Using rituximab (anti-CD20 antibody) in a patient with paraneoplastic pemphigus.

Paraneoplastic pemphaigus (PNP) is a rare autoimmune mucocutaneous blistering disease that is commonly associated with underlying B-cell neoplasms. There is no standard therapy for PNP. Potent immunosuppression has been the only potentially effective treatment in the setting of malignancy because there is no correlation between tumor burden and activity of disease. Two recent case reports have noted the resolution of lesions of PNP after treatment of the underlying CD20+ B-cell lymphomas with rituximab. Rituximab is an anti-CD20 antibody that has had some success in treating proliferative B-cell disorders. We report a case of PNP in the setting of B-cell lymphoma that did not respond to this novel therapy, and discuss rituximab's putative mechanism of action along with the clinical settings in which this novel therapy may prove useful in the treatment of PNP.