Paraneoplastic pemphigus appearing as bullous pemphigoid-like eruption after palliative radiation therapy.

Paraneoplastic pemphigus is a recently described disease in which patients have polymorphous skin lesions suggestive of both erythema multiforme major and pemphigus vulgaris in association with internal neoplasms, especially non-Hodgkin's lymphoma. These patients have characteristic autoantibodies that bind specific epidermal proteins. A Nikolsky-negative bullous pemphigoid-like eruption developed within the radiation therapy field in a 72-year-old man receiving palliative treatment for recurrent large cell lymphoma. The eruption rapidly progressed to a Nikolsky-positive bullous process more typical of pemphigus vulgaris with extensive involvement of respiratory epithelia. Despite aggressive treatment with high-dose corticosteroids and antibiotics, the patient rapidly succumbed. Results of immunofluorescence studies and autopsy findings confirmed the diagnosis of paraneoplastic pemphigus.