Clinically non-functional pituitary adenomas (CNFPAs) are considered here; functional pituitary adenomas (e.g., acromegaly, Cushing's syndrome, prolactinoma) are dealt with separately.
Small pituitary tumours (<4 mm) are common and have been reported in up to 10% of MRIs in the general population. Only a small fraction of such tumours are associated with clinical features suggestive of pituitary disorder.
Radiologically, CNFPAs are classified as micro-adenomas (<1 cm diameter) or macro-adenomas (≥1 cm diameter); they may have suprasellar extension towards the optic chiasm, lateral extension into the cavernous sinuses, or downward extension into the sphenoid.
Patients with non-functional pituitary micro-adenomas require limited follow-up, but pituitary macro-adenomas need to be followed for life.
Non-functional pituitary macro-adenomas typically come to medical attention with features of mass effect such as headaches, visual field deficits, hypopituitarism, and rarely cranial nerve palsies.
A modest elevation of prolactin may occur in CNFPAs due to compression of the pituitary stalk and interruption of intrinsic dopaminergic tone.
Trans-sphenoidal surgery is the first-line therapy for patients with CNFPAs and mass effect.
Pituitary adenomas are the third most common intra-cranial neoplasms in adults, accounting for about 10% of all intra-cranial tumours. They are diagnosed when patients present with hormone hypersecretion, plus visual and neurological deficits and hypopituitarism as a result of mass effect. They may also be found as pituitary incidentalomas. Pituitary adenomas that do not cause a characteristic hormone hypersecretion syndrome (null cell and the majority of gonadotroph adenomas) are referred to as clinically non-functional adenomas (CNFPAs). CNFPAs and prolactinomas are the 2 most prevalent pituitary adenomas. CNFPAs are considered here. Functional pituitary adenomas (e.g., acromegaly, Cushing's syndrome, prolactinoma) are not covered here.
History and exam
Key diagnostic factors
- presence of risk factors
- long-standing and progressing symptoms
- erectile dysfunction
- soft small testicles
- breast atrophy
- loss of libido
- hot flushes
- weight gain
- decreased visual acuity
- bitemporal hemianopia
- pituitary apoplexy
Other diagnostic factors
- increased central adiposity
- reduced muscle mass
- cold intolerance
- dry skin
- hair loss
- poor memory
- low mood
- weight loss
- facial numbness
- urinary incontinence
- recurrent sinusitis
- multiple endocrine neoplasia type 1 (MEN-1)
- familial isolated pituitary adenomas (FIPA)
- Carney complex (CNC)
1st investigations to order
- insulin-like growth factor 1
- luteinising hormone, follicle-stimulating hormone
- alpha subunit of human pituitary glycoprotein hormones
- thyroid-stimulating hormone, free thyroxine
- morning cortisol
- adrenocorticotrophic hormone (ACTH) stimulation test
- adrenocorticotrophic hormone
- insulin tolerance test for cortisol
- basic metabolic panel
- MRI pituitary with gadolinium enhancement
- contrast enhanced CT pituitary
Investigations to consider
- growth hormone stimulation test
- lipid panel
- Humphrey or Goldmann formal visual fields test
- immunohistochemical staining
macro-adenoma without mass effect and not abutting optic chiasm
macro-adenoma without mass effect but abutting optic chiasm
macro-adenoma with mass effect
- Prolactin-secreting adenoma (prolactinoma)
- Growth hormone-secreting adenoma (acromegaly)
- Adrenocorticotrophic hormone-secreting adenoma (Cushing syndrome)
- Suspected cancer: recognition and referral
- Hormonal replacement in hypopituitarism in adults: an Endocrine Society clinical practice guideline
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