Pituitary Tumours

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management

Definition

Pituitary tumours are abnormal growths within the pituitary gland, which can be benign (adenomas) or, rarely, malignant. They may result in hormone overproduction, hormone deficiency, or mass effects due to compression of nearby structures.

Aetiology

  • Genetic predisposition: associated with syndromes like multiple endocrine neoplasia type 1 (MEN1).
  • Spontaneous mutations: leading to abnormal pituitary cell proliferation.
  • Hormonal stimulation: chronic overstimulation of pituitary cells contributing to tumour formation.

Pathophysiology

  • Pituitary tumours can be functioning (hormone-secreting) or non-functioning (non-secretory).
  • Functioning tumours lead to excess hormone production, causing conditions such as acromegaly (GH excess), Cushing’s disease (ACTH excess), or prolactinoma (prolactin excess).
  • Non-functioning tumours often present with compressive symptoms due to mass effect.
  • Compression of the optic chiasm can result in bitemporal hemianopia.
  • Compression of normal pituitary tissue may lead to hypopituitarism.

Risk Factors

  • Family history of pituitary disorders.
  • Genetic syndromes such as MEN1.
  • Previous radiation exposure to the head.

Signs and Symptoms

  • Mass effect symptoms:
    • Headaches.
    • Visual field defects (bitemporal hemianopia).
    • CN III, IV, VI palsies in large tumours compressing the cavernous sinus.
  • Hormonal excess:
    • Hyperprolactinaemia: galactorrhoea, amenorrhoea, infertility.
    • GH excess: acromegaly (adults), gigantism (children).
    • ACTH excess: Cushing’s disease (moon face, central obesity, purple striae).
  • Hormonal deficiency:
    • Hypopituitarism: fatigue, weight loss, cold intolerance, hypotension.

Investigations

  • Hormonal assays: prolactin, GH, IGF-1, ACTH, cortisol, LH, FSH, TSH.
  • Visual field testing: to assess for bitemporal hemianopia.
  • Pituitary MRI: imaging to confirm presence and size of the tumour.

Management

Note: The following information is for awareness only, as management is carried out by a specialist/MDT.

1. Medical Management:

  • Prolactinomas: dopamine agonists (e.g., cabergoline, bromocriptine).
  • Acromegaly: somatostatin analogues (e.g., octreotide), GH receptor antagonists.
  • Cushing’s disease: steroidogenesis inhibitors (e.g., ketoconazole, metyrapone).

2. Surgical Management:

  • Transsphenoidal surgery: first-line treatment for large or symptomatic tumours.
  • Craniotomy: for larger or invasive tumours.

3. Radiotherapy:

  • Considered in refractory cases or when surgery is contraindicated.
EndocrinologymypanotesPituitary Tumours