Paraneoplastic autoimmune multiorgan syndrome: 20 years after.

The purpose of this review is to provide insight and clarification in the quandary of classification and delineate clinical and histological features and pathophysiology of paraneoplastic pemphigus. This is a paraneoplastic disease of epithelial autoimmunity and adhesion originally described by Dr. Anhalt in 1990. Paraneoplastic pemphigus represents only one manifestation of the heterogeneous autoimmune syndrome in which patients, in addition to small airways occlusion, may display a spectrum of at least five clinical variants of the mucocutaneous disease [i.e. pemphigus-like, pemphigoid-like, erythema multiforme-like, graft-versus-host disease-like, and lichen planus-like, termed paraneoplastic autoimmune multiorgan syndrome (PAMS)]. There is a need for the expanded, inclusive classification of diverse mucocutaneous and respiratory presentations of PAMS. Multiple specific effectors of humoral and cellular autoimmunity mediating epithelial damage have been identified. An update of advances in clinical and basic research on PAMS and in management and overall prognosis of PAMS is provided.