Clinicopathological study of Meningioma

Meningiomas are the most common primary non-glial intracranial brain tumours arising from the meninges [1]. Harvey Cushing coined the name "MENINGIOMA", in1922 for the most common dural based tumor, accounting for 15-30% of all primary Intracranial tumors [2]. The meningiomas arise from the arachnoid cap cells of the arachnoid villi in the meninges. These tumours usually are benign in nature, however, a small percentage are cancerous. More than 90% of all meningiomas are solitary. Exact etiology is unknown. Ionizing radiation is the only established environmental risk factor for Clinicopathological study of Meningioma Patel JP.1, Jansari TR.2*, Chaudhari VV.3 DOI: https://doi.org/10.17511/jopm.2020.i01.02


Introduction
Meningiomas are the most common primary non-glial intracranial brain tumours arising from the meninges [1]. Harvey Cushing Meningioma, with higher risk among people who were exposed in childhood than as adults. They can occur at any age, median age being 65 years, with risk increasing with increasing age. It has a female preponderance, with a female/male ratio of  Majority of the patients (50%), were in the age group of 41-60 years, this was followed by 30% patients in the age group of 21-40 years (Table 2).  Figure 1).  In this study, according to WHO grading system of meningioma tumors, out of 30 cases 28 were stated as Grade I and 2 meningiomas were stated as Grade II (Table 4). Most of the meningiomas were found in the intracranial region (20, 66.7%) (Table 5, Figure 2).
Posterior fossa was the most favoured site (5,25%)     (Table 6).  Some studies have found psammoma bodies to have a protective role [13].
In meningothelial meningioma, the meningothelial cells were arranged in syncytium and lobules. These lobules were separated by thin collagenous septae.
Most of these cases showed oval nuclei with delicate nuclear chromatin. Some cases showed rounded eosinophilic cytoplasmic invaginations, and some cases demonstrated central nuclear clearing. There were 4 cases (13.33%) of meningioma, 2 cases (6.66%) of atypical meningioma ,1 case (3.33%) of fibrous meningioma and 1 case (3.33%) of secretory meningioma in the present study. Atypical meningiomas include types having certain histological parameters that are associated with increased risk of recurrence and more aggressive behaviour than benign forms. These include meningioma with (a) mitotic index more than 4 per 10 high power fields OR (b) 3 of the 5 features which include-pattern less growth, hypercellularity, high nucleus: cytoplasm ratio, macronucleoli and geographic areas of necrosis OR (c) Brain invasion [29].
Immunohistochemistry (IHC) mainly has a role in differential diagnosis, for example, when Limitations to the study is, it's a single institutionbased study restricted by small sample size.

Conclusion
Meningiomas are slow growing neoplasm that exhibits a remarkably wide range of clinical spectrum and histological appearances with female preponderance. They usually present with headache and vomiting and are frequently located intracranially. Majority are grade I meningiomas with psammomatous meningioma as commonest variant, belonging to WHO grade I meningiomas are readily curable by resection. Few histological features and variants are associated with aggressive behaviour and high risk of recurrence. Thus, accurate histopathological diagnosis and grading of these tumors is essential to improve the accuracy and reproducibility.
What the study adds to the existing knowledge?
The present distribution of histomorphologic spectrum of meningioma is similar to most of the other studies worldwide as stated in discussion. However, the present study had only few cases of atypical meningioma as compared to others. Immunohistochemistry in prospective study may provide more details and elaborate the facts.