Paraneoplastic pemphigus mimicking toxic epidermal necrolysis associated with B‐cell lymphoma

clinical response of the lymphoma as partial remission. Currently, he continues to be treated for follicular, CD20-positive NHL by a combination of rituximab and chemotherapy. Our observations on this case indicate that rituximab could be an effective alternative in the treatment of PNP as well as of NHL. In fact, some case reports have documented successful treatment of PNP associated with NHL with rituximab. Rituximab depletes both normal and abnormal CD20-expressing B cells. Consequently, the improvement observed in PNP patients may be due either to the reduction of neoplastic B cells or to a decrease in the abnormal immune response related to the reduction of normal B cells. Additionally, the mechanisms underlying the beneficial results of rituximab therapy beyond B-cell depletion have been also reported. However, there are an almost equal number of cases reported in which rituximab has been unsuccessful in halting progression of PNP. There are several possible explanations for the lack of efficacy of rituximab in these cases. There may be CD20negative plasma cells that continue to produce specific antibodies and/or there may be CD20-negative B-NHL cells also contributing to autoantibody production(5). Accordingly, there are various opinions about the effect of rituximab for PNP. But, for resistant cases to conventional treatment as in this case, rituximab is one of the important therapeutic options.