Paraneoplastic pemphigus: a subset of patients with pemphigus and neoplasia

We reviewed the clinical, histologic, and immunofluorescence features of 20 patients with pemphigus and neoplasia and compared them will a control group of 17 patients with pemphigus without neoplasia. Patients with neoplasia were divided according to clinical, histologic, and immunofluorescence findings into those with paraneoplastic pemphigus syndrome (12 patients) and those with classic pemphigus vulgaris or pemphigus foliaceus with neoplasia (8 patients). The histologic findings in patients with paraneoplastic pemphigus included acantholysis, interface dermatitis, spongiosis, and satellite keratinocyte necrosis. Histologic findings in the 8 patients with classic pemphigus and neoplasia included acantholysis and spongiosis. Direct immunofluorescence in both paraneoplastic pemphigus and pemphigus with neoplasia showed IgG staining of cell‐surface proteins (intercellular substance) and deposition of immunoglobulin at the basement membrane one. Indirect immunofluorescence with rat bladder substrate was used to differentiate paraneoplastic pemphigus from classic pemphigus. Circulating IgG anti‐cell‐surface protein antibodies were detected in 4 patients with paraneoplastic pemphigus syndrome; they were absent in 2 patients with pemphigus and neoplasia. Immunoprecipitation of sera from the 4 patients with epithelial staining showed the complex of bands identified in studies of paraneoplastic pemphigus syndrome. We conclude that paraneoplastic pemphigus syndrome has distinct clinical, histologic, and immunologic features that differentiate it from classic pemphigus with underlying neoplasia.