Clinical and histological characterization of 19 chondro-osseous respiratory epithelial adenomatoid hamartomas and 2 respiratory epithelial adenomatoid hamartomas in dogs.

Nasal biopsies from 21 dogs diagnosed with chondro-osseous respiratory epithelial adenomatoid hamartomas or respiratory epithelial adenomatoid hamartomas were reviewed. Associated lesions included angiomatous tissue (4/21), seromucinous gland proliferation (2/21), and polyps (3/21), and all had chronic inflammation. Dogs had epistaxis (14/21), sneezing (9/21), decreased airflow (8/21), congestion (6/21), and discharge (5/21). In addition to a mass lesion, computed tomography findings ( = 19) included turbinate lysis (10/19), cribriform plate and orbit erosion (4/19), and contralateral extension (8/19). In 16 dogs with outcome data collected 0-49 months after diagnosis, 13 had continued respiratory symptoms, 11 of which received medical management; 2 of the 3 dogs with improvement had radiotherapy/radiofrequency procedures after biopsy. Eight dogs were alive, 5 were euthanized due to the hamartoma (median survival 9.3 months), 2 died from unknown causes, and 1 died from a seizure. Nasal hamartomas are often locally destructive mass lesions that cause recurrent upper respiratory symptoms and may require more aggressive therapeutic interventions for disease control. Diagnosing nasal hamartomas requires integrating the clinical history, imaging results, adequate biopsy sampling of the mass, and the presence of characteristic histologic features.