The Significance of Hyperostosis in Intrancranial Meningioma and How It Affects the Management Nishant Goyal, Deepak Agrawal Department of NeurosurgeryAll India Institute of Medical Sciences, New Delhi, India
IntroductionO 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.
IntroductionO Cause of hyperostosis still a matter of debate O Occurs as a reactionary change to meningioma O Due to tumor invasion into the boneO Common practice is to drill the hyperostotic bone & place the bone flap back
HypothesisO Bone changes seen in meningioma can be attributed to tumor invasionO Leaving the bone flap in situ may be same as leaving a part of the tumor behind
MethodsO Study design: ProspectiveO Study period : October 2010- July 2011 (10 months)O Consecutive patients with a preoperative diagnosis of intracranial meningioma who underwent surgery
MethodsO Inclusion criteria- O All cases of intracranial meningioma (on histopathology) who were operated in our institute during study periodO Exclusion criteria- O Intracranial tumors other than meningioma (on histopathology) O Tumors in which bone biopsy was not available
Methods: RadiologyO 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 twoO The cases of meningioma were classified according to location
Methods: Radiology No HyperostosisMRI scan CT scan Bony cuts
Methods Patients with preoperative diagnosis of intracranial meningioma Hyperostosis Hyperostosis present absentBone sampling done Bone sampling done from from hyperostotic bone in contact with the region dural attachment of the tumor
Methods: HistopathologyO Tumor tissue was processed as is routine for histopathological examinationO Bone was decalcified and then processedO 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
Results Total number of cases with preoperative diagnosis of intracranial meningioma (n= 49) Histopathological examinationNon meningioma (n=9) Intracranial (Excluded) meningioma (n=40) Study group
Results (n=40) 192015 810 6 4 5 2 1 0 Type of meningioma (On histopathology)
Results (n=40) WHO GradeWHO Grade I WHO Grade II 36 (90%) 4 (10%)
Results (n=40)O MIB- 1 labeling index O Range= 1 to 15 O Mean= 3.5
Results (n=40)Tumor Invasion Into The Bone On Histology Absent 32 (80%) Present 8 (20%)
Meningiomas (n=40) Radiological evidence of hyperostosis Hyperostosis Hyperostosis present (n= 30) absent (n= 10) Histological evaluation of bone Bone No bone Bone No boneinvasion invasion invasion invasion (n=7) (n=23) (n=1) (n=9)
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 Tumor invasion of cases presentConvexity 12 4 (33.3%)Parasagittal & peritorcular, falcine 16 2 (12.5%)and tentorialSkull 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)
DiscussionO 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
DiscussionO 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.
DiscussionO Simpson Grade I excision of meningioma O Macroscopically complete removal of tumor with excision of its dural attachment and any abnormal boneO What is abnormal bone?
DiscussionO 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 radiologyO Intra-operative pathological evaluation of bone is not feasible by frozen section examination
DiscussionO 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
LimitationO The possibility of sampling error can not be completely ruled outO The actual incidence of bone invasion is likely to be higher than in our study
ConclusionO A significant number of patients (23.5% in our study) with radiological hyperostosis have tumor invasion into the boneO However, the absence of hyperostosis does not mean the absence of tumor invasion
ConclusionO 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.