Nonfunctioning pituitary tumors

Clinically nonfunctioning adenomas range from being completely asymptomatic, and therefore detected either at autopsy or as incidental findings on head MRI or CT scans performed for other reasons, to causing significant hypothalamic/pituitary dysfunction and visual field compromise due to their large size. Patients with incidental adenomas should be screened for hypersecretion (prolactin, insulin-like growth factor 1, midnight salivary cortisol) and for hypopituitarism (macroadenomas). In the absence of hypersecretion, hypopituitarism, or visual field defects, patients may be followed by periodic screening by MRI for enlargement, at which point surgery may be necessary. Symptomatic patients with clinically nonfunctioning adenomas are generally treated by transsphenoidal surgery. Postoperative MRIs are done at 3-4 months after surgery to assess for completeness of resection and then repeated yearly for 3-5 years and subsequently less frequently to assess for regrowth. For those with no visible tumor on MRI, the tumor regrowth rate is about 13% and such patients may be followed with periodic MRIs. For those with visible tumor, the tumor regrowth rate is about 40%. This regrowth rate may be substantially reduced with the use of dopamine agonists and radiotherapy.