Background: The prevalence of incidental pituitary adenoma is estimated between 10 and 20% in autopsy and radiological data. Such pituitary incidentalomas are increasingly detected, as access to sensitive imaging modalities improves. We present a review of the recent pituitary incidentaloma referrals at a tertiary centre during 2 years from January 2013.
Methods: All patients with pituitary incidentalomas on brain imaging between 2013 and 2015 were reviewed. The referral source, original indication for imaging, MRI scan findings, visual fields, pituitary function, management decisions, and outcomes were analysed.
Results: Twenty-nine cases, age ranging from 17 to 75 (mean 48), were identified. 18 were females (62%) and 11 males (38%). Neurology accounted for 13 referrals (45%) with headache dominating the indications for MRI scan (10/29; 35%). 10/29 (35%) were macroadenomas (≥10 mm). Surgery was recommended for 5/10 (50%) due to tumour size and involvement of optic apparatus or the cavernous sinus. Four underwent surgery but one patient declined. Immunohistochemistry of the four samples showed mixed GH/ACTH adenoma, gonadotrophinoma, prolactinoma and null-cell adenoma. Three had visual field deficit. Two had at least two pituitary axes affected. 19/29 (65%) were microadenomas (<10 mm), all with normal pituitary function. In one patient, tumour size increased over a year, indicating future need for surgery. Normal pituitary gland was revealed on repeat dedicated pituitary MRI in four cases.
Conclusion: Pituitary incidentaloma is an increasingly common clinical entity. Significant proportion requires surgical intervention over time and it is important that patients are counselled appropriately. In addition, some incidentalomas may be secretory tumours as in our case. On the other hand, false-positive results from non-dedicated brain imaging may cause unnecessary anxiety. Careful evaluation by a pituitary MDT is essential to distinguish clinically significant tumours. A robust pathway including dynamic visual field, pituitary function and dedicated pituitary MRI should be part of such evaluation.