Successful treatment of paraneoplastic pemphigus associated with Castleman's disease using membrane therapeutic plasma exchange: A case report.

Paraneoplastic pemphigus (PNP) is a rare autoimmune blistering disease. We report a case in which membrane therapeutic plasma exchange (mTPE) effectively improved oral lesions in a patient with unicentric Castleman's disease(UCD)-associated PNP characterized by elevated anti-desmoglein-3 antibodies. As the lesions persisted despite multiple immunosuppressive therapies and tumor resection, mTPE was introduced to eliminate circulating autoantibodies. Plasma was replaced with 5% human albumin equivalent to about 1.1 times the estimated plasma volume. Two courses of mTPE were performed, each comprising three sessions spaced 1-3 days apart. Following treatment, serum IgG levels declined markedly, with notable healing of oral mucosal lesions and improvement in appetite and quality of life. The treatment was well-tolerated and free of complications. This case highlights the safety and potential clinical efficacy of mTPE and underscores the dual importance of antibody removal and symptomatic improvement in refractory PNP.).