Paraneoplastic pemphigus in a dog

This report presents a case of paraneoplastic pemphigus in a 7-year-old female Bouvier. The dog initially showed extensive oral ulcerations that exacerbated upon treatment with trimethoprim-sulfadiazine. Subsequently, the dog developed vesiculobullous and ulcerative lesions on the ear margins, the nose, periocular, and at the nail beds. Due to complete therapy resistance and a deteriorating general condition, the dog was euthanized. During post-mortem examination a thymic lymphoma was found. While an early biopsy of the oral cavity revealed features of erythema multiforme, skin lesions at necropsy were typical of pemphigus vulgaris. Indirect immunofluorescence of patient serum revealed an antikeratinocyte membrane pattern typical for pemphigus. The serum was also positive on bovine bladder epithelium. In a Western blot, autoantibodies to a 210 and a 190 kDa protein were detected.