1) Hyperostosis is seen in 25-49% of intracranial meningiomas and its cause is still debated. (2) The study found that 23.5% of meningiomas with radiological hyperostosis showed tumor invasion into the bone on histology. (3) The authors recommend removing any bone in contact with the tumor to achieve a complete resection, as tumor invasion can occur even without hyperostosis on imaging.

1. The Significance of Hyperostosis in
Intrancranial Meningioma and How It
Affects the Management
Nishant Goyal, Deepak Agrawal
Department of Neurosurgery
All India Institute of Medical Sciences, New Delhi, India

2. 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.

3. 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

4. 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

5. 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

6. 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

7. Methods: Radiology
O Preoperative MR imaging and CT scans
O 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

8. Methods: Radiology
Hyperostosis
MRI scan CT scan Bony cuts

9. Methods: Radiology
No Hyperostosis
MRI scan CT scan Bony cuts

10. Methods
Patients with preoperative diagnosis
of intracranial meningioma
Hyperostosis Hyperostosis
present absent
Bone sampling done Bone sampling done from
from hyperostotic bone in contact with the
region dural attachment of the
tumor

11. 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

12. 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

13. Results
Total number of cases with
preoperative diagnosis of intracranial
meningioma (n= 49)
Histopathological
examination
Non meningioma (n=9) Intracranial
(Excluded) meningioma
(n=40)
Study group

14. Results (n=40)
Males, 18 Females, 22

15. Results (n=40)
O Median age= 45.5 years
O Range= 20-65 yr
10 10 10
10
8 5 5
6
4
2
0
20-29 30-39 40-49 50-59 60-69
Age distribution

16. RADIOLOGY

17. Results (n=40)
Hyperostosi
Hyperostosi
s
s absent, 10
present, 30
(25%)
(75%)

18. Results (n=40)
Number of Hyperostosis
Location
cases present
Convexity 12 10 (83.3%)
Parasagittal & peritorcular, falcine
16 10 (62.5%)
and tentorial
Skull base 12 10 (83.3%)
Total 40 30 (75%)

19. Histopathology

20. Results (n=40)
19
20
15 8
10 6
4
5 2 1
0
Type of meningioma (On histopathology)

21. Results (n=40)
WHO Grade
WHO Grade I WHO Grade II
36 (90%) 4 (10%)

22. Results (n=40)
O MIB- 1 labeling index
O Range= 1 to 15
O Mean= 3.5

23. Results (n=40)
Tumor Invasion Into The Bone On
Histology
Absent
32 (80%)
Present
8 (20%)

24. Meningiomas (n=40)
Radiological evidence of hyperostosis
Hyperostosis Hyperostosis
present (n= 30) absent (n= 10)
Histological evaluation of bone
Bone No bone Bone No bone
invasion invasion invasion invasion
(n=7) (n=23) (n=1) (n=9)

25. 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

26. Results (n=40)
Location Number Tumor invasion
of cases present
Convexity 12 4 (33.3%)
Parasagittal & peritorcular, falcine 16 2 (12.5%)
and tentorial
Skull base 12 2 (16.7%)
Total 40 8 (20%)

27. 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)

28. Illustrative Cases

30. a b c
d e

31. a b
c d

32. 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: 905–912
Jääskeläinen 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: 461-469
Al-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

33. Discussion
O In 1957, Simpson elaborately described the
importance of degree of resection in
preventing recurrence in meningioma
Simpson Excision Recurrence at 10 yrs
Grade
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.

34. 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?

35. Discussion
O Our study shows that it is not possible to
predict which patients are likely to show bone
invasion on the basis of
O Preoperative radiology, as invasion can
occur without hyperostosis on radiology
O Intra-operative pathological evaluation of
bone is not feasible by frozen section
examination

36. 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

39. 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

40. 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

41. 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.

42. Thank you