Prolactinoma

Question 1

Definition

Answer 1

A pituitary adenoma that overproduces prolactin

Question 2

Aetiology

Answer 2

· There are different types of prolactinoma
o Microadenomas: < 1 cm
o Macroadenomas: > 1 cm
o Giant Pituitary Adenomas: > 4 cm
o Malignant Prolactinoma (RARE)

· Cause if UNKNOWN

· Some may occur as a consequence of MEN 1 syndrome

Question 3

Risk factors

Answer 3

o Risk of tumour enlargement in pregnancy

Question 4

Epidemiology

Answer 4

· Relatively common

· Higher incidence in premenopausal women

Question 5

Presenting symptoms (female)

Answer 5

o Amenorrhoea/oligomenorrhoea
o Galactorrhoea
o Infertility
o Hirsuitism
o Reduced libido

Question 6

Presenting symptoms (male)

Answer 6

o Symptoms are subtle and develop slowly
o Reduced libido
o Reduced beard growth
o Erectile dysfunction

Question 7

Presenting symptoms (symptoms by size)

Answer 7

NOTE: microprolactinomas rarely expand to become macroprolactinomas

Symptoms caused by tumour size:
o Headache
o Visual disturbance (bitemporal hemianopia)
o Cranial nerve palsies
o Signs and symptoms of hypopituitarism

Question 8

Investigations

Answer 8

· Exclude pregnancy

· TFTs - hypothyroidism –> high TRH –> stimulates prolactin release

· Serum prolactin level (extremely high levels (> 5000 mU/L) suggests true prolactinoma)

· MRI

· Assessment of pituitary function

Question 9

Management plan

Answer 9

· Goals
o Treat cause
o Relieve symptoms
o Prevent complications
o Restore fertility

· Dopamine Agonists (e.g. cabergoline and bromocriptine)
o Effective in most patients
o Usually need to be continued on a long-term basis

· If dopamine agonists are ineffective:
o Surgery
o Radiotherapy

Question 10

Possible complications

Answer 10

· Complications of hypogonadism
o Osteoporosis
o Reduced fertility
o Erectile dysfunction

· Complications of tumour size
o Visual loss
o Headache
o Pituitary apoplexy
o CSF rhinorrhoea

Question 11

Prognosis

Answer 11

· Microprolactinomas will spontaneously resolve in about 1/3 cases

· Dopamine agonist withdrawal is usually attempted after about 2-3 years if prolactin levels have normalised and tumour volume is reduced

· High rates of recurrence