Surgical Debulking and TransEndoscopic Noncontact Diode Laser Application for Treating a Sinonasal Myxoma in a Horse.

This research discusses the diagnosis and surgical treatment of a quite rare condition called equine sinonasal myxoma, a type of benign tumor in a horse. The research further explains the successful use of surgical intervention and transendoscopic diode laser to treat this condition with no recurrence of the disease for at least 14 months after the surgery.

Background of the Case

• A 5-year-old Murgese gelding horse exhibited symptoms like mild serous nasal discharge, slight facial swelling, reduced airflow from the right nostril, and dull sinus percussion.
• Diagnostic imaging, which included endoscopy, indicated a pale mass in the caudal portion of the horse’s right middle meatus.
• The growth had developed inside the right conchofrontal sinus and nasal cavity, causing a deviation in the nasal septum to the left side.

Surgical and Laser Treatment

• A large frontonasal bone flap was formed while the horse was under general anesthesia. The primary intention was to eliminate the lesion and conduct further diagnostic investigations.
• The mass resembled a small orange in shape. The caudodorsal and rostral parts of the mass had a hard wall while the ventral part was friable. The inner part was hollow, filled with a clear, viscous liquid.
• While surgical excision extensively removed the mass, it was not entirely. Thus, a post-surgery diode laser irradiation and photoablation treatment was implemented to deal with the small leftover lesions in the horse’s nasal cavity.

Pathological Findings and Outcome

• Microscopic assessment showed the mass was made up of spindle-shaped cells, loosely arranged within an abundant, light blue myxoid matrix.
• Based on clinical and pathological findings, the mass was diagnosed as sinonasal myxoma. This type of tumor is benign and grows slowly, but it typically infiltrates nearby tissues, making recurrence after surgical removal highly likely.
• In this particular case, however, combining surgical excision with transendoscopic diode laser irradiation and photoablation resulted in a positive outcome, and no recurrence was noted at least 14 months post-surgery.