Paraneoplastic neurological syndrome: growing spectrum and relevance.

Paraneoplastic neurological syndromes (PNSs) are group of disorders affecting one or multiple parts of the neuroaxis associated with underlying tumors. An antibody or autoantigen-specific cell-mediated immune response against neural antigen expressed in the tumor is the potential etiology for these rare but refractory disorders. In recent years, wide variety of neurological presentations and autoantibodies has been associated with paraneoplastic autoimmunity, leading to formulation of an updated expert consensus PNS diagnostic criteria. Recognition of these phenotypes and use of serological biomarkers may aid neurologists in early diagnosis of PNS cases encountered in the inpatient or outpatient practice. In this review article, we provide an overview of various clinical, radiological, and immunopathological characteristics of PNS. Furthermore, we discuss the updated PNS criteria and increasing recognition of neurological presentations resembling the PNS among patients receiving immune checkpoint inhibitors.