Abstract Details

Title A Case of Thymoma-associated Paraneoplastic Encephalitis with Identification of a Novel Neuronal Antibody

Topic Autoimmune Neurology

Presentation(s) P6 - Poster Session 6 (8:00 AM-9:00 AM)

Poster/Presentation
Number 14-001

Objective A healthy adult male presenting with classic autoimmune encephalitis led to discovery of thymoma, with identification of novel neuronal antibody in cerebrospinal fluid (CSF).

Background A 44-year-old male presented with subacute onset of vertigo, headaches, subtle personality changes, short-term memory deficits, and an 11 pound weight loss. He had two unprovoked seizures that were preceded by aura of left tongue and arm paresthesias, and a fixed delusion described as feeling a “string” on his left hand and tongue which he continuously attempted to remove. Physical exam, MRI, and EEG were normal. Laboratory evaluation was notable for hyponatremia and CSF with elevated protein and pleocytosis.

Design/Methods NA

Results Due to suspicion for autoimmune encephalitis a CT chest/abdomen/pelvis was obtained, identifying a 5.3 cm pericardial mass abutting the mainstem pulmonary artery. Biopsy confirmed thymoma. He became increasingly psychotic and disoriented, with persistent symptoms involving left face and hand. Despite negative EEG, these were treated as focal seizures and resolved. His other symptoms (insomnia, psychosis, and hyponatremia) were resistant to treatment. He received IVIg and high-dose steroids. Due to the complexity of thymoma location, neoadjuvant chemotherapy was recommended. He was treated with cisplatin, doxorubicin, and cyclophosphamide coinciding with a second course of IVIg and high-dose steroids, after which his neurologic status slowly normalized over days. Eventually, his serum ACh-binding Ab was positive, as was striated muscle Ab IgG, with titer 1:1280. Autoimmune panels of serum and CSF sent to Mayo Clinic identified cross-reactivity with neurochondrin, indicating a novel neuronal antibody pending further investigation. He completed neoadjuvant chemotherapy and surgical planning for thymoma resection is underway.

Conclusions Patients with subacute onset of neurological decline may need evaluation for autoimmune encephalitis and paraneoplastic syndromes. With ongoing rapid expansion of antibody detection capabilities, it's important to describe phenotype-specific presentations of paraneoplastic encephalitis that may aid early detection of malignancy.

Authors/Disclosures
Alexa L. Carreras, MD PRESENTER	Dr. Carreras has nothing to disclose.
Martha E. Orozco Cortes, MD	Dr. Orozco Cortes has nothing to disclose.
Megan N. Thomas, MD (Barrow Neurological Institute)	Dr. Thomas has nothing to disclose.
Michael V. Robers, MD (Barrow Neurological Institute)	Dr. Robers has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Genentech. Dr. Robers has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for TG therapeutics. Dr. Robers has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Sanofi. Dr. Robers has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for TG Therapeutics. The institution of Dr. Robers has received research support from Bristol Myers Squibb Foundation.
Justin Hoskin, MD (Barrow Neurological Institute)	Dr. Hoskin has nothing to disclose.

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