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Bovine myocardial epithelial inclusions
D C Baker1, S P Schmidt, K A Langheinrich
1Department of Pathology, Colorado State University, Ft. Collins.
Insights
This study examined myocardial epithelial masses in cattle hearts using various microscopic and staining techniques. These masses likely represent misplaced endodermal tissue from early development.
Area of Science:
- Veterinary Pathology
- Comparative Pathology
- Histology
Background:
- Myocardial epithelial masses are rare lesions found in animal hearts.
- Understanding their origin and characteristics is crucial for veterinary diagnostics.
Purpose of the Study:
- To characterize the histological, histochemical, and immunohistochemical features of myocardial epithelial masses in cattle.
- To compare these bovine lesions with similar findings in other species.
- To elucidate the potential origin of these myocardial tumors.
Main Methods:
- Light microscopy, histochemistry, immunohistochemistry, and ultrastructural examination were employed.
- Tissues from ten cattle hearts were analyzed, including samples from slaughterhouses and deceased calves.
- Standard staining techniques (PAS, Alcian blue, colloidal iron) and immunohistochemical markers (cytokeratin, vimentin, CEA, desmin) were utilized.
Main Results:
- Bovine myocardial masses were well-circumscribed lesions in the left ventricle, composed of squamous to cuboidal epithelial cells forming tubular/acinar structures.
- Ultrastructural analysis revealed epithelial cells with sparse microvilli, tight junctions, and perinuclear filaments.
- Immunohistochemistry showed positive staining for cytokeratin (all samples), vimentin (3/8), and CEA (3/8), but negative for desmin.
Conclusions:
- The myocardial epithelial tumors in cattle exhibit characteristics consistent with endodermal rests.
- These findings suggest a developmental origin due to misplaced tissue during organogenesis.
- The study contributes to the understanding of rare cardiac lesions in cattle.
Abstract:
Light microscopic, histochemical, immunohistochemical, and ultrastructural methods were used to examine myocardial epithelial masses in the hearts of ten cattle. The tissues consisted of paraffin-embedded or formalin-fixed samples from eight hearts that were being inspected in slaughter houses and from two hearts from calves that died of septicemia. The ages of the cattle ranged from 4 days to 12 years; the breeds were unspecified for all but one Hereford female and the two Holstein calves; and there were three males, four females, and three steers. The masses in these cases were compared with similar appearing lesions found in other animal species. The lesions in the bovine hearts were single to multiple, well circumscribed, found in the left ventricle wall, and composed of squamous to cuboidal epithelial cells that formed tubular, ductular, and acinar structures with lumens that were void or filled with amorphous protein globules. Electron microscopic examination revealed epithelial cells that had sparse apical microvilli, tight apical intercellular junctions, perinuclear bundles of filaments, and rare cilia. Almost half of the bovine epithelial masses (4/9) had occasional diastase-resistant periodic acid-Schiff-positive granules in their cytoplasm, and few had hyaluronidase-resistant alcian blue-positive granules (2/9) or colloidal iron-positive granules (1/9). All myocardial masses had abundant collagen surrounding the tubular and acinar structures, and 2/9 had elastin fibers as well. None of the myocardial masses had Churukian-Schenk or Fontana Masson's silver staining granules in epithelial cells. Immunohistochemically, all bovine myocardial tumors stained positively for cytokeratin (8/8), and occasional masses stained positively for vimentin (3/8) or carcinoembryonic antigen (3/8). None of the masses stained positively for desmin. The myocardial epithelial tumors most likely represent endodermal rests of tissue misplaced during organogenesis.