Two Cases of Nasal Rhinosporidiosis in Dogs Treated Endoscopically with a Diode Laser

Nasal rhinosporidiosis is a chronic granulomatous infectious disease that affects the mucous membranes of the nose and nasopharynx in humans and animals. Although it is endemic in tropical and subtropical regions, sporadic cases have been reported worldwide, including a few cases in Italy. The aim of this report is to describe two cases of nasal rhinosporidiosis in dogs from the same geographical region (Northwestern Italy) that were treated using a diode laser under endoscopic guidance. Both dogs presented persistent respiratory signs, including nasal wheezing, sneezing, and unilateral mucous, catarrhal and hemorrhagic discharge. Both dogs underwent diagnostic procedures, including rhinoscopy, which revealed abnormal tissue growth. Histopathological examination confirmed a diagnosis of proliferative-polypoid rhinitis caused by Rhinosporidium seeberi in both cases. In one dog, medical therapy with itraconazole failed to resolve the fungal infection. A local endoscopically guided treatment using a diode laser was thus proposed and successfully performed for polyp removal in both animals. Post-surgical rhinoscopy showed no tissue regrowth in one dog. The second dog experienced recurrence and progression of clinical signs following the first treatment. A second intervention was therefore needed, along with additional oral medical therapy to resolve the fungal rhinopathy. Both dogs were monitored for a minimum follow-up period of one year. Endoscopic debridement is a feasible, minimally invasive technique that could represent a new therapeutic option for the removal of nasal polyps caused by R. seeberi.