Lymphangiosarcoma in a horse.

This research article discusses a case of a 15-year-old Dutch Warmblood mare that was diagnosed with lymphangiosarcoma, a rare type of cancer in horses. The diagnosis was confirmed through histopathology, immunohistochemistry, and electron microscopy after the mare was presented with symptoms including respiratory distress and anorexia.

Background of the Study

• The study investigates a rare case of a 15-year-old Dutch Warmblood mare that exhibited symptoms including breathing difficulties and lack of appetite.
• The horse’s condition worsened, leading to the decision to euthanize and perform a necropsy (post-mortem examination) to identify the cause of illness.

Findings

• Upon examination, an abnormally large fluid filled space (liquothorax) was found in the horse’s thoracic cavity, as well as an abdominal mass.
• Further investigation during the necropsy revealed an invasive tumor in the visceral trunk of the horse. This tumor had extended through the diaphragm and into the mediastinum (the central compartment of the thoracic cavity).

Diagnosis and Analysis

• The researchers carried out a histopathological examination, which involves studying the microscopic structure of diseased tissues. This revealed ’empty’ channels lined with atypical (abnormal) endothelial cells (cells that line the interior surface of blood vessels and lymphatic vessels).
• Immunohistochemistry – a process that uses antibodies to detect the presence of specific proteins in cells – was employed to further confirm the nature of the cells. This depicted neoplastic cells (cells that grow and divide more rapidly than normal cells leading to the formation of a tumor) arranged in a chaotic pattern.
• Electron microscopy, which involves the use of a high-powered microscope to view cells at an ultra-structural level, was also used to further examine the cells.
• All these investigations led to the diagnosis of a rare form of cancer known as lymphangiosarcoma. This type of cancer involves the malignancy of the lymphatic vessels.

Significance of the Study

• The study contributes to the body of veterinary pathology literature by describing a rare case of lymphangiosarcoma in a horse. This knowledge can aid in the recognition and understanding of this rare form of cancer in horses.
• It underscores the importance of comprehensive diagnostic methods like histopathology, immunohistochemistry and electron microscopy in making accurate diagnoses.