Hemangiosarcoma in a Free-living Rufous-bellied Thrush (Turdus rufiventris)

Abstract

Background: Hemangiosarcoma is a malignant endothelial cell-derived neoplasm characterized by an intense cellular proliferation organized in a solid or cavernous pattern. Is characterized by intense cell proliferation, and organized in vascular slits, filled with blood, with fast grow and there is a high recurrence rate. This paper reports a case of multiple hemangiosarcoma in a Rufous-bellied Thrush (Turdus rufiventris).Case: A free-living Rufous-bellied Thrush (Turdus rufiventris), was attended at the veterinary hospital of the Federal University of Mato Grosso (UFMT) - Cuiabá, presenting prostration and three masses located in the following regions: left periorbital area, left lateral insertion of the beak and distal portion of the left tibia. The masses were blackened colored with an irregular aspect, and the cut surface was multiple cavity, filled with a blackened gelatinous material. The animal died during the surgical procedure and was sent to necropsy. Additionally, special immunohistochemistry staining was used in the tumors sections, with primary anti-S-100, anti-Von Willebrand Factor, anti-desmin, anti-actin, anti-cytokeratin and anti-vimentin. The three masses have rounded shape, multilobuled surface, deep red to blackened color, with skin adhered base, and, when cut, blackened color with multiple cavities filled with red to blackened gelatinous material and compressing the adjacent structures. Microscopically was observed a pronounced multifocal proliferation of the neoplastic endothelial cells, which are organized forming vessels with single cell layer and filled with red blood cells, giving a cavernous aspect to the section. Around these vessels were neoplastic areas with a more solid pattern with cells with elongated nuclei. The masses were partially surrounded by fibrous connective tissue, forming a pseudo capsule. In the immunohistochemical test, a strong positivity for the anti-actin antibody was founded, moderate positivity for anti-desmin, and weak positivity for anti-S-100 and anti- Von Willebrand. The test with anti-vimentin and for cytokeratin antibody was negative.Discussion: The clinical status of this bird was followed for seven days, but because is a free-living animal there are not much information about the clinical course of the neoplasm. Is known that it’s common that animals affected by the hem­angiosarcoma have an acute clinical course or asymptomatic, culminating in death, usually associated with hypovolemic shock. The three neoplasms gross aspect described here are compatible with hemangiosarcoma. The masses location were not uncommon although there is a predominance in the intra-coelomic area. In microscopic analysis of the three neoplasm, two histological patterns were observed, both with high cellularity: the cavernous pattern, with exuberant proliferation of blood vessels, and the solid pattern, with few vascular formations. The occurrence of both histological patterns is not uncommon, but the cavernous form being the most frequent. The diagnosis confirmation of hemangiosarcoma was performed by immunohistochemical. The Von Willebrand has low reactivity in avian tissue, as well as the desmin, both with an average to low positivity in this case. The anti-vimentin negative marking in this case generally is observed when the hemangiosarcoma has a more solid histological pattern. The anti-actin antibody is positive for the smooth muscle of the blood vessels, and the anti-S-100 mark nervous tissue, however, although both positive, there are no reports about the specificity of this antibodies to birds tissue. In the author’s knowledge, this is the first neoplasm report in a Turdus rufiventris (Rufous-bellied Thrush).Keywords: bird, tumors, tumor sanguine vessel, wild animals.