Ethmoid Hematoma versus Paranasal Sinus Cyst in a Horse

Two horses presented to PHD Veterinary services for the same complaint of "no air moving through one of the horse's nasal passages!" Both horses had a history of mild to moderate nasal discharge that had increased slowly over the past 6 months. On presentation, a simple evaluation of air passing through the nasal cavities revealed that there was NO air moving through the affected side on each horse however, endoscopic exam revealed a unique problem in each horse.

Figure 1

 In Figure 1, a smooth, white soft tissue mass was identified within 2 inches of the opening of the nasal cavity. This soft tissue mass was completely obstructing the nasal passage. In addition, when the scope was passed through the unaffected side, the soft tissue mass was noted to be extending into the naso-pharynx suggesting that the soft tissue mass extended through out the entire nasal passage (Figure 2). In Figure 2, the white wall of tissue noted along the right side of the image is the soft tissue mass as it extends into the naso-pharynx.The soft tissue mass is most likely consistent with a paranasal sinus cyst however surgical removal will be required to confirm the diagnosis. These types of cysts develop in young horses and grow slowly over months and years until a clinical problem develops. Surgical removal provides complete resolution of these types of cysts!!

Figure 2

Figure 3

In the second horse, a large golden-colored soft tissue mass was identified in the region of the nasal passage closest to the naso-pharynx. There was more discharge associated with this soft tissue mass and small areas of hemorrhage were noted. The soft tissue mass was completely obstructing the nasal passage and was originating from the ethmoid turbinate region which most likely classified it as a ethmoid hematoma!! These types of tumors typically present with a complaint of a unilateral bloody nasal discharge for months before they completely obstruct the nasal passage. However, they can be fast growing tumors and require an aggressive approach to eradicate. Treatment may involve either surgical removal or repeated injections of formalin. It has been my experience, having injected several horses for YEARS, that the tumors tend to return with this approach! Hence, I recommend surgical removal when first diagnosed, especially if the tumor is invading the sinus cavity or the naso-pharynx.