Paraneoplastic pemphigus with circulating antibodies directed exclusively against the pemphigus vulgaris antigen desmoglein 3

A patient with follicular B-cell lymphoma presented with erythroderma assoc iated with cutaneous and mucosal blisters. Histologic and direct immunofluo rescence analysis of lesional skin showed a typical pattern of paraneoplast ic pemphigus (PNP). Interestingly, indirect immunofluorescence on rat bladd er was negative and immunoblot analysis of the patient's serum on epidermal extracts demonstrated antiepidermal antibodies that only recognized the pe mphigus vulgaris antigen desmoglein 3, with no antibodies directed against the different proteins of the plakin family To our knowledge this has never been reported in the literature. It exemplifies the overlap between pemphi gus vulgaris and PNP and the pathogenic role of antidesmoglein 3 antibodies in PNP. Moreover, it underscores the need to consider clinical, histologic , and immunologic features fur the diagnosis of PNP.