abnormal growth in the nose. Tumours may be malignant or may remain localized and nonrecurrent. The nose is a common site for tumour growth in the upper respiratory tract because it is exposed to external weather conditions, as well as irritants in the air. Some nasal tumours arise from the mucous membrane that lines the nose; others originate in the brain and spread to the nose.

Epithelial papilloma is one of the more common benign nasal tumours. It affects the nasal mucous membrane and is composed of tall column-shaped cells, mucous cells, which have small hairlike structures called cilia. The tumour grows in small nipplelike protrusions. Nasal carcinoma, a malignant growth, also is found in the nasal mucous membrane. Frequently this type of tumour obstructs the nasal and sinus cavities; it can also erode the bone by invasion and rapid growth. Nasopharyngeal carcinoma is a cancer found at the extreme back of the nasal cavity, near the juncture with the throat. It arises commonly in males and spreads rapidly to the lymphatic nodes in the neck. It spreads under the surface mucous membrane without ulceration of the membrane.

Olfactory neuroblastoma is a highly malignant tumour that originates in the olfactory (smell) receptor cells, located in the upper rear portion of the nose. This tumour is one of the few that can generally be obliterated with radiation treatment.