Paraneoplastic Autoimmune Multiorgan Syndrome: Paraneoplastic Pemphigus Revisited

Abstract

This chapter summarizes current diagnostic criteria and expands on the unique clinical, histological features and pathophysiology of the mucocutaneous disease known as paraneoplastic pemphigus or, by the more encompassing term, paraneoplastic autoimmune multiorgan syndrome (PAMS). PAMS is an autoimmune mucocutaneous eruption that occurs in association with benign or malignant neoplasms. We provide insight and clarification that PAMS represents only one manifestation of the heterogeneous autoimmune syndrome in which patients, in addition to small-airway occlusion, may display a spectrum of at least five clinical variants, i.e., pemphigus-like, pemphigoid-like, erythema multiforme-like, graft-versus-host disease-like, and lichen planus-like. Multiple specific effectors of humoral and cellular autoimmunity mediating epithelial damage have been identified. Mucocutaneous lesions in patients with PAMS occur as a result of both humoral and cell-mediated immune mechanisms. Treatment is difficult and PAMS often does not respond to treatment of the underlying malignancy. An update of the advances in management and overall prognosis of PAMS is provided.