Proliferative papulo-nodular glossitis due to Leishmania infantum in a dog

Canine leishmaniosis, caused by the protozoan Leishmania infantum, is an endemic vector-borne disease in Europe. From a diagnostic point of view, the disease can sometimes be a real challenge for the clinician, due to the variability of clinical presentations in a sick dog. These clinical signs can be classified, based on the frequency of presentation, in typical and atypical signs. In dogs is common to find different clinical presentations of cutaneous disease and systemic involvement, while clinical presentations in mucosa are not so common. A 6-year-old, entire, male German shepherd crossbred dog was examined for evident nodular lesions on the tongue. The most important laboratory alteration detected was hyperglobulinemia with an increase in the gamma fraction classified as polyclonal gammopathy. High anti-Leishmania antibodies were detected by ELISA. Tongue biopsy samples were obtained from the lesions with the presence of a diffuse inflammatory infiltrate characterised by macrophages and neutrophils with no compatible forms of Leishmania parasites. However, the presence of Leishmania amastigotes was confirmed by specific immunohistochemistry. A good clinical response to the anti-Leishmania based on meglumine antimoniate and allopurinol was observed after meglumine antimoniate administration. This clinical case describes the presentation of proliferative papulo-nodular glossitis in an L. infantum-positive dog as the most evident clinical finding reported.