1. Grade I. Meningothelial, fibrous (fibroblastic), transitional (mixed), psammomatous, angiomatous, microcystic, secretory, lymphoplasmacyte-rich, metaplastic |
2. Grade II. Chordoid, clear cell, atypical, brain-invasive |
3. Grade III. Papillary, rhabdoid, and anaplastic (malignant) |