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) |