Leishmaniasis in a Cat with a Concurrent Cutaneous Squamous Cell Carcinoma

Abstract

Background: Visceral leishmaniasis is an important zoonosis caused by the protozoan Leishmania infantum and is considered an emerging disease in domestic cats. The clinical manifestation of leishmaniasis in felines is usually associated with the presence of immunosuppressive comorbidities, such as neoplasia. Scarce studies suggest the existence of an association between feline leishmaniasis and cutaneous squamous cell carcinoma (CSCC). Therefore, in order to contribute to a better understanding of the relation between these diseases in domestic cats, the aim of this study was to report a case of leishmaniasis in a cat with a concurrent CSCC from an endemic region for canine visceral leishmaniasis.

Case: A 9-year-old crossbred male cat, with white coat and outdoor access, was evaluated at the Veterinary Hospital of the Federal Rural University of Semi-Arid (UFERSA), located in Mossoró city, Rio Grande do Norte state, Brazil. The animal had a history of a skin lesion in the head, with a time of evolution of 1 year. In the physical evaluation, it was observed an ulcerated lesion (3.8 x 3.6 x 1.0 cm), with raised, irregular, and thickened edges, muscular tissue exposition, and bone adhesion, affecting frontal, temporal, and parietal regions, in the left antimere. Additionally, it was noted bilateral submandibular lymphadenopathy. Complementary exams showed a discrete increase in creatinine levels (1.8 mg/dL) and hyperproteinemia (9.5 g/dL) due to hyperglobulinemia (6.5 g/dL). An immunochromatographic test was performed to detect antibodies against feline immunodeficiency virus and feline leukemia virus antigen, with a negative result. Submandibular lymph node cytology revealed the presence of structures with morphology compatible with amastigote forms of Leishmania spp. The histopathological analysis of the cutaneous ulcer diagnosed a moderately differentiated CSCC. After the conclusion of the diagnosis of feline leishmaniasis and a concurrent CSCC, the animal died before initiating any treatment. It was not possible to perform the necroscopic exam. 

Discussion: Leishmaniasis in cats is reported with a lower frequency compared to the cases of the disease in dogs. The role of cats in leishmaniasis epidemiology is not completely elucidated but is believed that these animals might act as secondary reservoirs for L. infantum, and are not responsible for the persistence of infection in environments where the primary reservoir, which is mainly represented by dogs, are not present. Nevertheless, the case reported was from an endemic region for human and canine leishmaniasis, which probably favored the infection of the animal with the protozoan. Clinically, feline leishmaniasis is characterized by cutaneous lesions, but other clinical signs, such as lymphadenopathy, gingivostomatitis, ocular and respiratory disorders, weight loss, and apathy, can occur. Regarding the clinicopathological findings observed in infected cats, normocytic normochromic anemia, hyperproteinemia, hyperglobulinemia and increased creatinine are commonly reported. A few case reports on feline leishmaniasis were published with animals from Brazil, and the association of this infectious disease with CSCC is rare. It is suggested a synergism between feline leishmaniasis and CSCC and is believed that the neoplasia might have its evolution accelerated by the systemic dissemination of the protozoan and/or the proliferation of the parasite in the skin. In cats with CSCC from endemic regions for human and canine visceral leishmaniasis, the concomitant occurrence of such infectious disease must be investigated.

Keywords: leishmaniasis, infectious disease, cutaneous neoplasia, Felis catus, comorbidities.

Título: Leishmaniose em um gato com carcinoma espinocelular cutâneo

Descritores: leishmaniose, doença infecciosa, neoplasia cutânea, Felis catus, comorbidades.