A 45-year-old woman with NF2 (neurofibromatosis type 2) has bilateral acoustic schwannomas and a meningeal mass. The meningioma on histology shows whorling of meningothelial cells and psammoma bodies. Which WHO grade is most common for meningioma?

• A WHO Grade 2 (atypical)
• B WHO Grade 3 (anaplastic/malignant)
• C WHO Grade 1 (benign) ✓
• D WHO Grade 4 (glioblastoma equivalent)

Explanation

Approximately 80% of meningiomas are WHO Grade 1 (benign), showing whorling meningothelial cells, psammoma bodies (laminated calcifications), and slow growth with low recurrence after complete resection. WHO Grade 2 (atypical) shows increased mitotic activity (≥4 per 10 HPF), brain invasion, or 3 of 5 histological features (sheeting, prominent nucleoli, small cells, macronuclei, necrosis) and has higher recurrence. Grade 3 (anaplastic) is rare and highly aggressive. Meningiomas arise from arachnoid cap cells, not glia, so no Grade 4 equivalent exists.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.