[Pathology features of recurrent meningioma]

One of the main prognostic factors for meningioma recurrence is histological diagnosis with an assessment of tumor grade. Despite this, there are no clear microscopic criteria for recurrence prognosis in benign forms, and there is no common understanding of meningioma recurrence and continued growth clinical management.

To evaluate neuroimaging, microscopic features and proliferative activity in meningioma recurrence and continued growth.

Histological and immunohistochemical studies of tumor biopsies were performed in 16 patients with tumor progression who underwent surgery for recurrence and continued growth of intracranial meningiomas; the comparison group included 10 patients with newly diagnosed intracranial meningioma. All patients were performed pathomorphological and radiological examination assessment.

The average tumor volume in the meningioma progression group was 48.88±14.32 cm³; the average tumor volume was higher in the primary surgical treatment group - 51.51±14.48 cm³. Recurrent tumors were characterized by more pronounced cellular and tissue atypia, patterns of infiltrative growth with the involvement of large vessels. The meningioma proliferative activity, assessed by Ki-67(max) expression, was higher in the group with meningioma progression and amounted to 9.71±2.5%. Significant differences in the Ki-67 expression were noted by tumor localization, grade, and brain invasion (p<0.05) in the meningioma recurrence and continued growth group.

Recurrent meningiomas are represented by different grade tumors, including benign typical meningioma (grade 1), which indicates the need for greater attention and patient follow-up with this pathology. There are differences in terms of grade progression and locally destructive growth in meningioma recurrence and continued growth. This indicates a more pronounced biological tumor aggression. The Ki-67 expression is an important prognostic factor in meningioma progression group.