Mesothelioma in horses.

This research article discusses the diagnosis of pleural and pericardial mesothelioma in two horses, including its symptoms, cellular characteristics, and the ancillary tests needed to confirm diagnosis.

Clinical Signs and Symptoms

• The article discusses how the horses that suffered from pleural and pericardial mesothelioma showed signs of respiratory distress, a state of depression and pleural pain.
• The body cavities of the affected horses contained a large quantity of serous effusions, demonstrating a severe response to the disease.

Cellular Characteristics

• The researchers conducted a microscopic examination of the effusions and found very large neoplastic mesothelial cells.
• These cells attached to the diseased area had hyperchromic nuclei, meaning they were presenting excessive pigmentation, and densely-staining cytoplasm.
• The cells showed prominent, often multiple, nucleoli—structures residing within the nucleus of the cell that are important for protein synthesis.
• Ultrastructurally, the cancerous cells appeared as solid aggregates with extensive microvillous borders and neolumen formation— indicating an abnormal cell growth pattern.

Diagnostic Processes

• Cytological examination, which is the analysis of cell samples at a microscopic level, was used as an initial diagnostic method for the disease.
• To confirm the diagnosis, the study mentions the usage of ancillary diagnostic tests including electron microscopy and immunocytochemistry.
• Electron microscopy allows researchers to view the ultrastructure of the cells, helping them identify the abnormal growth patterns.
• Immunocytochemistry is a method where antibodies that bind to specific proteins within the cell are used, allowing for the visualization and location of the proteins, typically to identify abnormal cells or cell groups.

Conclusion

• The study indicates the importance of these diagnostic tests to confirm an ante-mortem (before death) diagnosis of mesothelioma in horses.
• By recognizing these clinical signs and utilizing the mentioned diagnostic techniques, veterinarians may be able to detect and treat mesothelioma earlier, potentially saving the lives of affected horses.