Meningioma Prognostic Tool Based on Correlation of Histopathological Grading and Immunohistochemistry.

OBJECTIVES

Meningiomas are slow-growing brain neoplasms classified into three grades based on morphological criteria. While these grades are simple, they do not always correlate with patient outcomes. This study aimed to evaluate the status of estrogen receptor (ER), progesterone receptor (PR), and proliferation marker Ki-67/molecular immunology borstel-1 (MIB-1) in the three grades of meningioma.

METHODS

We evaluated the data of meningioma patients who were seen in our tertiary center over 10 years-8.5 years retrospectively and 1.5 years prospectively. Their archival hematoxylin and eosin stained slides were reviewed and re-graded according to the World Health Organization 2021 criteria. Immunohistochemical analysis for ER, PR, and Ki-67 was performed on all grade 2 and grade 3 meningiomas and 30 cases of grade 1 formalin-fixed, paraffin-embedded samples.

RESULTS

Of the 276 cases included in the study, there were 231 (83.7%) cases of grade 1 meningioma, 34 (12.3%) cases of grade 2, and 11 (4.0%) cases of grade 3. ER was positive in 26.0% of grade 1 tumors, 5.8% of grade 2, and 0.0% of grade 3. PR was positive in 70.0% of grade 1 tumors, 20.0% of grade 2, and 18.0% of grade 3. The Ki-67/MIB-1 labeling index (LI) was 2.1 in grade 1, 6.3 in grade 2, and 13.4 in grade 3 tumors. For both PR and Ki-67, the differences between grades 1, 2, and 3 tumors were significant ( < 0.001). There was a significant inverse relationship between mean Ki-67 LI and PR status, with increasing grade of tumor.

CONCLUSIONS

Ki-67/MIB-1 LI has significant positive correlations with meningioma grade and its recurrence, which makes it a useful auxiliary method for the routine assessment of meningiomas, especially in patients with borderline atypia. The expression of PR, on the other hand, is a positive prognostic indicator and has a substantial correlation with histological grade. In cases of subtotal resection, high proliferative/recurrence rates, and borderline histopathology, the PR status in combination with the MIB-1 LI can offer insights into the behavior and the recurrence probability of a meningioma.