Introduction
In 1922, Harvey Cushing coined the term “ meningioma”.1 Meningiomas are mostly benign tumors (~95%) and usually accounts for 33.8% of the total CNS tumors.2 In males, it accounts for ~20% while in females it accounts for 38% of total intracranial tumors.3,4 There is a feminine predominance of meningioma in most of the studies. The female-to-male ratio is about 2:1.5 Risk of tumour increases with age. Meningiomas constitute 0.4 to 4.6% of all brain tumors in children (younger than 16 years).6,7,8,9,10,11 They are extremely uncommon in infancy. The average age of presentation is 12.81 years as com pared to 6.3 years in other paediatric brain tumors.12,13 Some of the possible risk factors associated are ionising radiation,14,15 head trauma,16 breast cancer17 and genetic factors.18 It is presumed that the tumour arises from “arachnoid cap cells”.
The distribution of intracranial meningiomas is approximately as follows: convexity (35%), parasagittal (20%), sphenoid ridge (20%), intraventricular (5%), tuberculum sellae (3%), infratentorial (13%) and others (4%).19 In children, the tumour may arise in unusual sites. Eleven percent of meningiomas in children are intraven tricular, compared with 3.9% in adults.
The 2007 World Health Organization (WHO) classification of tumors of the CNS classified meningiomas under the heading “ tumours of the meninges ” and the subheading “ tumours of meningothelial cells.” WHO recognizes three grades based on pathologic criteria and the risk of recurrence and aggressive growth as grade 1(benign), grade 2 (atypical) and grade 3 (malignant).
Grossly, meningiomas are tan, well-demarcated solitary masses with a firm, broad-based dural attachment and smooth or bosselated surfaces. Falcine or tentorial meningiomas may have a bilobed, dumbbell shape. Except for aggressive variants, meningiomas are readily detachable from underlying brain or spinal cord. Similarly, haemorrhage and necrosis are usually restricted to malignant tumors. Increased vascular markings, calcification and hyperostosis are the characteristic findings that can be appreciated on plain radiographs.19 On NCCT(Non contrast CT), meningiomas are typically isodense to mild hyperdense compared with surrounding brain parenchyma.19 Calcification may be seen in some cases. Meningiomas usually have intense homogenous enhancement. On T1 weighted MRI, 60% of meningiomas are isointense and 30% are mildly hypointense compared with surrounding grey matter. On T2-weighted images, the tumor s are isointense or mild to moderate hyperintense in approximately 50% of the cases. Hyperintensity on T2-weighted images corresponds higher water content which suggests friable tumour that could be easily suctioned out during surgery. Meningiomas usually have intense homogenous enhance ment after injection of dye showing typical dural tail sign.19
Hospital based registry system forms the bulk of the reporting system in India. As per the literature, previously no studies h ave been published yet portraying meningioma incidence in rural population of central India. The aim of this study was to determine the incidence of Meningioma among all CNS tumors occurring in the study period, age and sex predilection, location, site preference for a population in a rural setup of central India.
Materials and Methods
This study is retrospective observational study from the period of January 2014 to Feb 2019 in MGIMS, Sewagram. Ethical board permission was taken. Inclusion criteria consists of all the histopathological proven cases of meningioma in department of Neurosurgery, MGIMS Sewagram during the same period. Rest of the CNS tumors will be excluded from the study. WHO 2007 classification of brain tumor was used for grading and typing of meningioma. Age, sex incidence and location of meningiomas was also studied. We also compared our results with other related studies.
Results
Out of 168 cases of CNS tumors operated, menigioma consists of 44 cases (26.19%). Out of 44 cases 37(84.09%) were intracranial menigioma and 7(15.91%) were spinal meningioma. The average age of presentation was 44.1 years. M:F ratio of 1:1.32. Most common affected age group was 30-50 years comprising 24 cases (54.54%) (Table 1). The M:F ratio in this age group was 1:2.4. The most common clinical symptoms for intracranial cases were headache followed by seizures and vomiting (Table 2). Among intracranial meningioma, the most common location was convexity meningioma (40.54%) followed by parasagittal (13.51%) and parafalcine meningioma(10.81%) (Table 3). Most common histopathological variety encountered was meningothelial in 42.72% cases. WHO grade I consists of majority of the tumors (95.45%) while grade II consists of 4.55%. In our study there was no grade III tumour reported. Out of 7 intraspinal meningioma the most common location was dorsal spine with 5 cases (71.42%).
