The Significance of Hyperostosis in Intrancranial Meningioma and How It Affects the Management

Nishant Goyal, Deepak AgrawalDepartment of Neurosurgery

All India Institute of Medical Sciences, New Delhi, India

Introduction

O Association between meningioma and hyperostosis

O Hyperostosis is seen in 25-49 % of intracranial meningiomas*

•Cushing H. The cranial hyperostoses produced by meningeal endotheliomas. Arch Neurol Psychiatry 1922; 8: 139-154•Cushing H, Eisenhardt L. Meningiomas: Their Classification, Regional Behavior, Life History and Surgical End Results. Springfield, Charles C Thomas, 1938. • Frazier CH, Alpers BJ. Meningeal fibroblastomas of the cerebrum. Arch Neurol Psychiatry 1933; 29: 935–989.• Spiller WG. Hemicraniosis and cure of brain tumor by operation. JAMA 1907; 49: 2059–2065.

Introduction

O Cause of hyperostosis still a matter of debate

O Occurs as a reactionary change to meningioma

O Due to tumor invasion into the bone

O Common practice is to drill the hyperostotic bone & place the bone flap back

Hypothesis

O Bone changes seen in meningioma can be attributed to tumor invasion

O Leaving the bone flap in situ may be same as leaving a part of the tumor behind

Methods

O Study design: Prospective

O Study period : October 2010- July 2011 (10 months)

O Consecutive patients with a preoperative diagnosis of intracranial meningioma who underwent surgery

Methods

O Inclusion criteria-O All cases of intracranial meningioma (on

histopathology) who were operated in our institute during study period

O Exclusion criteria-O Intracranial tumors other than

meningioma (on histopathology)O Tumors in which bone biopsy was not

available

Methods: Radiology

O Preoperative MR imaging and CT scansO Examined individually by two

neurosurgeons to assess for bone thickening overlying the tumor

O Present when there was consensus among the two

O The cases of meningioma were classified according to location

CT scan Bony cuts

Hyperostosis

Methods: Radiology

MRI scan

CT scan Bony cuts

No Hyperostosis

Methods: Radiology

MRI scan

Hyperostosis present

Bone sampling done from hyperostotic

region

Patients with preoperative diagnosis of intracranial

meningioma

Bone sampling done from bone in contact with the dural attachment of the

tumor

Hyperostosis absent

Methods

Methods: Histopathology

O Tumor tissue was processed as is routine for histopathological examination

O Bone was decalcified and then processed

O Hematoxylin and eosin stained slides of tumor tissue and bone sample were examined by two neuropathologists

Methods: Histopathology

Features assessed on histopathology:

WHO Grade and Type of meningioma

MIB-1 labeling index (MIB-1 LI)

Presence of tumor invasion into the bone

Total number of cases with preoperative diagnosis of

intracranial meningioma (n= 49)

Non meningioma (n=9)(Excluded)

Intracranial meningioma

(n=40)

Study group

Histopathological examination

Results

Males; 18 Females; 22

Results (n=40)

Results (n=40)

O Median age= 45.5 years O Range= 20-65 yr

20-29 30-39 40-49 50-59 60-690

2

4

6

8

10

5

10 10 10

5

Age distribution

RADIOLOGY

Results (n=40)

Hypero-stosis

present, 30 (75%)

Hypero-stosis

absent, 10 (25%)

Results (n=40)

LocationNumber of

cases

Hyperostosis

present

Convexity 12 10 (83.3%)

Parasagittal & peritorcular, falcine

and tentorial16 10 (62.5%)

Skull base 12 10 (83.3%)

Total 40 30 (75%)

Histopathology

Results (n=40)

0

4

8

12

16

2019

2

68

14

Type of meningioma (On histopathology)

Results (n=40)

WHO Grade I

36 (90%)WHO

Grade II4 (10%)

WHO Grade

Results (n=40)

O MIB- 1 labeling index O Range= 1 to 15O Mean= 3.5

Results (n=40)

Present 8 (20%)

Absent32 (80%)

Tumor Invasion Into The Bone On Histology

Meningiomas (n=40)

Hyperostosis present (n= 30)

Radiological evidence of hyperostosis

Histological evaluation of bone

Bone invasion

(n=7)

No bone invasion (n=23)

Bone invasion

(n=1)

No bone invasion

(n=9)

Hyperostosis absent (n= 10)

Results (n=40)

O Of the eight cases showing tumor invasion into the bone on histology

O Seven had hyperostosis on radiology

O One without hyperostosis

Results (n=40)

Location Number

of cases

Tumor invasion

present

Convexity 12 4 (33.3%)

Parasagittal & peritorcular, falcine

and tentorial

16 2 (12.5%)

Skull base 12 2 (16.7%)

Total 40 8 (20%)

Results (n=40)

O Tumor invasion into the bone O Three cases of meningothelial

meningiomas (3 out of 8 cases; 37.5%) O Five cases of transitional meningiomas

(5 out of 19 cases; 26.3%)

O Tumor invasion into the bone did not show any significant correlation with WHO grade, type and MIB-1 labeling index in our study (p>0.05)

Illustrative Cases

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b

d

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Discussion

O A number of studies have upheld the principle that clinical success in meningioma surgery is related to the extent of resection

Bikmaz K, Mrak B, Al-Mefty O. Management of bone-invasive, hyperostotic sphenoid wing meningiomas. J Neurosurg 2007; 107: 905–912Jääskeläinen J. Seemingly complete removal of histologically benign intracranial meningioma: Late recurrence rate and factors predicting recurrence in 657 patients-A multivariate analysis. Surg Neurol 1986; 26: 461-469Al-Mefty O, Kadri PA, Pravdenkova S, Sawyer JR, Stangeby C, Husain M. Malignant progression in meningioma: documentation of a series and analysis of cytogenetic findings. J Neurosurg 2004; 101: 210–218

Discussion

O In 1957, Simpson elaborately described the importance of degree of resection in preventing recurrence in meningioma

Simpson Excision Grade

Recurrence at 10 yrs

I 9%

II 19%

III 29%

IV 40%Simpson D. The recurrence of intracranial meningiomas after surgical treatment. J Neurol Neurosurg Psychiatry 1957; 20: 22-39.

Discussion

O Simpson Grade I excision of meningioma O Macroscopically complete removal of

tumor with excision of its dural attachment and any abnormal bone

O What is abnormal bone?

Discussion

O Our study shows that it is not possible to predict which patients are likely to show bone invasion on the basis ofO Preoperative radiology, as invasion can

occur without hyperostosis on radiology

O Intra-operative pathological evaluation of bone is not feasible by frozen section examination

Discussion

O Therefore, in order to achieve better Simpson grade of tumor excision one should remove as much bone in contact with the tumor as possible in all cases

Limitation

O The possibility of sampling error can not be completely ruled out

O The actual incidence of bone invasion is likely to be higher than in our study

Conclusion O A significant number of patients

(23.5% in our study) with radiological hyperostosis have tumor invasion into the bone

O However, the absence of hyperostosis does not mean the absence of tumor invasion

Conclusion O We recommend that one should

remove the bone (flap) whenever possible in order to achieve complete excision of intracranial meningioma in close proximity to bone and use synthetic material to cover the defect.

Thank you