Paraneoplastic pemphigus: the first case report from Japan.

Paraneoplastic pemphigus is a rare skin disease characterized by painful mucosal ulcerations and polymorphous skin lesions in association with an underlying neoplasm. A 54-year-old Japanese man, who had received chemotherapy and radiation therapy due to a diagnosis of non-Hodgkin's lymphoma, developed marked stomatitis, conjunctivitis and blisters. Histologic examination showed suprabasal cleft formation with acantholysis and keratinocyte necrosis. Direct immunofluorescence revealed the deposition of IgG at the cell surface of the keratinocytes and C3 at the basement membrane zone. Indirect immunofluorescence on normal human skin and rat bladder sections revealed circulating autoantibodies to the cell surface of both keratinocytes and transitional epithelia. Immunoprecipitation disclosed antibodies reactive to the 250-kD, 230-kD, 210-kD and 170-kD proteins. From these results, a diagnosis of paraneoplastic pemphigus was made. This is the first report of paraneoplastic pemphigus from Japan.