Paraneoplastic Neurological Syndromes: Transitioning Between the Old and the New

Purpose of Review Paraneoplastic neurological syndromes (PNS) are caused by nervous system-targeting aberrant anti-tumoral immune responses. We review the updated criteria for PNS diagnosis, incorporating novel information on clinical phenotypes, neuronal autoantibodies (Nabs), and tumors. The impact of the oncologic use of immune checkpoint inhibitors (ICI) on PNS occurrence is also addressed. Recent Findings Clinical phenotypes and Nabs are redefined as high/intermediate/low risk, following the frequency of cancer association. Nabs, the diagnostic hallmark of PNS, can target intracellular or surface neuronal proteins, with important prognostic and pathogenic implications. Many novel assays have been incorporated into laboratory diagnostics, that is becoming increasingly complex. ICI fight tumors, but favor autoimmunity, thus increasing the incidence of PNS-like disorders. Overcoming the old PNS criteria, the new ones are centered around the presence of tumor. Clinical presentation, Nabs, and tumor findings are translated in diagnostic scores, providing a useful tool for PNS diagnosis and management.

Automated summary

This review discusses the updated criteria for the diagnosis of paraneoplastic neurological syndromes (PNS) and provides new information on clinical phenotypes, neuronal autoantibodies (Nabs), and tumors. It also explores the impact of immune checkpoint inhibitors on the occurrence of PNS-like disorders. Recent findings reveal that Nabs can target intracellular or surface neuronal proteins, with significant prognostic and pathogenic implications.