Takeaway
A combination of neuroimaging and laboratory characteristics can be used to differentiate paraneoplastic from idiopathic autoimmune encephalitis (AE), and stratify patients by risk of malignancy and their need for strict surveillance.
Why this matters
AE is associated with two main categories of neural autoantibodies: those specific to intracellular antigens (neural intracellular antibodies, NiAb) and those specific to antigens expressed on the plasma membrane (neural surface antibodies, NsAb). NsAb are usually expressed in idiopathic AE, while NiAb are usually expressed in paraneoplastic AE and are less responsive to immunotherapy. However, clinical and imaging criteria for the differentiation of idiopathic and paraneoplastic AE are yet to be established.
Patients presenting with cerebrospinal fluid-restricted oligoclonal band (OCB) or inflammatory lesions of bilateral temporal lobes should be monitored for malignancies, due to the association with paraneoplastic AE.