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

Tracheal congenital defects are infrequent but serious findings in animals. Tracheal diverticula are congenital air-filled cystic lesions, a sub-type of paratracheal air cyst mainly found extra-thoracically in foals. We describe a case in a twelve-day old show Arabian colt with right sided unilateral cervical swelling since birth. Percutaneous ultrasound revealed a heterogeneously air- and fluid-filled spheroid mass, and upper airway endoscopy confirmed luminal communication to the trachea. Contrasted computed tomography showed a narrow isthmus originating between two proximal tracheal rings and coursing caudally before dilating to form the palpable mass, and facilitated detailed surgical planning. The mass was excised completely under general anesthesia. Histopathological examination confirmed a congenital tracheal diverticulum with pseudostratified columnar epithelial walls, milk-like content and secondary intramural bacterial infection. The foal´s recovery post-surgery was favorable, and resolution was complete with minimal scarring 40 days following discharge. This case illustrates appropriate diagnostic approach and intervention in a rare case of congenital disease.