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PARANEOPLASTIC PEMPHIGUS
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Paraneoplastic pemphigus (PNP) is an autoimmune bullous disorder associated with an underlying malignancy, usually lymphoproliferative, with non-Hodgkin’s lymphoma, chronic lymphocytic leukemia, and castleman disease representing the most common disorders. It is characterized by painful intractable stomatitis and polymorphous cutaneous eruption, consisting of blisters, erythema multiforme-like or lichenoid lesions. Acantholysis and lichenoid or interface changes are the hallmark histologic features. Direct immunofluorescence may be variable, typically showing immunoglobulin G and complement deposition intercellularly and often granular/linear complement deposition along the basement membrane. Heterogenous serum autoantibodies, aimed at desmogleins 1 and 3 and members of the plakin family can be detected. There is no consistently effective therapy as PNP is quite refractory to immunosuppression. A therapeutic algorithm is still lacking, and therefore the treatment regimen is often deduced from pemphigus vulgaris. Surgery is the modality of choice in cases of operable solid tumors. The literature regarding systemic therapies is still sparse, given the rarity of the disease, consisting mostly of case reports or series and often relies on heterogenous combinations of adjuvant immunosuppressants to allow steroid tapering. Treatment should be individually tailored considering the patients’ clinical presentation and morbidities, and the potential adverse effects of the various regimens. The authors start prednisone at 0.5-1.0 mg/kg/d, usually resulting in cutaneous lesion regression. Rituximab or IVIG is often initiated to relieve recalcitrant stomatitis. See Table 39-1.
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