Table 2.
Main histopathological features of the BCOR‐ITD tumours
| Number of cases | Histological pattern | Cytology | Pseudorosettes | Microcystic background | Haemorrhage | Calcification | Necrosis | Mitotic count per 10 hpf | |
|---|---|---|---|---|---|---|---|---|---|
| CNS BCOR‐ITD | 9 |
EPN‐like (6/9) Fascicular (3/9) |
Spindle cells | 9/9 | 7/9 | 6/9 | 2/9 | Palisading, geographic and calcified (6/9) | 5–62 |
| URCS | 6 |
Fascicular Diffuse |
Round‐to‐ovoid, spindle cells | 1/6 | 0 | 4/6 | 0 | 0 | 1.7–13.7 |
| HG‐ESS | 2 | Diffuse | Spindle cells | 1/2 | 2/2 | 2/2 | 0 | 0 | 14–21 |
| CCSK | 4 |
Diffuse Alveolar |
Round‐to‐ovoid, spindle cells | 0 | 1/4 | 0 | 0 | 0 | 0–18 |
EPN, ependymoma; hpf, high‐power field.