Pituitary Tumours (non-functioning)

Question 1

Define pituitary tumour

Answer 1

Clinically Non-Functional Pituitary Adenomas (CNFPAs) are pituitary adenomas that do not cause a characteristic hormone hypersecretion syndrome. They arise from null cell adenomas and the majority of gonadotroph adenomas.

Microadenoma: tumour size <1 cm.

Macroadenoma: tumour size ≥1 cm.

Question 2

What are the causes/risk factors of pituitary tumour?

Answer 2

The aetiology of pituitary adenomas is unknown. It is due to a genetic mutation that leads to the transformation of a normal pituitary cell into an adenoma. Hypothalamic hormones and other local growth factors may have an important role in promoting the growth of already transformed pituitary cell clones and also the expansion of small adenomas into large or invasive tumours. OP-1

Question 3

What are the symptoms of pituitary tumour?

Answer 3

• Pituitary adenomas may be asymptomatic and can be found incidentally on imaging –incidentalomas.
• Headaches
• Diplopia due to impingement of CN III, IV and VI in the cavernous sinus.
• Facial pain and paraesthesia due to impingement of CN V1 and V2 in the cavernous sinus.
• Symptoms of hypopituitarism since CNFPAs can grow to impinge on the APG, causing hyposecretion of the pituitary hormones. ation

Question 4

What are the signs of pituitary tumours?

Answer 4

• bitemporal hemianopia due to compression of optic nerve
• Cranial nerve palsies involving third, fourth, fifth (V1 and V2), and sixth cranial nerves and mydriasis associated with third nerve palsy may be present.
• Clinical features of hypopituitarism.

Question 5

What investigations are carried out for pituitary tumours?

Answer 5

• Pituitary MRI (or CT if MRI contraindicated) - these show a sellar mass: a mass in the sella turcica.
• Visual Field Testing –Perimetry: These show Bitemporal hemianopia.
- Humphrey Perimetry
- Goldmann Perimetry
• Endocrine Function Tests for Hypopituitarism.