Table 3.
Main histological, immunohistochemical and molecular features of diffuse gliomas with FGFR3‐TACC3 fusion.
| Features | Diffuse gliomas with FGFR3‐TACC3 fusion |
|---|---|
| N | 30 |
| M:F | 1:1 |
| Mean age at diagnosis | 62y ±12 (range 42–87 y) |
| Resection/Biopsy | 21/9 (70%)/(30%) |
| Localization | |
| Right/left side | 18 (60%)/12 (40%) |
| Frontal | 10 (33%) |
| Temporal | 8 (27%) |
| Parieto‐occipital | 7 (23%) |
| Parietal | 3 (10%) |
| Temporo‐parietal | 1 (3%) |
| Fronto‐temporal | 1 (3%) |
| Tumor type | |
| Glioblastoma, IDH‐wildtype grade IV | 25 (83%) |
| Gliosarcoma, IDH‐wildtype grade IV | 1 (3%) |
| Glioblastoma, NOS grade IV | 1 (3%) |
| Diffuse astrocytoma, IDH‐wildtype grade II | 3 (10%) |
| Histological features | |
| Recurrent morphological features* | 22 (73%) |
| Monomorphous ovoid nuclei | 26 (87%) |
| Calcifications | 17 (57%) |
| Desmoplastic changes | 15 (50%) |
| Endocrinoid vascular network | 26 (87%) |
| Immunohistochemical features | |
| IDH1 R132H positivity | 0/28 (0%) |
| ATRX loss of expression | 0/28 (0%) |
| P53 | 4/28 (14%) |
| Mean Ki67 index grade II | 3% ±2 |
| Mean Ki67 index grade IV | 16% ±11 |
| CD34 | 16/29 (55%) |
| EGFR score (from 0 to 400) | 131 ± 93 (n = 29) |
| EMA | 16/29 (55%) |
| Molecular features | |
| IDH1 or IDH2 mutation | 0/28 (0%) |
| TERT promoter mutation | 17/23 (74%) |
| 1p/19q codeletion | 0/26 (0%) |
| 7p gain and 10q loss | 16/25 (64%) |
| 10q loss, 13q loss, 14q loss | 2/22 (9%) |
| EGFR amplification | 0/29 (0%) |
| MDM2 amplification | 5/26 (19%) |
| CDK4 amplification | 5/26 (10%) |
| P16 deletion | 11/26 (42%) |
* Recurrent morphological features are monomorphous ovoid nuclei, endocrinoid network of thin capillaries, nuclear palisading, attachment of tumor cells to vessels by equidistant thin parallel cytoplasmic processes producing vague pseudorosettes.