Dubey, Divyanshu

AbstractBackground and purposeParaneoplastic neurological autoimmunity is well described with small‐cell lung cancer, but information is limited for other neuroendocrine neoplasms (NENs).MethodsAdult patients with histopathologically confirmed non‐pulmonary NENs, neurological autoimmunity within 5 years of NEN diagnosis, and neural antibody testing performed at the Mayo Clinic Neuroimmunology Laboratory (January 2008 to March 2023) were retrospectively identified. Control sera were available from patients with NENs without neurological autoimmunity (116).ResultsThirty‐four patients were identified (median age 68 years, range 31–87). The most common primary tumor sites were pancreas (nine), skin (Merkel cell, eight), small bowel/duodenum (seven), and unknown (seven). Five patients received immune checkpoint inhibitor (ICI) therapy before symptom onset; symptoms preceded cancer diagnosis in 62.1% of non‐ICI‐treated patients. The most frequent neurological phenotypes (non‐ICI‐treated) were movement disorders (12; cerebellar ataxia in 10), dysautonomia (six), peripheral neuropathy (eight), encephalitis (four), and neuromuscular junction disorders (four). Neural antibodies were detected in 55.9% of patients studied (most common specificities: P/Q‐type voltage‐gated calcium channel [seven], muscle‐type acetylcholine receptor [three], anti‐neuronal nuclear antibody type 1 [three], and neuronal intermediate filaments [two]), but in only 6.9% of controls. Amongst patients receiving cancer or immunosuppressive therapy, 51.6% had partial or complete recovery. Outcomes were unfavorable in 48.3% (non‐ICI‐treated) and neural autoantibody positivity was associated with poor neurological outcome.DiscussionNeurological autoimmunity associated with non‐pulmonary NENs is often multifocal and can be treatment responsive, underscoring the importance of rapid recognition and early treatment.

AbstractRecent studies have reported the involvement of peripheral nervous system (PNS) in association with MOG‐IgG, including isolated neuropathies. In this retrospective study we characterized the PNS involvement in MOG antibody associated disease (MOGAD). Six out of 215 MOGAD patients had PNS involvement (all polyradiculopathy) that occurred concurrently with a CNS demyelinating episode. We also demonstrated MOG expression in healthy human controls' proximal nerve root. Nine patients with true‐positive MOG‐IgG1 had PNS involvement temporally unrelated to a CNS demyelinating event. All these patients had an alternate etiology of PNS involvement. Isolated peripheral neuropathy is not a feature of MOGAD, but inflammatory nerve root involvement can occur concurrently with CNS demyelinating events.