Lung cancer masquerading as a paraneoplastic neurologic syndrome without a primary lung mass: Case report and review of literature

• Type of Material: Article
• Authors: Krisha Desai, Emory University; Ankur Aneja, Emory University; Munish Luthra, Emory University
• Language: English
• Date: 2021-11-01
• Publisher: Medknow Publications
• Publication Version: Final Published Version
• Copyright Statement: © 2021 Indian Chest Society
• License: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.4103/lungindia.lungindia_893_20
• Title of Journal or Parent Work: Lung India
• Volume: 38
• Issue: 6
• Start Page: 577
• End Page: 580
• Grant/Funding Information: Nil.
• Keywords: paraneoplastic encephalitis; encephalopathy; Autoimmune encephalitis; small cell lung cancer
• Research Categories: Health Sciences, Oncology; Health Sciences, Immunology

Abstract

Paraneoplastic and autoimmune encephalitis (AIE) syndromes describe a range of inflammatory disorders of the brain. “Classic” paraneoplastic encephalitis syndromes occur due to a remote neoplasm and are associated with antibodies that target intracellular neuronal proteins while the more recently described AIE syndromes are not always paraneoplastic and occur in association with antibodies that target cell-surface neuronal receptors (e.g., anti-NMDA receptor, anti-LGI1, anti-GABAB receptor).[1] Diagnosis can be difficult and delayed due to nonspecific clinical, imaging, and laboratory findings, and in those syndromes associated with a neoplasm, the neurologic syndromes often precede the cancer diagnosis. We present a case of a 64-year-old patient diagnosed with anti-GABAB receptor encephalitis that subsequently revealed an underlying small cell lung cancer without a primary lung tumor. This case highlights the clinical challenge in diagnosing immune-mediated encephalitis, its methodical work up, and subsequent management.