Invasive Pituitary Adenoma
- Prolactin serum level guidelines: < 20- normal, 150-200- almost always due to adenoma, > 500- almost always due to large adenomas, > 1000- almost always related to invasion of adjacent structures particularly the cavernous sinuses
- Most invasive adenomas are not carcinomas; pituitary carcinomas are rare and associated with underlying corticotropin or prolactin secreting tumors; surgical cure is usually not possible if tumors had invaded the cavernous sinuses
- Pituitary carcinomas may give rise to local (CSF) or systemic metastases while invasive adenomas do not.
- Most invasive adenomas show higher cell proliferation as evidenced by high KI-67.
