Cervical extradural mast cell tumour in a 2-year-old Irish Sport Horse colt.

A 2-year-old Irish Sport Horse colt developed sudden and severe neurological problems caused by a rare mast cell tumor outside the spinal cord, which led to spinal cord compression and paralysis. Despite treatment attempts, the colt was euthanized, and post-mortem analysis confirmed the diagnosis of a primary extradural mast cell tumor affecting the cervical region.

Case Presentation

• The patient was a 2-year-old Irish Sport Horse colt.
• The colt showed acute onset of severe neurological symptoms that rapidly worsened.
• Upon hospital admission, the colt was found to be recumbent (unable to stand).

Diagnostic Process

• Initial ante-mortem diagnostics, including clinical and neurological exams, did not identify the cause of recumbency.
• Due to lack of clinical improvement after treatment and supportive care, euthanasia was elected.
• Post-mortem examination was performed to determine the underlying cause of the neurological signs.

Pathological Findings

• A cranial cervical extradural mast cell tumor was identified during post-mortem evaluation.
• The tumor was located outside the spinal dura mater, causing compression of the spinal cord.
• Presence of eosinophilic granulomas was noted, which are inflammatory lesions often associated with mast cell tumors.
• Secondary compressive myelopathy was detected, characterized by degeneration of axons in the spinal cord due to tumor pressure.
• No other masses or significant findings were seen, indicating this was likely a primary tumor rather than metastatic disease.

Clinical Significance

• Neoplasia involving the spinal cord in horses is considered rare.
• Mast cell tumors outside the spinal cord causing extradural compression are especially uncommon.
• The large size of horses presents challenges in diagnostics and treatment options, often leading to poor prognosis.
• This case demonstrates the need for awareness of rare spinal neoplasms in young horses presenting with acute neurological signs.

Summary

• This research article reports a rare case of an extradural mast cell tumor in the cervical spine of an Irish Sport Horse colt.
• The clinical presentation and rapid progression highlight the severity of spinal cord compression caused by such tumors.
• The post-mortem diagnosis emphasizes the diagnostic difficulties ante-mortem and the importance of considering neoplasia in horses with unexplained neurological signs.