Tumor classification according to Wigand
| Stage | Tumor size |
| A | Limited to the internal auditory canal and tumor size (mean diameter) of 1-8 mm |
| B | Extension to the cerebellopontine angle and tumor size of 9-25 mm. |
| C | Contact with the brainstem and tumor size > 25 mm. |
Tumor classes according to Samii
| Tumor class | Description |
| T1 | Purely intrameatal tumor (in the bony ear canal) |
| T2 | Intra- and extrameatal tumor portion (inside and outside the bony auditory canal) |
| T3a | Tumor fills cerebello-pontine cistern (between cerebellum and brainstem) |
| T3b | Tumor reaches the brain stem |
| T4 | Tumor compresses the brainstem |
| T4b | Tumor compresses the brainstem and displaces the fourth ventricle (cerebral ventricle) |
