Atypical Lesions in Canine Leishmaniosis: Description of New Cases

Abstract

Pathological characteristics are well described in canine leishmaniosis (CanL). However, atypical lesions that can be confused with other pathologies or trigger unusual clinical signs are sporadically reported. Atypical lesions were observed during routine postmortem examination in three Leishmania-infected dogs and samples were taken for histopathological and immunohistochemical studies. Clinical signs, biochemical parameters, level of antibodies, and parasite detection by PCR were also evaluated. Atypical lesions were found in the peritoneal cavity, liver, and spleen. Splenomegalia and hepatomegalia were observed in all dogs. In addition, multifocal dark to white nodules of variable size were observed in the peritoneal cavity, liver, and spleen of one dog and in the spleen of the other two dogs. One dog presented diffuse irregular whitish lines with a threadlike appearance and another an intense fibrotic depression in the intermediate lobe. Microscopically, an intense granulomatous inflammation with abundant macrophages, a variable number of lymphocytes, and a low to moderate number of parasites was observed. This study represents the first description of granulomatous peritonitis associated with Leishmania in dogs. It also shows atypical macroscopic expression of hepatitis in CanL. In the absence of an adequate clinical history and laboratory analyses, certain lesions observed in CanL could admit alternative diagnoses.

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

“…6,7 By contrast, atypical clinical signs are also described with the presence of lesions in other tissues and organs such as striated musculature, central nervous system, gonads, endocrine glands, as well as mucous areas such as oral cavity. 8,9 Oral cavity lesions caused by the parasite have been considered as an infrequent form of presentation, and sometimes reported as the only clinical sign of the disease. 10 There is not much information available about oral leishmaniosis, a F I G U R E  Presence of multiple oral lesions in the dorsal area of the tongue.…”

“…The most common clinical signs include weight loss, anorexia, skin lesions, lymphadenomegaly, eye injuries, epistaxis, among others 6,7 . By contrast, atypical clinical signs are also described with the presence of lesions in other tissues and organs such as striated musculature, central nervous system, gonads, endocrine glands, as well as mucous areas such as oral cavity 8,9 …”