Tumours

1. Dr. Mohammad Shehadeh Salam Hirbawi Tumours

2. Optic nerve glioma • Slow-growing. • Pilocytic astrocytomawhich typically affects children. • girls more often than boys. • Approximately 30% of patients have associated nurofibromatposis-1 and in these patients the prognosis is better.

3. Presentation: • Most frequently in the first decade of life(median age 6.5 years). • Slowly-progressive visual loss, followed later by proptosis. • Although this sequence may occasionally be reversed. • Acute loss of vision as a result of haemorrhage into the tumour is uncommon.

4. Signs: • Proptosis often with inferior dystopia. • The optic nerve head is initially swollen and subsequently becomes atrophic. • Opticociliary collaterals and central retinal vein occlusion are ossasionally seen. • Intracranial spread to the chiasm and hypothalamus may develop.

6. CT: • shows a fusiform enlargement of the optic nerve with a clear cut margin produced by the intact dural sheath.

7. MR: • Shows gliomas. • may also show intracranial extension. Treatment: • May not be required in patient with no evidence of growth,Good vesion and no cosmetic deformity. • surgical excision with preservation of the globe is required for large or growing tumours that are confined to the orbit particularlly if vision poor and proptosis significant. • Radiotherapy may be combined with chemotherapy for tumours with intracranial extension.

8. Prognosis: • Variable. • Some tumours have an indolent course with little growth. • Others may extent intracranialy and threaten life.

9. NB: • malignant gliomas are rare & almost always occur in adults. the prognosis is very poor with almost certain death within one year of diagnosis.

10. Optic nerve sheath meningioma • Arise from meningothelial cells of the arachnoid villy surroundings the intraorbital or less commonly the intracanalicular portion of the optic nerve. • In some cases the tumour merely encircles the optic nerve whilst in others it invades the nerve by growing along the fibrovascularpialseptae. • Primary optic nerve sheath meningiomas typically affect middle-aged women.

11. (c) axial CT of small tumor shows slight thickening & calcification (d)axial T2-weighted MR in a more advanced case shows fusiform enlargement of the optic nerve & proptosis

12. Presentation: • With gradual unilateral visual impairment . • Transient obscurations of vision may be the presenting symptom. Signs: • The classical triad is: Visual loss,optic atrophy,opticociliary shunt vessels.

13. However, the simultaneous occurrence of all three signs in one individual is uncommon. • The sequence of involvement is as follows: • Optic nerve dysfunction & chronic disc swelling followed by atrophy. • Opticocilliary collaterals found in about 30% of cases, regress as optic atrophy supervenes. • Restrictive motility defects, particularly in up-gaze, because the tumour may splint the optic nerve. • Proptosis caused by intraconal spread-usually develops after the onset of visual loss.

14. NB: • this sequence is the opposite of that seen with tumours outside the dural sheath, in which proptosis develops long before optic nerve compression. CT: • Shows thickening & calcification of the optic nerve. MR : • More clearly detects smaller tumours & those around the optic canal.

15. Treatment: • May not be required in middle-aged patients with slow-growing tumours because the prognosis is good. • Surgical excision is required in young patients with aggressive tumours, particularly if the eye is also blind. • Fractionated stereotactic radiotherapy may be appropriate in selscted cases or as adjunctive treatment following surgery. Prognosis: • Is good in adults, although the tumour may be more aggressive & sometimes fatal in children.