Aortic body chemodectoma in a cow: clinical, morphopathological, and immunohistochemical study

Abstract

A 3-year-old Holstein cow with a history of severe weakness, dyspnea, pale mucous membranes, increased respiratory rate associated with marked abdominal respiration, severe arrhythmia, and tachycardia was referred to a slaughterhouse by the referring veterinarian due to poor prognosis. After slaughter, a large, firm, white, multilobulated mass about 5 cm in diameter was located at the base of the heart that extended to the right atrium and obliterated partially the right atrial lumen. Microscopically, tumor cells were aligned along and around the capillaries and were discrete, cuboidal to polyhedral cells with little cytoplasm arranged in distinct packets surrounded by thin fibrous septa. The nuclei were round to oval and were placed centrally in the cells. Immunoreactivity for S100 protein was positive multifocally, mostly in the peripherally located sustentacular cells, but NSE and CrA were negative. On the basis of the clinicopathological and immunohistochemical findings, the tumor was diagnosed as aortic body chemodectoma.