Diagnosis and treatment of a congenital cervical tracheal diverticulum in an Arabian foal.

Overview

• This study reports the diagnosis and successful surgical treatment of a rare congenital tracheal diverticulum in a newborn Arabian foal.
• The research highlights the diagnostic process and outcomes following excision of the abnormal airway cyst connected to the trachea.

Background

• Tracheal congenital defects: These abnormalities of the trachea are uncommon but can be serious in animals.
• Tracheal diverticula: Represent a type of congenital paratracheal air cyst characterized by an air-filled and cystic structure adjacent to the trachea.
• Prevalence: Such diverticula are mostly found outside the thoracic cavity (extra-thoracic) and are particularly rare in foals.

Case Presentation

• Patient description: A twelve-day-old Arabian colt exhibited a unilateral swelling on the right side of its neck since birth.
• Initial examination: The swelling was examined via percutaneous ultrasound revealing a spheroid mass with mixed air and fluid content.
• Endoscopy: Upper airway endoscopy confirmed that the mass communicated with the tracheal lumen, indicating a connection with the airway.

Diagnostic Imaging

• Computed Tomography (CT) Scan: A contrasted CT scan was performed to better visualize the lesion’s anatomy.
• Findings on CT: Revealed a narrow isthmus starting between the first two tracheal rings, extending caudally, and then expanding into a dilated cavity corresponding to the palpable mass on the neck.
• Role in surgical planning: The detailed CT imaging allowed precise mapping of the diverticulum for complete surgical excision planning.

Treatment

• Surgical intervention: The foal underwent surgery under general anesthesia to completely remove the diverticulum.
• Histopathology results: Examination of the excised mass confirmed it as a congenital tracheal diverticulum lined with pseudostratified columnar epithelium.
• Additional findings: The cavity contained milk-like fluid and had signs of secondary bacterial infection within the wall.

Outcomes

• Postoperative recovery: The foal recovered favorably from surgery without complications.
• Long-term follow-up: Complete resolution of the swelling was observed 40 days after hospital discharge, with minimal scarring visible.

Significance of the Case

• This case provides insight into an uncommon congenital respiratory anomaly in equine neonates.
• The multi-modal diagnostic approach—ultrasound, endoscopy, and CT imaging—proved effective in accurate diagnosis and surgical planning.
• The successful surgical excision with good clinical outcomes demonstrates that appropriate intervention can resolve such rare congenital conditions.
• It emphasizes the importance of thorough imaging and histological confirmation to understand and treat congenital tracheal diverticula in foals.