Histopathological lesions in 15 cats with leishmaniosis.

Recent research into the prevalence of Leishmania infantum infection in the Mediterranean basin points to the involvement of cats as a reservoir host, but only sporadic cases of feline leishmaniosis have been reported. Feline leishmaniosis presents primarily as cutaneous disease and diagnosis is based on the demonstration of the parasite by skin biopsy. The present report describes the microscopical changes in tissue biopsies from 15 cats with leishmaniosis. The biopsies were derived from the skin, ocular tissue and mucocutaneous junctions. The most common histopathological feature was diffuse granulomatous inflammation with macrophages containing numerous amastigotes. Other patterns included granulomatous perifolliculitis and lichenoid interface dermatitis, where there were fewer parasitized macrophages. The presence of amastigotes was confirmed by immunohistochemistry in each case. The results of the study confirm the value of histopathological and immunohistochemical techniques for the diagnosis of feline leishmaniosis.