Multicentric B‐cell lymphoma with presumed paraneoplastic generalized cutaneous sclerosis in a dog

Background Reports of dermal sclerosis in dogs include scleroderma or morphea of unknown cause, cicatricial alopecia and congenital/hereditary fibrosis. Clinical Summary A 12‐year‐old, male castrated chihuahua‐mix dog was evaluated for skin lesions of unknown duration. The dog had severe alopecia, skin thickening and marked peripheral lymphadenopathy. Lymph node cytological investigation, immunohistochemical investigation and clonality testing demonstrated an intermediate to large B‐cell lymphoma. The thickened skin had severe collagen deposition, effacing adnexal structures. The dog's lymphoma was treated but the skin lesions remained unchanged. The dog was euthanized. Conclusions and clinical importance To the best of the authors' knowledge, this is the first report of multicentric B‐cell lymphoma in a dog with concurrent diffuse cutaneous sclerosis, similar to a human paraneoplastic reaction.