CP ANGLE TUMOR.pptx

cmc

1. Cerebellopontine Angle Tumor DR SUJAN PANDEY SURGERY RESIDENT

2.  Outlines Anatomy of CPA Possible lesions of CPA Clinical features Differential diagnosis Radiology Diagnostic elements Treatment

3. CPA anatomy CP angle : Irregularly shaped extra-axial potential space Between cerebellum & pons in posterior fossa lateral to pre- pontine cisterns

4. Anatomy 1. Sensory root of trigeminal nerve 2. Pons 3. Vestibulocochlear nerve 4. Facial nerve 5. Abducent nerve 6. Medulla oblongata 7. Motor root of trigeminal nerve 8. Basilar sulcus

5.  BORDERS Medial : lateral surface of the brainstem Lateral : petrous bone Superior : middle cerebellar peduncle & cerebellum Inferior : arachnoid tissue of lower cranial nerves Posterior : cerbellar peduncle

6. CONTENTS   CSF Arachnoid tissue Cranial nerves Vessels

7. POSSIBLE LESIONS OF CP ANGLE Nerve structure : schwanoma (V-XII) Meninges : Meningioma ,arachnoid cyst & metastasis Cisternal space : epidermoid cyst , dermoid cyst & lipoma Vascular : aneurysms , AVM & paraganglioma Cerebellar ventricles : epindymoma ,lymphoma & glioma Skull base : chondroma ,pituitary adenoma & cholestrol granuloma

8. Clinical features Chochlear CN-VIII : asymmetric sensorineural hearing loss & tinnitus Vestibular CN-VIII : dysequilibrium & vertigo CN-VII : facial weakness CN-VI : lateral rectus palsy CN-IX : dysphagia CN-X : hoarsness & aspiration CN-XI : shoulder weakness CN XII:Tongue wasting and deviation Brainstem : headache ,visual loss & ataxia

9. Cerebellum : Nystagmus Finger-nose test Dysdiodokinesia ( the inability to perform rapid alternating muscle movements ) Intentional Tremor Scanning Speech Wide gait Falling on ipsilateral side Romberg sign(   positive test is the inability to maintain an erect posture over 60 seconds with eyes closed)

10. Differential Diagnosis Accoustic neuroma/Vestibular schwanoma Meningioma Epidermoid Arachnoid cyst Dermoid cyst Trigeminal neuroma Metastasis

11. Vestibular Schwanoma • Vestibular neuroma is a benign, slow growing, encapsulated tumor of vestibulocochlear (8th CN) cranial nerve. • It is also known as - Acoustic neuroma - Acoustic neurilomma -CPA tumor -Angle tumor

12. Most common CPA tumor 60-92% of CPA lesions Acute angle with petrous bone Benign & encapsulated tumor Schwann cells Rubbery tissue with nodular surface yellow and gray areas with interspersed foci of hemorrhage and cyst. Vestibular division of CN-VIII Inferior vestibular nerve > superior vestibular nerve.

13. Epidemiology • 10 in 1 millions • In USA-2000-30000 cases are diagnosed each year • 95%- Sporadic • 5%- associated with NF2-usually bilateral-early incidence • Epidemiological classification : 1.Silent tumors 2 . Symptomatic undiagnosed tumors 3.Diagnosed tumors

14. Classification Jackler classification : Intrameatal tumour Extrameatal size mm Grade 1 Small 1-10 Grade 2 Medium 11-20 Grade 3 Moderately large 21-30 Grade 4 Large 31-40 Grade 5 Giant > 40

15. Tumor extension classification

16. Pathology • Gross - Small to large size - encapsulated - slowly growing - medial to IAC and lateral to CPA • Microscopic - Antoni A cells - Antoni B cells

17. Histopathological types   Antonie A : spindle-shaped cells with rod-shaped nuclie , dense reticulin arranged in fascicles Antonie B : stellate cells smaller hyperchromatic nuclei Less reticulin prominent cytoplasmic processes large myxoid stroma

18. Clinical Presentation Age and sex 2 . Vestibulocochlear symptoms 3 . Cranial nerve involvement 4 . Brainstem involvement 5 . Cerebellar involvement 6 . Raised ICP

19. Intracanalicular :Hearing loss (UL progressive ), tinnitus, vertigo Cisternal : Worsened hearing and dysequilibrium Vestibulocochlear symptoms   : - Hearing loss- sensoryneural,usually unilateral - tinnitis - unsteadyness • Cranial nerve involvement: 7th CN: - Hitzelberger’s sign ( Hypoesthesia of the posterior meatal wall ) - loss of taste sensation - schirmer test:reduced lacrimation - delayed blink reflex

20. 5th CN - numbness of face - reduced corneal reflex 9th & 10th CN - dysphasia - horseness of voice 11th & 12th ,3rd, 4th, 6th CN –if tumor is very large • Brainstem involvement -ataxia - weakness and numness of arms and legs - exagerated tendon reflex

21.   Cerebeller involvement -ataxic gait - postural imbalance -tendency to fall towards affected side - dysdiadochokinesia • Raised ICP- Headache, vomiting,diplopia papiloedema,bluring of vision

22. Diagnostic Tests Audiometric Testing. Electrophysiologic Testing. CT Brain contrast with bone cuts. MRI brain contrast

23. Audiometric Testing Pure‐tone testing : u/l SNHL ‐ most commonly high frequency (65%).

24. Speech discrimination : Scores out of proportion with pure‐tone thresholds. Acoustic reflex thresholds : typically elevated or absent. If present then reflex decay measured. The sensitivity is 85% for detecting retrocochlear problem.

