Pituitary incidentalomas: A guide to assessment, treatment and follow-up

Pituitary incidentalomas are lesions which are detected incidentally in the pituitary gland during imaging procedures for unrelated causes, such as headache, trauma or symptoms involving the neck or central nervous system. The wide application of sensitive brain imaging techniques (CT, MRI) has led to an increasing recognition of such lesions. Although the etiology of pituitary incidentalomas covers a wide range of pathologies, most of them (∼90%) are benign adenomas; nonetheless, they may result in visual and/or neurologic abnormalities. By definition, micro-incidentalomas have maximum diameter of less than 1cm, while macro-incidentalomas are at least 1cm. Micro-incidentalomas have a reported mean prevalence in normal individuals of around 10%. The endocrinologist facing a pituitary incidentaloma has to solve two main diagnostic problems: (i) the nature and extent of the lesion, and (ii) whether hormonal excess or deficits result from the lesion. The former is achieved by the use of pituitary MRI and visual field (VF) examination and the latter by basal or dynamic hormonal assessments. The answers to these two questions will guide the treatment and follow-up. VF deficits or neurological disturbances due to compression of the optic chiasm or nerve by the incidentaloma are the strongest recommendations for surgery. Furthermore, hormonally active incidentalomas, with the exception of prolactinomas, should be treated by surgery. Most cases of pituitary incidentalomas do not meet criteria for surgical excision, but may require follow-up. The follow-up strategy consists of clinical evaluation, pituitary MRI, VF examination and hormonal assessments. Macro-incidentalomas require more extensive initial investigation, as well as closer MRI surveillance, than micro-incidentalomas. Diagnostic, treatment and follow-up strategies should be in alignment with the optimal personalized clinical benefit.