62 THE NOSE AND PARANASAL SINUSES development. The external tumour is subcutaneous, firm and elastic to the touch, and it must be distinguished from a dermoid cyst. The intranasal type resembles a small nasal polypus on inspection and it may appear in the nasal vestibule. It is firm to the touch with a probe and does not enlarge when the baby cries, a fact which distinguishes it from an encephalocele. The glioma is composed of neuroglial tissue and astrocytes, and is not malignant. It should be removed completely. Encephalocele. This is a herniation of dura mater which enters the nose through the foramen caecum or through a dehiscence in the cribriform plate of the ethmoid bone. The cyst contains cerebrospinal fluid and occasionally cerebral tissue. It is smooth, freely movable on its stalk, readily compressible and enlarges with crying. In view of its composition it is dangerous to puncture the cyst to determine the nature of its contents in case an intracranial infection results. The removal is a neurosurgical one and the deficiency in the floor of the skull is closed at the same time. Fig. 27. Dennoid of the nose in a child aged 18 months. The sinus opening on the external nose has become infected. Dennoid Cyst. This is an external midline cyst on the dorsum of the nose which contains hair and amorphous material. It may open on to the surface by a small sinus (Fig. 27) through which hair may protrude. This serves to distinguish it from an external glioma. The cyst tends to extend widely beneath or between the nasal bones towards the base of the skull, so that surgical removal may be an extensive procedure which may necessitate plastic reconstruction. BENIGN TUMOURS Rhinophyma. This condition occurs almost entirely in males past middle age in whom it may produce considerable deformity thus causing much distress on account of the disfigurement (Plate HI, 1). It is a hypertrophy of the sebaceous glands of the tip of the nose and produces a marked swelling of the nasal apex which becomes bulbous in appearance. The skin is coarse and pitted and has an oily appearance because of the excessive secretion of sebaceous material. It is red or blue in colour from vascular engorgement. Treatment consists in shaving off the excess tissue to trim the nose to a suitable size after which a skin graft may be applied.