25. Electrophysiologic Testing ABR:Most sensitive & specific audiologic test. • In patients with VS , the ABR is partially or completely absent , or there is a delay in latency of wave V on the affected side.

26. Auditory brainstem response test (also known as ABR or BAER)

27. Radiologic Features of vestibular schwannoma CT: Non‐contrast : usually isodense to brain, calcification is rare IV Contrast: Over 90% of non‐treated tumors enhance homogeneously MRI: T1W – isointense to brain, hyperintense to CSF T2W – hyperintense to brain, iso /hypo‐intense to CSF Gadolinium – Intensenhancement of tumor on T1W

28. CT BRAIN

29. MRI brain

30. CONTRAST MRI

31. NF2

32. TRIGEMINAL SCHWANNOMA

33. Treatment Observation Surgery(1 st choice) Retrosigmoid Translabrynthine Middle Fossa Radiotherapy Conventional radiation therapy Stereotactic radiosurgery

34. observation Monitoring with serial MRI scans at yearly intervals.50% tumor will have no or little growth (<0.2mm per year ) for several year. Indications Advanced age Poor health Lack of symptoms Non‐progression of symptoms Only hearing ear Contraindications Young patient Healthy patient Symptomatic progression Compression of brainstem structures

35. BASIC REQUISITE FOR SURGERY CT scan brain plain and contrast Bone cuts of the skull base with 1.5 mm cuts to visualise the high lying jugular MRI scan brain plain and contrast study Instrument: Microscope Fine dissector set CUSA (if available )  Cavitron Ultrasonic Surgical Aspirator Facial nerve monitor (if available)

36. Positioning

37. PREOP

38. Retromastoid suboccipital approach

39. postop

40. Translabyrinthine approach Indications: Lesions where hearing preservation is not aimed at 1)Acoustic neurinoma : ‐ with bad preoperative hearing whatever be the size of the tumour 2) Meningiomas posterior to or centered to the internal auditory canal with poor hearing 3) Epidermoids , dermoids etc where poor hearing is present.

41. Translabyrinthine approach Contraindication s : Only hearing ear Ipsilateral CSOM

42. Translabyrinthine approach

43. PREOP POSTOP

44. Middle Fossa Indications : Small tumor Intracanallicular tumor Moderate CPA involvement Adequate hearing (SRT<50 db , Disc >50%) Contraindications : Large tumors Extensive CPA involvement ( > 0.5 – 1 cm ) Older patients ( > 60 yrs. may have higher rate of bleeding or stroke)

45. Post operative complications • Common : SNHL,temporary facial nerve palsy and balance problem, CSF leak, meningitis • Rare : stroke, intracranial bleeding, pneumocephalus , cerebellar ataxia, and even death.

46. Radiological • X-knife or Gamma knife surgery- 2nd treatment of choice • Cyber knife

47. Stereotactic Radiosurgery Indications : Small tumors Functional hearing Older patients (>75) Medically unstable patients Small residual lesion Contraindications: Tumors > 3 cm Prior radiotherapy Tumor compressing brainstem

48. SRS

49. Thank you

50.  Meningioma Second most common CPA lesion 3‐7 %. Arise from cap cells near arachnoid villi well-circumscribed globular or lobulated non-glial tumor arachnoidal cells:CN foramina , venous sinuses clearly demarcated from the brain Usually arise : posterior surface of petrous Usually do not extend : IAC

51. Symptoms: Ataxia. Nystagmus . Facial hypesthesia . Audiologic findings may show retrocochlear pattern or may be normal.

52. CT scan CT scan appearance shows a tumour of slightly increased density prior to contrast; it enhances uniformly with intravenous contrast. Hyperostosis of the cranial vault may also be seen.

53. Treatment The treatment of choice for meningiomas is complete excision of tumour . For small residual tumours , Stereotactic radiosurgery(SRS) may be advocated .

54. Preop postop

55. Epidermoid cyst Accounts for 2‐6% of CPA masses Physiology: Congenital lesions that present in adulthood Rests of ectodermal tissue containing stratified squamous lining and keratin May arise within the temporal bone or in the CPA Benign and slow growing Symptoms: Similar to acoustic neuroma and meningioma Facial nerve paresis and facial twitching may occur

56. Epidermoid cyst Extra-axial lesions which typically spread along the basal surface. Rupture can produce aseptic meningitis . Overwhelmingly benign.

57. Radiologic Features Cistern oriented with variable shape with a cauliflower surface appearance

58. Diagnostic elements Dumb bell into middle fossa or contralateral cistern Nonenhancing (25% mild peripheral enhancement ) CT usually shows a mass hypodense to CSF Inhomogeneous lesion, highly variable in shape with a cauliflower surface appearance .

59. Cerebellopontine Angle Arachnoid Cysts Arachnoid cysts are intraarachnoid masses of uncertain origin filled with CSF Often present with headache and ataxia. If symptoms are few, observation is advocated. Symptomatic lesion require Marsupilization of cyst rather than excision or shunting.

60. Diagnostic elements Avascular cystic mass Nonenhancing Smooth regular shape Homogeneous identical signal to CSF in all weighting No calcifications FLAIR :intense signal suppresion Diffusion weighting : hypointensity (no restriction of diffusion)

61. Imaging