Cardiac Rhabdomyomatous Dysplasia in a Heifer Essays

Summary This report is about an incidental finding during slaughter inspection of the heart in a heifer from a feedlot. The lesion, studied by histopathology and immunohistochemistry, resulted composed by several types of heart tissues, all of them immature, disordered and, out of proportion. The most conspicuous was a disperse population of large, vacuolated and PAS positive cells, forming islands, enmeshed in excessive fibrous connective tissue. These cells were identified as abnormal Purkinje fiber-like cells, known as spider cells which resulted markedly positive to desmin, and negative for vimentin, smooth muscle ÃŽ ±-actin and myogenin factor 4. Based on characteristic changes and immunoreactivity, the lesion was originally classified†¦show more content†¦Therefore, we sustain the opinion that, in this kind of lesions the common denominator is a congenital dysplasia and propose the term rhabdomyomatous dysplasia for this kind of lesions in the heart. Key words: rhabdomyoma, hamartoma, dysplasia, heart, bovine During the red offal inspection in an abattoir for slaughter bovines, an alteration inside the right free ventricular wall in a heart was recognized. The affected heart belonged to a commercial cross heifer from a feedlot. The heart was condemned and the lesion was trimmed for subsequent examination. Apart from a congested liver that passed inspection, other lesions were not recognized in the carcass. The official veterinarian thought that the heart lesion could be a scar. Two samples fixed by immersion in 10% buffered formalin, were submitted to the pathology lab. The samples were processed routinely, embedded in paraffin, sectioned at 4  µm and stained by HE. Furthermore, special stains such as PAS, Masson trichrome, and Giemsa were carried out. Macroscopically the lesion was whitish to grayish, more obvious from the endocardial side and not well defined at edges. The lesion was rhomboidal with dimensions 4 cm width and 5 cm long. The lesion was smooth on surface, mobile and exte nsible as part of myocardium. The myocardium affected was almost entirely the whole wall, including papillary muscles and