Equine paranasal sinus cysts: a report of 15 cases.

This research investigates the clinical and radiographic characteristics of 15 cases of equine paranasal sinus cysts. While factors like breed, gender, and side frequency were found to be irrelevant, two distinct age categories for disease manifestation were identified. Common symptoms included nasal obstruction, facial swelling, and nasal discharge. Radiographs showed sinus opacification and, in some cases, thicker sinus bones. Surgical treatment was typically effective, with no evident recurrence in a follow-up period up to six years.

Study Overview

• The study presents the findings from a detailed study of 15 cases of paranasal sinus cysts in horses. The focus of the study was on examining clinical presentations, radiographic changes observed, and the treatment and follow-up results.
• The researchers examined multiple variables such as breed, sex, and side frequency, but no significant trends were observed in these factors. However, the age of onset presented in two distinct categories: cases that onset before one year of age (3 horses), and cases that were older than nine years (10 horses). This may suggest that age plays a significant role in the development of sinus cysts in horses.

Clinical and Radiographic Findings

• The most common clinical signs of sinus cysts were nasal airway obstruction, facial swelling, and nasal discharge, often occurring simultaneously.
• Through radiographs, several observations were made. Sinus opacification was a consistent finding among all the horses. In several cases, the bone surrounding the sinus had thickened. In about half of the cases, increased intra-maxillary sinus pressure was evident through septal displacement. Less frequently observed signs included expansion, free fluid accumulation within the affected sinus, dental distortion and displacement, and mineralisation.

Treatment and Follow-up

• Two horses were put down without treatment. For the remaining 13, surgical exploration was undergone. Of these, one was euthanized at the time of surgery and another five days post-operation.
• In the remaining 11 cases, all accessible parts of the cyst were successfully removed through surgery. Surgeons established drainage to the nasal meati, a structure in the nasal cavity. These horses recovered satisfactorily, displaying no evidence of disease recurrence in follow-up periods ranging from three months to six years.

Origin of Cysts

• On histopathological examination of the cyst walls, a theory was formed suggesting these sinus cysts may originate from episodes of hemorrhage beneath the upper respiratory tract mucosa, similar to ethmoidal haematomas.