Tumours of the upper respiratory system in two horses

Abstract

Both the tumours studied were quite large. One involved the ethmoid region and penetrated and almost completely filled the left nasal cavity for a distance of 12 cm. The left frontal sinus was also almost completely filled. The tumour had grown through the cribriform plate and invaded the cranial cavity. The second tumour involved the posterior two thirds of the left nasal cavity, and the left maxillary sinus, and filled both completely. Histologically both tumours were very similar and were diagnosed as epidermoid carcinomata without keratinisation. In one case the postmortem findings indicated that the tumour had probably originated in the ethmoid region. Postmortem and histopathological findings associated with bibliographic data suggested that the second tumour probably originated in the left maxillary sinus. It was not possible to relate the tumour of probable ethmoid origin to the so called enzootic ethmoid tumour seen in cattle and swine in Brazil.