TABLE 2.
N (%) | ||
---|---|---|
Grade II Oligodendroglioma (N=38) | Grade III Oligodendroglioma (N=12) | |
Round nuclei | 38 (100) | 12 (100) |
Perinuclear halos | 38 (100) | 12 (100) |
Microcysts | 14 (44) | 4 (40) |
Microcalcifications | 15 (48) | 4 (40) |
Secondary structures | 3 (91) | 6 (75) |
Leptomeningeal extension | 3 (10) | 0 |
Nodular architecture | 2 (6) | 1 (10) |
Cortical involvement | 27 (90) | 6 (60) |
Minigemistocytes | 3 (9) | 1 (10) |
Gliofibrillary oligodendrocytes | 0 | 1 (10) |
Microvascular changes | 1 (3) | 7 (70) |
Necrosis | 1 (3) | 3 (30) |
GFAP expression | ||
Positive | 1 (17) | 0 |
Focal | 2 (33) | 0 |
S100 expression | ||
Positive | 3 (100) | NA |
Synaptophysin expression | ||
Positive | 1 (13) | 1 (17) |
Strong p53 immunostaining | 0 | 1 (14) |
IDH1 (R132H) | ||
Positive | 3 (19) | 1 (17) |
1p19q | ||
Codeletion | 6 (21) | 4 (36) |
1p loss only | 0 | 1 (9) |
1p19q intact | 23 (79) | 6 (55) |