Periorbital and orbital swellings
Swellings
related to the supraorbital margin
Dermoid cysts
Dermoid cysts are usually external angular
cysts although they may occur medially (Fig. 36.1). They often cause a bony
depression by their pressure, and may have a dumb-bell extension into the orbit.
They can also erode the orbital plate of the frontal bone, to become attached to
dura, and for this reason it is important to do computerised tomography (CT) of
the area before excision.
Neurofibromatosis
Neurofibromatosis may also produce swellings
above the eye. The diagnosis can usually be confirmed by an examination of the
whole body, as there are often multiple lesions. Proptosis can also result (Fig.
36.2).
Swellings of
the lids
Meibomian cysts
(chalazion)
These are the most common lid swellings (Fig.
36.3). A meibomian cyst is a chronic granulomatous inflammation of
Basal cell
carcinomas (rodent ulcers)
This is the most common malignant tumour of
the eyelids (Fig. 36.4). It is locally malignant, is more common on the lower
lids, and usually starts as a small pimple which ulcerates and has raised edges.
It is easily excised in the early stages, and can be treated with local
radiotherapy if too big to be excised.
Other lid
swellings
These can occur, but are less common. These
include sebaceous cysts, papillomas, keratoacanthosis, cysts of Moll (Fig. 36.5)
(sweat glands) or Zeiss (sebaceous glands) and molluscum contagiosum. When
molluscum contagiosum occurs on the lid margin, they can give rise to a mild
keratoconjunctivitis and should be curetted.
Carcinoma
of the meibomian glands and rhabdomyosarcomas are rare lesions; they need to
be treated radically. Meibomian cysts that recur frequently should be submitted
to biopsy.
Swellings of
the Lacrimal system
Lacrimal sac
mucocele
This occurs from obstruction of the lacrimal duct beyond the sac, and results in a fluctuant swelling, which bulges out just below the medial canthus. It can become infected to give rise to a painful tense swelling (acute dacryocystitis). If untreated it may give rise to a fistula. Treatment is by performing a bypass operation between the lacrimal sac and the nose [a dacryocystorrhinostomy (DCR)].
Watering of the eye can occur due to
eversion of the lower lid (ectropion), which causes loss of contact between the
lower punctum and the tear film, and this must be distinguished from a mucocele.
Lacrimal gland
tumours
Pathologically these resemble parotid turnouts
(Chapter 42). These are swellings of the gland which lie in the upper lateral
aspect of the orbit, and eventually they lead to impairment of ocular movements
and displacement of the globe forwards, downwards and inwards. They can be
pleomorphic adenomas with or without carcinomatous change, carcinomas or
mucoepidermoid tumours.
Orbital
swellings
If these reach any size they result in
displacement of the globe and limitation of movement. A full description of
these is outside the realm of the text, but some of the most common causes
include the following.
• Pseudoproptosis. This results from a large eyeball, as seen in
congenital glaucoma or high myopia.
• Orbital inflammatory conditions result in orbital cellulitis (Fig.
36.6).
• Haemorrhagic lesions occur in the orbit, after trauma or retrobulbar
injections.
• Neoplasia affects the lacrimal gland, the optic nerve, the nasal sinuses and
glioma (neurofibromatosis) (Fig. 36.6), meningioma and osteoma
(Fig. 36.7).
• Dysthyroid exophthalmos (Fig 36.8, Fig.
36.9 and 36.10). Often unrelated to
active thyroid disease .but can start after thyroidectomy and may need urgent
tarsorrhaphy, large doses of steroids or even orbital decompression, if the
eyeball is threatened by exposure. This is most easily done into the nasal
sinuses (Chapter 44). CT and magnetic resonance imaging (MRI) scans are useful
in diagnosis.
• Pseudotumour, or malignant lymphoma.
• Haemangiomas of the orbit (Fig. 36.11).
• Tumour secondaries or
metastases. These
are rare. In children they usually come from neuroblastoma of the adrenal
gland, whereas in adults, the oesophagus, stomach, breast and prostate can be
sites of primary lesions.
Diagnostic
aids
Diagnostic aids include: radiography, tomography, orbital venography,
ultrasonography, CT and MRI.
Treatment
Treatment
is directed
to the cause of the lesion if at all possible, taking care to prevent exposure
of the eye and discomfort from diplopia.