During the past several years the wide application of sensitive brain imaging techniques (CT, MRI) has led to an increasing recognition of asymptomatic lesions in the pituitary. Although their etiology covers a wide range of pathologies, most incidentally discovered pituitary lesions are benign adenomas, ranging in size from micro- (<10 mm) to macro- (>10 mm) adenomas. Micro-incidentalomas are very common, with a reported incidence in normal individuals of 420%. Although the identification of such lesions raises the theoretical risk of hormonal hypersecretion further screening confers minimal benefit and may not be cost-effective. Although, in the absence of clinical stigmata of Cushings disease or acromegaly, only the measurement of prolactin represents a cost-effective strategy, recent guidelines suggest that a broader hormonal investigation may be more widely recommended. MRI follow-up of micro-incidentalomas is expensive. Since the majority of micro-incidentalomas do not increase in size during follow-up, the suggested need for routine application of repeat scans needs careful evaluation. At variance with pituitary micro-incidentalomas, the incidental discovery of a macro-lesion requires extensive investigation. Most, but not all, macro-incidentalomas demonstrate radiological features consistent of pituitary adenomas. If the lesion causes hypersecretion of prolactin, GH or ACTH, specific therapy is required. If the lesion compresses the optic chiasm, and there is no evidence of prolactin hyperseceretion, surgical removal is obviously indicated. If no hormonal hypersecretion is found, and if the lesion is in some distance from the optic chiasm, routine surgical removal may not be necessary. Indeed, not all tumors demonstrate a significant increase in size requiring surgical excision. Thus expectant management is a safe option for many patients, given that regular MRI surveillance is recommended. Evaluation for anterior pituitary hormone deficiencies is required in all patients with macro-lesions and, hormone replacement therapy should be offered as required.
Declaration of interest: The author declares that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.