Prolactinoma

Question 1

Define Prolactinoma

Answer 1

Benign lactotroph adenomas expressing and secreting prolactin

Micro-adenoma <10mm (rarely increase in size)
Macro-adenoma >10mm (usually locally invasive into suprasella regions)

Hyperprolactinaemia = excess circulating prolactin NOT due to a physiological cause

Question 2

Aetiology and risk factors of Prolactinoma

Answer 2

Majority are sporadic
Associated with MEN-1 or FIPA (familial isolate pituitary adenoma)
Physiological: pregnancy
Pituitary adenomas that compress the stalk and prevent dopamine from suppressing prolactin -> hypersecretion
PCOS

RF:
Female 
20-50
MEN-1, FIPA 
Oestrogen therapy

Question 3

Epidemiology of Prolactinoma

Answer 3

Most common type of pituitary adenoma (40%)

More frequent in women during child-bearing years

Question 4

Symptoms of Prolactinoma

Answer 4

Amenorrhoea/oligomenorrhoea 
Infertility 
Galactorrhoea
Loss of libido 
Erectile dysfunction
Visual deterioration (Hemianopia)
Osteoporosis
Ophthalmoplegia
Headaches (pituitary apoplexy)

Question 5

Signs of Prolactinoma

Answer 5

Ophthalmoplegia

Bitemporal hemianopia

Question 6

Investigations for Prolactinoma

Answer 6

Visual field exam: may show hemianopia
Pregnancy test: exclude

Serum prolactin: elevated

Pituitary MRI: pituitary adenoma

Question 7

Management of Prolactinoma in pre- and post-menopausal women

Answer 7

Pre-menopause
Asymptomatic - observation

Symptomatic:

1. Dopamine agonist e.g. cabergoline PO
2. No desire to be pregnant - COCP
3. Trans-sphenoidl surgery
4. Sellar radiotherapy

Post-menopausal
Micro adenoma - observation
Macro adenoma - symptomatic pre-menopausal management

Question 8

Complications of Prolactinoma

Answer 8

Visual field impairment 
Anterior pituitary failure
Diabetes insipidus 
Pituitary apoplexy 
Cerebrospinal fluid leakage 
Radiotherapy -> hypopituitarism

Question 9

Prognosis for Prolactinoma

Answer 9

Progressive improving course with treatment
Continuous dopamine agonists - prolactin normalisation, tumour shrinkage + disappearance and rapid visual improvement
Can withdraw the dopamine agonist after several years with no tumour recurrence