What is the appropriate workup for a pituitary adenoma?

From the Guidelines

The initial workup for a suspected pituitary adenoma should include a dedicated pituitary MRI with pre-contrast (T1 and T2) and post-contrast-enhanced (T1) thin-sliced sequences, as it is the imaging investigation of choice 1. This approach is based on the most recent consensus guideline for the diagnosis and management of pituitary adenomas 1. The standard pituitary protocol can be supplemented by a volumetric (gradient recalled echo) acquisition after contrast, which may improve the sensitivity for adenoma detection 1.

Key components of the pituitary adenoma workup include:

• A thorough clinical assessment, including a detailed history of symptoms such as headaches, visual disturbances, menstrual irregularities, galactorrhea, decreased libido, or signs of hormone excess or deficiency
• Laboratory testing with a comprehensive pituitary hormone panel: prolactin, growth hormone with IGF-1, ACTH, cortisol, TSH, free T4, LH, FSH, testosterone (in men), and estradiol (in women)
• MRI of the pituitary with and without contrast, using thin-slice (1-3mm) sections through the sella turcica to accurately characterize the size, location, and relationship of the adenoma to surrounding structures 1
• Consideration of 3-Tesla MRI for surgical planning or intra-operative MRI, as it enhances anatomical definition and might improve completeness of resection without altering complication rates 1
• Visual field testing if the tumor is near the optic chiasm
• Specific dynamic testing for functioning adenomas, such as an oral glucose tolerance test for acromegaly or dexamethasone suppression testing for Cushing's disease

In patients with suspected pituitary adenoma where MRI is negative or equivocal, molecular (functional) imaging might aid neoplasm localization, using hybrid imaging techniques such as PET–CT co-registered with MRI or PET–MRI 1. A multidisciplinary approach involving endocrinology, neurosurgery, and sometimes radiation oncology is recommended for optimal management 1.

From the Research

Pituitary Adenoma Workup

• The workup for pituitary adenomas involves evaluating complete pituitary function, as hypopituitarism is common 2
• Patients with macroadenomas require evaluation for hypopituitarism, and those with tumors compressing the optic chiasm should undergo formal visual field testing 3
• The primary treatment for prolactinomas is dopamine agonists, such as cabergoline and bromocriptine 4, 3, 2
• For other pituitary adenomas, initial therapy is generally transsphenoidal surgery, with medical therapy reserved for those not cured by surgery 4, 3

Diagnostic Approach

• The diagnosis of pituitary adenomas may be made based on symptoms of endocrine dysfunction, such as infertility, decreased libido, and galactorrhea, or with neurologic symptoms like headache and visual changes 2
• Imaging studies, such as MRI, may also be used to diagnose pituitary adenomas, particularly in asymptomatic patients with incidentalomas 2
• Hormone level testing, including prolactin, growth hormone, and adrenocorticotropic hormone (ACTH), is essential in the diagnostic workup of pituitary adenomas 4, 3, 5

Treatment Options

• Transsphenoidal surgery is the primary treatment for most pituitary adenomas, except for prolactinomas, which are typically treated with medical therapy 4, 3
• Medical therapy, including somatostatin analogues, cabergoline, and pegvisomant, may be used in conjunction with surgery or as an alternative to surgery in some cases 4, 3
• Radiotherapy may also be used in some cases, particularly for residual or recurrent tumors 4

Specific Types of Pituitary Adenomas

• Prolactinomas account for 32-66% of pituitary adenomas and are typically treated with dopamine agonists 4, 3
• Growth hormone-secreting tumors account for 8-16% of pituitary adenomas and are usually treated with surgery and medical therapy, including somatostatin analogues and pegvisomant 4, 3
• ACTH-secreting tumors account for 2-6% of pituitary adenomas and are associated with Cushing disease, which is typically treated with surgery and medical therapy, including ketoconazole and pasireotide 4, 3