kayoko Higuchi
Department of Pathology, Aizawa Hospital, Japan
Yamada Mitsunori
Department of Brain Disease Research, Shinshu University School of Medicine, Japan
Minori Kodaira
Department of Medicine (Neurology & Rheumatology), Shinshu University School of Medicine, Japan
Yoshiki Sekijima
Department of Medicine (Neurology & Rheumatology), Shinshu University School of Medicine, Japan

Keywords: encephalitis, NMDAR, Anti-N-methyl-D-aspartate receptor, small cell lung cancer, SCLC, paraneoplastic syndrome

JOURNAL OPEN ACCESS Advance online publication

Article ID: 4860-20

DOI https://doi.org/10.2169/internalmedicine.4860-20

The final version of this article is now available: Vol. 59 (2020), No. 18 pp. 2307-2309

Details

Abstract

A 61-year-old Japanese man presented with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. NR1 antibodies were detected in his cerebrospinal fluid. Chest computed tomography revealed lung tumor. The patient was diagnosed with paraneoplastic anti-NMDAR encephalitis associated with lung cancer and treated with two cycles of intravenous high-dose methylprednisolone and one cycle of intravenous immunoglobulin. However, he died one year later without improvement. An autopsy confirmed small-cell lung cancer (SCLC). Immunohistochemistry revealed the expression of NR1 subunits in the tumor cells, suggesting that SCLC may trigger NR1 autoimmunity though the expression of NR1 subunits as onconeural antigens, expanding the phenotypic spectrum of paraneoplastic neurological syndrome associated with SCLC.

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