PROGRESSIVE ETHMOID HEMATOMA - BACKGROUND, CLINICAL SIGNS, AND DIAGNOSIS

Progressive ethmoid hematoma, or ethmoid hematoma, is an uncommon vasc ular anomaly that is peculiar to horses. The disease most often presen ts as a unilateral, hemorrhagic, soft tissue mass originating in the e thmoid labyrinth. The labyrinth has nasal and paranasal sinus componen ts; the hematoma usually involves both components. The disease is rare . but when it occurs is more common in old horses (at least seven year s of age); there is apparently a greater prevalence in the Arabian and Thoroughbred breeds. Males and females are equally affected. The typi cal presenting complaint is epistaxis. The diagnosis is usually based on history, clinical signs, and endoscopic and histologic appearance. Radiographs are useful in assessing the amount of paranasal sinus invo lvement and are particularly helpful if endoscopic evaluation is equiv ocal.