16 Tumours of the orbit. Parasitic Diseases
Orbital tumours can be divided into primary, secondary and metastatic.
Primary tumours are those arising from the various orbital structures e.g vascular tumours- haemangiomas, adipose tissue tumours- liposarcoma, fibrous tissue tumours- fibroma etc. Secondary tumours spread from the surrounding structures and metastatic tumours are from distant primary tumours.
Secondary tumours
- Tumors of the eyeball- retinoblastoma
- Tumors of the eyelids- squamous and basal cell carcinoma
- Tumours of cranial cavity- invading orbit are glioma and meningioma
Metastatic tumours
- Neuroblastoma- from adrenal and sympathetic chain
- Nephroblastoma- from kidneys
- Carcinoma- from lungs, breast, prostate, thyroid and rectum
- Malignant melanoma- from skin
- Ewings sarcoma- from the bones
Capillary haemangioma
Clinical Picture- Presents in infancy with an anterior orbital swelling, features which may increase in size when crying. A similar eyelid skin lesion, a ‘strawberry naevus’ may also be present.
Management- Steroids injected into the lesion or given systemically are effective but the tumour often disappear spontaneously. Indications for treatment are optic nerve compression, ocular dysfunction or exposure keratitis.
Cavernous haemangioma
Clinical Picture -The most common benign orbital tumour in adults. Presents features in young adults with painless axial proptosis of gradual onset.
Management -Surgical excision.
Orbital varices
Clinical Picture- Dilated orbital veins. Presentation is at any age with: features
- Intermittent unilateral non-pulsatile proptosis
- Visible lesions in the eyelids or conjunctiva
- Acute orbital haemorrhage or thrombosis (less common).
Management -Surgical excision may be required.
Rhabdomyosarcoma
Clinical Picture-This very rare but aggressive tumour typically presents at features about the age of 7 years with rapidly progressive proptosis and a palpable mass may be present. It arises from the extraocular muscles
Management - Incisional biopsy followed by radiotherapy and chemotherapy.
Neural tumours
Optic nerve glioma presents in childhood with slowly progressive proptosis and visual loss. The optic disc may be swollen or pale. 25–50% of patients have neurofibromatosis-1.
Optic nerve sheath meningioma Typically affects middle- aged females and causes slowly progressive visual loss followed later by proptosis. The optic disc frequently shows opticociliary shunt vessels.
Management- Options include observation, surgery and radiotherapy.
Dermoid cyst
Clinical Picture-Variable age at presentation, with proptosis and/or a features palpable mass depending on site and size. They arise from an embryonic displacement of the epidermis to a subcutaneous location. Dermoid cysts are of two types: simple dermoid- seen in infancy and complicated-seen in adolescence
Management- Excision which must be complete.
Parasitic diseases of the orbit
- Trichinellosis (trichinella spiralis)
- Onchocercosis (Onchocerca volvulus)