Non-Functioning Tumours and Pituitary Hormone Testing

Question 1

Give examples of pituitary mass lesions

Answer 1

• Non-Functioning Pituitary Adenomas (silent)
• Endocrine active pituitary adenomas
• Malignant pituitary tumors: Functional and non-functional pituitary carcinoma
• Metastases in the pituitary (breast, lung, stomach, kidney)
• Pituitary cysts: Rathke’s cleft cyst, Mucocoeles, Others

Question 2

What is Rathke’s pouch?

Answer 2

• an evagination at the roof of the developing mouth in front of the buccopharyngeal membrane
• gives rise to the anterior pituitary

Question 3

What is a craniopharyngioma?

Answer 3

Developmental abnormality
Arise from squamous epithelial remnants of Rathke’s pouch

Question 4

What are features of a craniopharyngioma?

Answer 4

• Benign tumour although infiltrates surrounding structures
• Peak ages: 5 to 14 years; 50 to 74 years
• Solid, cystic, mixed, extends into suprasellar region

Question 5

What is Rathke’s cyst?

Answer 5

• Derived from remnants of Rathke’s pouch
• Single layer of epithelial cells with mucoid, cellular, or serous components in cyst fluid
• Mostly intrasellar component, may extend into parasellar area
• Mostly asymptomatic and small
• Present with headache and amenorrhoea, hypopituitarism and hydrocephalus

Question 6

What is a meningioma?

Answer 6

• Commonest tumour of region after pituitary adenoma
• Complication of radiotherapy
• Associated with visual disturbance and endocrine dysfunction
• Usually present with loss of visual acuity, endocrine dysfunction and visual field defects

Question 7

What are features of Non-Functioning Pituitary Adenomas (NFPA)?

Answer 7

• Pituitary adenomas account for 10-15% of primary intracranial tumours
• 50% of macroadenomas have visual disturbances and 50% have headaches

Question 8

What are signs of aggressiveness in NFPAs?

Answer 8

o Large size
o Cavernous sinus invasion
o Lobulated suprasellar margins

Question 9

What are features of Silent Pituitary Adenomas (SPA)?

Answer 9

• Most SPA express gonadotropins or subunits - Postop
• 23% of SPA are classified as null cell adenomas

Question 10

What are non-functioning tumours?

Answer 10

• No specific test but absence of hormone secretion
• Test normal pituitary function
• Trans-sphenoidal surgery if threatening eyesight or progressively increasing in size

Question 11

Why is testing pituitary function complex?

Answer 11

• Many hormones: GH, LH/FSH, ACTH, TSH and ADH
• May have deficiency of one or all and may be borderline
• Circadian rhythms and pulsatile

Question 12

What is the general indicator the pituitary is working?

Answer 12

If the peripheral target organ is working normally the pituitary is working

Question 13

What does a GH deficiency lead to?

Answer 13

• Short stature
• Abnormal body composition
• Reduced muscle mass
• Poor QoL
  Rx: GH

Question 14

What does an LH, FSH deficiency lead to?

Answer 14

• Hypogonadism
• Reduced sperm count
• Infertility
• Menstruation problems
  Rx: testosterone in males, oestradiol with or without testosterone in females

Question 15

What does a TSH deficiency lead to?

Answer 15

Hypothyroidism
Rx: Levothyroxine

Question 16

What does an ACTH deficiency lead to?

Answer 16

• Adrenal failure
• Decreased pigment
  Rx: Hydrocortisone

Question 17

What does an ADH deficiency lead to?

Answer 17

• Diabetes insipidus (ADH deficiency: less water absorption in kidney -> polyuria and polydipsia
  Rx: DDAVP