Nasal polyps (NP), with the exception of Italy, are an uncommon feline disease first described as turbinate fibrous dysplasia and more recently as turbinate inflammatory polyps. Despite the name, histologically they have a prominent vascular component with woven bone as part of the proliferating stroma. The aetiopathogenesis remains obscure.

Nasal CondroMesenchimal Hamartoma (NCMH) is a benign overgrowth of indigenous tissue, involving respiratory mucosa and cartilage, recently and sporadically described in children presenting rhinorrhea, epistaxis and nasal obstruction. Their pathogenesis is unknown.

Aim of the Work

To assess similarities between NCMH in children and NP in cats in order to rename the disease firstly reported in Italy in 1984.

Material and Methods

Signalment, history, radiological, endoscopical and histological findings in four cats diagnosed with nasal polyp were reviewed.

Results

Two female DSH cat, one male DSH cat and one female Sacred Birman; mean age was 17,2 months (6 months-41 months), mean duration of clinical signs was 6 months (10 days-17 months). Clinical signs included tissue protrusion from the nostril (1), epistaxis (3), paroxysmal sneezing (3), stertor (2), open mouth breathing (2), nasal discharge (2), ocular discharge (1). Radiological findings were increased radiodensity and turbinates lysis of the nasal cavity involved. Anterograde rhinoscopy constantly revealed the presence of characteristic grey/bluish cystic growth of tissue within the nasal cavity and atrophy of the surrounding turbinates. Nasal polyp was monolateral in 3 cats and bilateral in one. In one case the polyp extended to the rhinopharynx.

In all cats, histopathology was consistent with changes in the respiratory epithelium from atrophy to normal, loss or preservation of the microcilia, mild to severe infiltration of inflammatory cells, infiltration of the connective tissue by immature spindle cells and deposition of interstitial amorphous matrix with multi-focal areas of cartilage metaplasia. Frequent was the presence of vascular lagoons/cists containing RBC and lined by morphologically normal endothelial cells.

Discussion and Conclusion

After re-evaluation of the previous histological descriptions of NP and due to the anatomical, clinical, histopathological and epidemiological similarities between NCMH in children and the so called "nasal polyp" in cats, the authors suggest to rename the latter disease as Nasal CondroMesenchimal Hamartoma.