Morphological changes in the nasal cavity of dogs and cats submitted to routine post-mortem examination: a systematic investigation.

Nasal cavity exploration is not a part of conventional necropsy, and systematic studies analysing histopathological changes in the upper respiratory tract of asymptomatic cats and dogs are scarce. This prospective study was carried out to evaluate the nasal cavity of all dogs and cats submitted to necropsy in a Brazilian veterinary anatomic pathology service from January to December 2023. Of 81 animals included (54 dogs and 27 cats), 67 (82.7 %) had one or more histological changes in the nasal cavity. Idiopathic lymphoplasmacytic rhinitis was the most common change in both species (45/67 [67.2 %]) and one dog with severe inflammation had secondary nasal conchae atrophy. In dogs, erosions and ulcers were the second most prevalent change (4/48 [8.3 %]), and two of these were secondary to uraemia. Oronasal fistulae were seen in two dogs (2/48 [4.2 %]). Neutrophilic rhinitis was the second most prevalent change in cats (5/19 [26.3 %]), one case being associated with Candida sp infection. Neoplastic changes were infrequent in both species (5/67 [7.4 %]). Systematically analysing the histological appearance of the nasal mucosa in presumably asymptomatic animals helps enlighten clinicians and pathologists on what to expect in nasal biopsy samples, assisting them in interpretation of the clinical significance of different lesions and improving the diagnosis of nasal cavity conditions of dogs and cats.