The classification of stages varies from tumor type to tumor type.
Primary intracranial tumors
- Classification according to histological type and localization.
- TNM-classification is not used.
Pituitary gland tumors
- Tumor size is used for classification of pituitary gland adenomas.
- Microadenomas < 10 mm
- Macroadenomas ≥ 10 mm
- Knosp classification indicates lateral spread of pituitary gland tumors.
The Knosp classification is divided into stages from 0 to 4, where grade 0 is intrasellar tumors without spreading into cavernous sinus, and grade 4 are tumors which enclose the intracavernous part of the internal carotid artery. Tumors that spread laterally from the internal carotid artery are very difficult to remove radically.
- Metastases are classified according to the TNM classification.
- The TNM system describes how widespread the disease is at the time it is detected.