Paranasal sinus osteoma in an American miniature horse: computed tomographic evaluation and surgical management

A 3-year-old American Miniature Horse stallion was presented with a suspected mass in the right nasal region. The horse experienced nasal discharge from the right nostril and difficulty breathing. Computed tomography revealed a subcutaneous soft tissue swelling visible on the right side of the face. A 3 times 4 cm paranasal sinus osteoma located dorsal and medial to the first molar was surgically removed. The most common location of osteomas in horses is paranasal sinuses. The American Miniature Horse presented in this case is consistent with observations made by others, that sinus osteomas in horses occur almost exclusively in young mate horses. The reason for this tendency is unknown