Clinico-Histomorphological and Mib-1 Analysis of Recurrent Meningiomas: A Retrospective Study

Meningiomas are the most common primary brain tumors in adults, comprising 37.6% of central nervous system neoplasms. Though gross total resection is the treatment of choice, meningiomas recur even after complete resection. Additionally, meningiomas with a high Ki67/MIB-1 labeling index (LI) have a higher recurrence rate.

This article analyzes the clinico-histomorphological features of recurrent meningiomas and compares the expression of MIB-1 LI of primary and recurrent tumors.

This was a retrospective observational study of 50 recurrent meningiomas diagnosed between 2019 and 2023. Tumors were analyzed for site, radiological/histopathological features, and expression of MIB-1 LI in both primary and recurrent tumors.

Thirty-four percent of the recurrent cases were between 41 and 50 years of age, 58% of the recurrent cases were males. Recurrence was most commonly seen in the frontal region (26%; n  = 13) and 52% cases recurred between 1 and 10 years after primary resection. Of the primary tumors, 30 cases (60%) were grade 1, 16 cases (32%) were grade 2, and 4 cases (8%) were grade 3. Mean MIB-1 of primary meningiomas was 4.25% overall and 1.8% for grade 1. Progression in grade was noted in 15 cases with 5 cases showing brain invasion on recurrence while 17/30 grade 1, 14/16 grade 2, and 4/4 grade 3 tumors recurred with no change in grade. Overall mean MIB-1 LI of recurrent tumors was 5.4%.

Although MIB-1 LI is not an independent criterion for tumor grading, it can be used as an additional tool to identify at-risk patients and recommend close follow-up.