Table 1
| Age | M | F | Total | Percent |
| <20 | 1 | 0 | 1 | 2.27 |
| 20-30 | 4 | 3 | 7 | 15.91 |
| 31-40 | 3 | 8 | 11 | 25 |
| 41-50 | 4 | 8 | 12 | 27.27 |
| 51-60 | 4 | 3 | 7 | 15.91 |
| >60 | 3 | 3 | 6 | 13.63 |
Age and sex incidence of meningioma.
Table 2
| Symptoms | n |
| Headache | 22 |
| Seizure | 14 |
| Vomiting | 8 |
| Paresis | 7 |
| Visual Disturbance | 5 |
| Alt. Consiousness | 4 |
Presenting complaints
Table 3
Location of meninginoma
Table 4
Comparison of location with other studies
Table 5
Comparison of tumour histopathology
Discussion
Meningioma accounts for 33.8 percent of brain tumor.2 In our study it consists of 26.19% of brain tumor similar to the studies by Ruberti RF et al20 and AB shah et al.28 Our study had female preponderance with M :F ratio of 1:1.3. In other study by Rohringer et al,21 M:F ratio was 1:2 wile in study by Howng and Kwan the ratio was 1:1.94.22 The cause of less male to female ratio as compared to other studies is not known. It could be due to less reporting of female for medical care in rural setup. In our study, 27.2% of our study population falls in 40-50 age group while 54.5% falls in 30-50 age group, which was similar to the study by Ruberti R.F.20 For 30-50 years study population the male: female ratio observed was 1:2.4. In our study we have only one case of pediatric meningioma. The most common location of tumor was convexity meningioma followed by parasagittal meningioma, which correlates well with study done by Rohringer et al21 and Howng and Kwan et al22 (Table 4).
Spinal meningiomas comprised of 15.9% of total meningiomas in our study. In study done by Solero CL et al spinal meningiomas consist of 7.5-1 2.7% of all CNS meningiomas.$ Dorsal spine is reported as the most common location for spinal meningioma.29,30,31 Out of 7 meningioma cases, 5 tumor cases were present in dorsal spine (71.4%). The male : female ratio for spinal meningioma was 1:6 which was similar to the stud y done by Shrilakshmi et al having ratio of 1:7.23
The most common histopathological entity encountered in our study was meningothelial variant (47.72%). Other variants observed in our study were Psammomatous (13.63%), transitional (13.63%), fibroblastic (11.36%), angiomatous (9.09%) and atypical (4.54%) variant. Sangamithra et al,24 Nasrin Samadi et al,25 Gursan et al,27 all reported menigothelial as the most common variety. S Babu et al26 reported transitional as most common variety (Table 5). Singh Avninder et al. reported that papillary meningiomas and anap lastic meningiomas constitute 1–2.5% of all meningiomas hence being rarest.32
Meningiomas are graded into Grade I, Grade II and Grade III with incidence in a ratio of 95.45%, 4.55%, 0% in this study. Nasrin Samadi et al25 reported as 86.1%, 8%, 5.9% while Konstantinos Violaris et al33 as 89.82% ,5.82%, 4.36% for Grade I, Grade II and Grade III tumours respectively. Gross total resection (GTR) was done in 39 cases (88.63%) and subtotal resection was done in five cases (11.36%) in the present study. The major postoperative complication in our study was postoperative seizures (22.72%) followed by hemiparesis and behavioral changes.
Conclusion
At present there is no clinicopathological study about meningioma for rural population of central India. Being a major tertiary centre in rural area, the population of this study could roughly represent the rural population.
From our study, we conclude that most common histopathological variants of meningioma are meningothelial meningioma, followed by psammomatous meningioma. Most common WHO grade is grade 1. The most common age group for presentation of meningioma is third to fifth decade of life, and it is least common among children. Although the male to female ratio in our study is 1:1.3 it is less as compared elsewhere in world. It could be due to less reporting of female for medical care in rural setup.
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