Diagnosis
Upper airway endoscopy revealed a severe narrowing of the right nasal passage, dynamic nasal collapse observed in the left nostril and mild to moderate thick dark sanguineous discharge was also noted. Computer tomography (CT) was performed under general anesthesia. The gelding was sedated with xylazine (Xylazil 100 0.5 mg/kg bwt i.v.)1 and Butorphanol (Butorgesic 0.1 mg/kg bwt i.v.)1. General anesthesia was induced with ketamine (Ketamil 2.2 mg/kg bwt i.v.)1 and midazolam (Midazolam Alphafarma 0.05 mg/kg bwt i.v.)2 and maintained on isoflurane (Isorane)3 and medical oxygen delivered through a circle breathing system. The examination disclosed a large infiltrative, heterogeneous, and partially hyperattenuating, non-contrast enhancing mass extending throughout most of the right paranasal sinuses (Figure 1 and 2). The mass was effacing the right ethmoid turbinate and was expansile caudally, impinging upon the axial margin of the right orbit. The mass extended dorsally into the rostral aspect of the right frontal sinus and caudoventrally into the rostral aspect of the right sphenopalatine sinus and was causing moderate leftward displacement of the nasal septum with subsequent collapse of the left nasal passages. There was complete obliteration of the right infraorbital canal and nasolacrimal duct at the level of the mass. A lobular soft tissue attenuating structure is present throughout the left sphenopalatine sinus. An emergency tracheostomy was performed during recovery from general anesthesia. A metal 22 mm diameter tracheostomy tube was placed and remained in position until the surgical procedure was completed.