Anatomopathological aspects of malignant chemodectoma in a dog

Abstract

The objective of this case is to report the anatomopathological aspects of a chemodectoma in a dog diagnosed by the Laboratory of Veterinary Pathology (LVP) of the Federal University of Parana (UFPR) in Sector Palotina, Brazil. Chemodectomas are tumors located at the base of the heart, originating from aortic bodies, respiratory chemoreceptors located close to or inside the aortic arch, and/or receptors located in the carotid arteries. A 12-year[1]old male boxer dog, with a history of sudden death and without any previous clinical manifestations, was sent for postmortem examination at the LVP of UFPR, Sector Palotina, Brazil. Macroscopically, a firm mass was observed in the right atrium, with an irregular surface, blackened with multifocal to whitish coalescing areas, involving the pulmonary artery and aorta. When cut, it was smooth, blackened with multiple whitish areas. There was no intraluminal invasion, however, there was a stenosis of the pulmonary and aortic arteries. Microscopically, neuroendocrine neoplastic cells were seen to proliferate. They were well demarcated, highly cellular, with a comprehensive and encapsulated growth, not invading the wall of the atrium, aorta and pulmonary artery. Thus, concluding the diagnosis of malignant chemodectoma due to the presence of neoplastic emboli. Brachycephalic breeds are believed to be more susceptible to developing this type of neoplasm. Thus, chemodectomas may be asymptomatic since they are rare in their malignant form and the diagnosis is often only confirmed through necropsy followed by histopathological analysis.