Ethmoid hematoma of the equine.

Two cases of ethmoid hematoma of the equine are reported. Clinically both horses had intermittent unilateral epistaxis unassociated with exercise. In one horse, diagnosis was based on the use of an endoscope for visualization and for biopsy of a mass associated with the ethmoid turbinates. In the other horse, exploratory trephination of the posterior maxillary sinus was necessary to obtain a diagnostic biopsy specimen. Radiography was helpful in the diagnosis of one case. Surgical removal of the mass was attempted in one case. Histological examination of the biopsies was the single most definitive diagnostic technique in both cases.