Prospective study of Meningioma & diagnostic validity of MIB-1 index in grading of meningioma

Background: Meningioma is one of indolent neoplasm. Meningiomas may make their appearance in childhood or adolescence, but most are encountered in middle or later adult life. Females are affected more commonly than males. Aims: (1) Categorization of meningioma cases on basis of WHO (2007) classification. (2) Evaluation of clinico-radiological data & correlation with histopathology grade of meningioma. (3) Role of ki67 (MIB-1) index in grading of meningioma. (4) Evaluate the validity of MIB-1 index in grading of meningioma. Methods and Material: This is prospective study conducted at Department of Pathology at Gujarat Cancer and research Institute, Ahmedabad. Total number of cases enrolled in study was 90 and it was carried out over period of September 2013 to December 2015 after being approved by the ethical committee of the Institute. Patients selection were done from details of all cases, histomorphology, radiology and immunohistochemistry (IHC) - MIB-1 confirmed by Meningiomas. Surgically resected frozen tissue and specimen section included in study. Results: MIB-1 LI and the 4 parameters used in the WHO grading system, namely, mitotic index, increased cellularity, sheet-like architecture and small cell formation showed good correlation. There was a poor correlation with certain other histological parameters, such as necrosis, cellular pleomorphism and brain invasion. MIB-1 labeling index less than 7% mostly are benign in nature and greater than 7% favors atypical or anaplastic. Conclusions: The MIB-1 LI has highest validity at a level of 7% in the diagnosis of histological atypia in meningiomas. Most of meningiomas, which are missed in appropriate grading on biopsy can be due to focal involvement of atypia. This study is helpful for pathologist for appropriate diagnostic grading and for the surgeon to take appropriate surgical decision and to follow up the same cases. In combination, histomorphological features and MIB-1 LI definitely help in identifying po