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

## TL;DR

Two dogs with nasal rhinosporidiosis were treated using a diode laser endoscopically, showing potential for this minimally invasive method in managing the infection.

## Contribution

This report introduces endoscopic diode laser treatment as a novel, minimally invasive approach for nasal rhinosporidiosis in dogs.

## Key findings

- Endoscopic laser treatment successfully resolved the infection in one dog.
- The second dog required a second procedure and antifungal drugs due to recurrence.
- Endoscopic debridement is a feasible and less invasive option for treating nasal polyps caused by R. seeberi.

## Abstract

Nasal rhinosporidiosis is a rare infection that affects both people and animals, including dogs, and can cause abnormal tissue growth inside the nose. Although it is more common in warm countries, a few cases have also been reported in Italy. In this case report, we describe a minimally invasive treatment guided by an endoscope in two dogs with clinical signs and diagnostic findings consistent with this nasal infection. In one dog, the treatment completely resolved the disease. In the second dog, the infection returned, requiring an additional procedure to remove the overgrown tissue and medical treatment with antifungal drugs. These results suggest that endoscopic removal of the abnormal tissue using a laser may be a less invasive surgical option for treating this condition.

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.