The orbit may be infiltrated by malignant tumours arising in the globe or in any of the surrounding structures, such as the eyelids and paranasal sinuses. If there is extensive orbital involvement, it may be necessary for orbital exenteration as part of the surgical rehabilitation.
Tumours originating in the lids, particularly meibomian gland carcinoma and neglected basal cell or squamous carcinomas, can spread c
Figure 13.9 (a) Fungating melanoma in young patient with terminal disease, (b) the periosteum is incised outside the orbital rim, separated from the orbital walls, the orbital contents are removed leaving a 7-10mm stump at the orbital apex, to prevent CSF leakage, (c) with skin-sparing exenteration there is a rapid healing and retraction of the skin over a few weeks after surgery; (d) where the eyelid skin has been excised, the socket can either be left to heal by granulation, or else grafted with split-thickness skin.
posteriorly through the septal connective tissue to enter the orbit. Diplopia on extreme gaze is an important early sign suggesting orbital invasion and fixation of the mass to the underlying bone suggests more advanced disease.
Perineural invasion, usually along branches of the frontal nerve and liable to cause pain, is commonest with squamous cell carcinoma and may occur with primary tumours arising above the brow line and without clear clinical signs of a mass causing orbital invasion. Sebaceous (meibomian gland) carcinoma has a propensity for intraepithelial pagetoid spread within the conjunctiva and skin and an apparently localised eyelid mass may actually widely involve the surface of the globe and eyelids, in some cases necessitating exenteration.
The commonest epithelial tumour to secondarily involve the orbit by direct invasion is squamous carcinoma arising in the paranasal sinuses or pharynx; extension can rarely occur without bone erosion, but by perineural spread through, for example, the ethmoid foramina or the inferior orbital fissure. Orbital involvement represents advanced disease and the prognosis is usually poor. Management often involves diagnostic biopsy and later wide surgical clearance (including exenteration if there is direct orbital involvement) with radiotherapy.
Other paranasal tumours that may involve the orbit by direct invasion are adenoid cystic carcinoma, adenocarcinoma, esthesioneuro-blastoma and melanoma.
Uveal malignant melanoma is the most common primary intraocular tumour in adults and may spread directly to the orbit through the emissary veins. More rarely, aggressive tumours may reach the orbit by direct scleral invasion or through the optic nerve head.To date, patients with orbital extension of uveal melanoma have a very poor prognosis as there is frequently systemic disease; future advances in tumour-directed chemotherapy may, however, improve the outlook for this situation.
Extraocular extension of retinoblastoma (the commonest intraocular malignancy in childhood) occurs in approximately 8% of patients, but can present later in life as a lump in an anophthalmic socket. After enucleation of the eyes with extrascleral extension of retinoblastoma, adjuvant treatment often combines systemic chemotherapy with orbital radiotherapy, although the prognosis is relatively poor.
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Complete Guide to Preventing Skin Cancer. We all know enough to fear the name, just as we do the words tumor and malignant. But apart from that, most of us know very little at all about cancer, especially skin cancer in itself. If I were to ask you to tell me about skin cancer right now, what would you say? Apart from the fact that its a cancer on the skin, that is.