“…Pemphigus is a group of chronic autoimmune diseases caused by autoantibodies targeting specific desmosomal proteins on the surface of epithelial cells (in pemphigus vulgaris are typically linked to desmoglein-3 and rarely, in 50% of cases, also to desmoglein-1, the latter an exclusive target antigen in pemphigus foliaceus) with subsequent acantholysis and often with intraepithelial blistering [ 57 , 58 ]. Manifestations in the oral cavity are usually severe and frequently represent the first clinical sign of disease, usually appearing as painful and flaccid vesicles mostly of the gingiva, tongue, and palate with rapid evolution into erosion and ulceration, with the classic positivity to the Nikolsky sign ( Figure 6 ) [ 59 , 60 , 61 , 62 ], Histological examination with adjunctive direct immunofluorescence of the tissues is mandatory for the differential diagnosis, along with blood test including BP180 e BP230. A clinical variant defined as Paraneoplastic pemphigus is often associated to a frequently not yet diagnosed neoplasm (mostly NHL, leukemia, multiple myeloma, etc.…”