Endocrine Abstracts

Non-functioning pituitary adenomas (NFAs) are benign pituitary neoplasms arising from the adenohypophyseal cells. They are not associated with clinical evidence of hormonal hypersecretion and have a prevalence of 22 cases/100 000 people. They are diagnosed more commonly in males (2/3 of the NFA cases) and based on a recent UK community-based cross-sectional study, the median age at their diagnosis is 52 years (males 51 and females 43). At presentation, the majority is macroadenomas and their clinical manifestations are the result of pressure effects to surrounding structures.

Studies assessing the natural history of presumed, non-operated NFAs have shown probability of enlargement 19% for microadenomas and 44% for macroadenomas at 48 months follow-up. It has also been proposed that the event rate for growth per 100 patient-years is 12.53 (95% CI: 7.86–17.20) for macroadenomas and 3.32 (95% CI: 2.13–4.50) for microadenomas, whereas the risk of apoplexy is low. Factors predicting the behaviour of this group of NFAs are not clear.

Surgery remains the main management option for patients with macroadenomas exerting pressure effects to vital structures. Relapse rates in those treated only by surgery range between 6–46% (the risk is higher if there is extrasellar tumour remnant) and in those managed by surgery and adjuvant radiotherapy between 0–36%. Up to 20% of the relapses have been detected 10 years post-operatively necessitating long-term surveillance. Careful monitoring is also required for patients who had surgery following apoplexy of their NFA, as the risk of regrowth is not minimal (13% at 60 months). Reliable markers of tumour relapse at a pathological and/or molecular level are currently lacking.