The frequent use of brain and head MRI/CT has lead to an increase in the number of incidental pituitary lesions reported, so called pituitary incidentalomas. Such lesions require endocrine evaluation of pituitary function and radiological follow up. We performed a retrospective study to examine the source of these referrals, size of the incidentalomas, frequency of pituitary dysfunction and changes during follow-up. We performed a search of the departmental endocrine database and clinical letters for the term incidentaloma from 2005 onwards.
Thirty six patients, age ranged 2386 years, F 22:M14 were identified with pituitary incidentalomas. The majority of referrals were from the departments of neurology and ophthalmology, to a lesser extent from general practitioners, elderly care and psychiatry. Of these 36 pituitary incidentalomas, there were 18 macroadenomas, 14 microadenomas, 3 pituitary hyperplasia and 1 intrasellar meningioma.
Following endocrine evaluation, hypopituitarism was rare and found in only one macroadenoma and not in any microadenomas. Hypersecretion was also infrequent; 1/18 macroadenomas secreting prolactin. Three microadenomas were secreting excess hormones; 2/14 prolactin, 1/14 growth hormone. The optic chiasm was radiologically involved in 7/18 macroadenomas; however visual fields were affected in only 2/18. Of those patients who did not undergo surgery (n=22), radiological follow up in the remainder, confirmed an increase in tumour size in 2/10 macroadenomas and 1/12 microadenomas.
We conclude that pituitary dysfunction is uncommon in pituitary incidentalomas, which may explain why these lesions are found incidentally even though the majority of these are macroadenomas.