Neurology of the pituitary gland

This review will focus on those aspects of pituitary diseaseimmediately relevant to neurologists and neurosurgeons when assessing and counselling patients. It is essential to adopt a multidisciplinary approach to the diagnosis and management of pituitary diseaseas emphasised by the recently published guidelines from the Royal College of Physicians of London.1-4 View this table: Differential diagnosis of neoplasms and “tumour-like” lesions of the sellar region2 The commonest lesions presenting in this region are pituitary tumours(incidence of 15–20/million/year), including adenomas and craniopharyngiomas, aneurysms, and meningiomas, but many other diseases need to be considered (table 1). ”Pituitary incidentalomas” may be disclosed when investigating unrelated disease (fig 1). Although figures from 5% to 27% have been quoted for the incidence of subclinical adenomas at postmortem, far fewer are of significant size—that is, over 5 mm in diameter with deviation of the stalk and unilateral enlargement of the gland. Careful endocrine and visual assessments are required and, where no abnormalities are found, most can be managed conservatively with follow up MRI.5-8 Figure 1 (A) Normal appearance of pituitary gland. Sagittal TI weighted image. Note the bright signal from the posterior lobe of the pituitary. More posteriorly the dorsum sella(arrow head) is shown as linear high signal (marrow) surrounded by low signal (dense cortex). (B) Microadenoma on the left side. This has a lower signal than normal pituitary. The normal pituitary and cavernous sinusshow enhancement after gadolinium injection. Pituitary diseaseoften presents insidiously and in retrospect might have been detected earlier. The symptoms of hormonal hypersecretion in endocrinologically active tumours will obviously present before evidence of suprasellar or parasellar extension. Although somatic changes usually bring the growth hormone secreting adenoma to medical attention first, the neurologist may encounter nerve entrapment (particularly the carpal tunnel syndrome), proximal myopathy (weakness disproportionate to the increased body …