Thymic Epithelial Tumor with Heart Metastasis in a Horse

Figure 2

Photomicrographs of the thymic mass with heart metastasis. (a) The neoplastic cells in thymic mass form solid sheets. Scattered Hassall’s corpuscles (*) present in the mass. Pseudorosette formation is evident around blood vessels (arrow) with a tendency to form a palisading basal cell layer. Haematoxylin and eosin. Magnification x100. Inset: Higher magnification of the thymic neoplastic cells with spindle/oval shape nuclei. Magnification $\times$600. (b) Right atrial wall. The metastatic thymic neoplasm (*) invading the right atrial wall. M: Myocardium. F: adventitial connective tissue of entering vessel into the right atrium. A: part of the right atrial chamber. Haematoxylin and eosin. Magnification x20. (c) Thymic neoplasm; cytokeratin immunohistochemical staining of the neoplastic cells. The neoplastic cells have positive cytoplasmic immunohistochemical labeling for pancytokeratin. Avidin-biotin immunoperoxidase—Amino-Ethyl-Carbazol chromogen. Magnification x100.

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