Inflammatory polyps of the nasal turbinates of cats: an argument for designation as feline mesenchymal nasal hamartoma.

Inflammatory polyps of the nasal turbinates (IPNT) in cats are benign growths that are histologically distinct from feline nasopharyngeal polyps. Most cats with IPNT are presented at less than 1 year of age with sneezing, noisy breathing and epistaxis, but without mucoid or mucopurulent nasal discharge. Histologically, IPNT are characterised by the presence of woven bone as part of the proliferating stroma and erythrocyte-filled spaces. These unique histological features are analogous to nasal hamartomas (NH) of children, specifically chondromesenchymal hamartoma (NCMH) and sinonasal fibro-osseous hamartoma (SFOH), which also result in signs of nasal obstruction, sneezing and epistaxis. In our study, clinical and histopathological features in five cats with IPNT were compared with published descriptions of NH in children. We conclude that the terminology 'feline mesenchymal nasal hamartoma' provides a more accurate description of the disease currently termed IPNT, and has the added advantage of being consistent with its human counterpart.