Pituitary tumors are classified as micoradenomas, sometimes called incidentalomas, because they tend to be asymptomatic and discovered incidentally, or macroadenomas. Microadenomas are small and macroadenomas are larger. BMJ Best Practice (2012) says that there is no consensus about the follow-up duration of patients with non-functional pituitary microadenomas, but recommends a follow-up MRI in 1 year with no further routine imaging study if the tumour is stable, especially in those with a pituitary microadenoma < 6 mm in size, unless the patient develops symptoms or signs suggestive of mass effect.
The risk of tumour growth for pituitary macroadenomas is expected to be higher since the tumour has already shown the propensity to grow. There is no consensus, but a pragmatic approach would be to obtain a follow-up MRI at 6 months and then yearly for 5 years. This can be followed by an imaging study every 2 to 3 years if the pituitary tumor is stable. This recommendation is in line with that of the Endocrine Society and Best Practice.
Biochechemical and laboratory followup is not discussed in this review of radiologic followup.
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