What is the natural history of nonfunctioning pituitary tumors?
The growth frequency of NFAs is estimated to be ≈ 10% to 13% for microadenomas and ≈ 34% to 40% for macroadenomas over 8 years. Progressive tumor growth usually proceeds at very slow rates (1–2 mm/year). Long term, microadenomas rarely grow to be > 1 cm in size. Lastly, the incidence of pituitary apoplexy is approximately 1.1 per 100 patient-years for macroadenomas and 0.4 per 100 patient-years for microadenomas.