FIBROUS dysplasia is a peculiar clinical entity, which is of interest to the Otolaryngologist, because at times it involves one of the paranasal sinuses.Fibrous dysplasia of the bone is the name applied by Lichtenstein (1938) to a polyostotic or monostotic condition apparently due to a perverted activity of the specific bone-forming mesenchyme. It is most frequently localized in the femur, tibia, rib, maxilla and mandible. Among the extra-skeletal aspects of the condition, abnormal pigmentation of the skin, premature sexual development in females and signs of hyperthyroidism have been described in very severe conditions. Case Report Mrs. M. aged 25 years was admitted to L.L.R. Hospital (E.N.T. Department), Kanpur, on 6 March 1967 complaining of left-sided headache and excessive lacrimation (left eye) of one year duration and protuberance of left eye ball which was gradually becoming more and more prominent for the last 3 months. There was no history of nasal obstruction, nasal discharge, epistaxis or diplopia. She gave a history of an operation for similar complaints 6 years previously after which she remained symptom free for about 5 years. The previous operation notes were not available, but the reference card recorded fibrous dysplasia left ethmoid. Examination of the patient revealed left-sided proptosis with pushing of eyeball laterally and upwards and there was a scar medial to the inner can thus of left eye. Oedema of the eyelids (left) was present and on pressing over the lacrimal sac, thick discharge came out through lacrimal punctum. There was no swelling visible or palpable over the maxillary sinus or medial to the inner canthus of eye. Anterior rhinoscopy showed the middle meatus to be unobstructed. Posterior rhinoscopy showed the posterior end of middle turbinate oedematous. The lateral wall of nasopharynx (left side) was pushed medially. Ears, throat and larynx were normal. The patient's hearing was normal and central nervous system examination, including fundus examination and field of vision, did not reveal any abnormality. Routine blood and urine examination were normal. X-ray of the paranasal sinuses revealed haziness of both maxillary antra, more marked on the left side and expansion of the medial wall of the left orbit with alternating areas of density and radiolucency (Figs.