Once tumours were categorised by their light microscopic appearance but now tumours are more reliably categorised by immunoperoxidase studies.
Blood tests for the hormones are important diagnostic tools.
CT scans, MRI and other imaging techniques are important for determining size (and seriousness of tumours), growth over time and treatment options.
Most tumours are benign but are quite serious because of their position close to important brain structures.
Treatment includes: