Excision of a large orbital dermoid cyst.

T. J., a male Ceylon Tamil aged 15, was admitted to the General Hospital, Colombo, on April 29, 1952, on account of a tumour growing within the right orbit. The tumour had been noted when he was one year old and had been growing steadily larger, the sight of the right eye having been impaired for the last 7 years. Examination.-A soft, fluctuant, oval mass bulged forwards under the right upper eyelid and occupied the space between the upper orbital rim and the eyeball (Fig. l). The eyeball was pushed downwards i" below the level of the left eyeball, and the right orbit was wider than the left. There was no proptosis. The movements of the right eyeball were not impaired and there was no squint. On eversion of the upper eyelid, an oval mass could be seen bulging the upper conjunctival fornix. The tumour was not adherent to the eyelid or conjunctiva. No pulsations were detected on palpation. Diagnosis.-The long duration of the tumour classed it as a non-malignant growth and its round, smooth shape and fluctuant consistency suggested that it might be an orbital dermoid. The absence of pulsation in the tumour, and the fact that a radiograph showed no abnormal aperture between the orbit and cranial cavity suggested that the cyst was not a meningocoele. The widening of the right orbit is seen in Fig. 2. The steady enlargement of the tumour, the facial distortion produced by displacement of the eyeball downwards, and the deterioration in the sight of the right eye made removal of the tumour desirable. Its position made damage to the levator palpebrae