Nasal polyps are polypoial masses arising mainly from the mucous membranes of the nose and paranasal sinuses. They are overgrowths of the mucosa that frequently accompany allergic rhinitis. They are freely moveable and non-tender. Nasal polyps are usually classified into antrochoanal polyps and ethmoidal polyps. Antrochoanal polyps arise from the maxillary sinuses and are much less common, ethmoidal polyps arise from the ethmoidal sinuses. Antrochoanal polyps are usually single and unilateral whereas ethmoidal polyps are multiple and bilateral. Symptoms of polyps include nasal block, sinusitis, anosmia or loss of smell, and secondary infection leading to headache.