Pituitary Tumours

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

Definition

Pituitary tumours are abnormal growths that develop in the pituitary gland, a small gland located at the base of the brain. These tumours can be benign (non-cancerous) or, rarely, malignant (cancerous) and can affect hormone production, leading to various clinical syndromes.

Aetiology

The exact cause of pituitary tumours is often unknown. However, genetic factors and familial syndromes can play a role:

• Sporadic Tumours: Most pituitary tumours occur sporadically without a clear cause.
• Genetic Syndromes: Conditions such as Multiple Endocrine Neoplasia type 1 (MEN1), Carney complex, and familial isolated pituitary adenoma (FIPA) are associated with an increased risk of developing pituitary tumours.

Pathophysiology

Pituitary tumours can be classified based on their hormone secretion and size:

• Functioning Tumours: These tumours secrete excess hormones, leading to clinical syndromes such as Cushing’s disease (ACTH-producing), acromegaly (GH-producing), and prolactinoma (prolactin-producing).
• Non-functioning Tumours: These do not secrete hormones but can cause symptoms by compressing adjacent structures.
• Microadenomas: Tumours less than 10 mm in size.
• Macroadenomas: Tumours greater than 10 mm in size.

Risk Factors

• Family history of pituitary tumours or related genetic syndromes
• Genetic mutations (e.g., MEN1 gene mutations)
• Age (most common in adults aged 30-60)
• Female gender (for certain types like prolactinomas)

Signs and Symptoms

Symptoms of pituitary tumours can vary depending on the type and size of the tumour:

• Functioning Tumours:
  • Prolactinoma: Galactorrhoea, menstrual disturbances, infertility in women, erectile dysfunction in men.
  • GH-producing Tumours: Acromegaly in adults (enlarged hands and feet, coarse facial features), gigantism in children (excessive growth).
  • ACTH-producing Tumours: Cushing’s disease (weight gain, hypertension, glucose intolerance).
  • TSH-producing Tumours: Hyperthyroidism (weight loss, palpitations, heat intolerance).
• Non-functioning Tumours:
  • Headaches
  • Visual disturbances (due to compression of the optic chiasm)
  • Hypopituitarism (fatigue, weakness, decreased libido, infertility)

Investigations

• Clinical history and physical examination
• Hormonal assays: Serum levels of prolactin, GH, IGF-1, ACTH, cortisol, TSH, free T4, LH, FSH, and testosterone/estradiol
• Magnetic resonance imaging (MRI): To visualise the pituitary gland and assess the size and extent of the tumour
• Visual field testing: To assess for visual deficits due to optic chiasm compression
• Dexamethasone suppression test or 24-hour urinary free cortisol: For diagnosing Cushing’s disease
• Glucose tolerance test with GH measurement: For diagnosing acromegaly

Management

Primary Care Management

• Referral to endocrinologist: For diagnosis confirmation and management plan
• Monitoring: Regular follow-up for patients with known pituitary tumours to monitor for changes in size or function
• Education: Informing patients about the condition, potential symptoms, and the importance of follow-up

Specialist Management

• Surgery: Transsphenoidal surgery for tumour resection, especially for large or symptomatic tumours
• Medical therapy:
  • Dopamine agonists (e.g., cabergoline, bromocriptine) for prolactinomas
  • Somatostatin analogues (e.g., octreotide, lanreotide) and GH receptor antagonists (e.g., pegvisomant) for acromegaly
  • Adrenal enzyme inhibitors (e.g., ketoconazole, metyrapone) for Cushing’s disease
• Radiotherapy: For residual or recurrent tumours post-surgery, or for non-resectable tumours
• Hormone replacement therapy: For patients with hypopituitarism to replace deficient hormones (e.g., cortisol, thyroid hormone, sex hormones)
• Management of complications: Addressing issues such as diabetes, hypertension, and osteoporosis in patients with functioning tumours

Example Management for Pituitary Tumours

A patient diagnosed with a prolactinoma presenting with galactorrhoea and menstrual disturbances should be referred to an endocrinologist. Initial management includes medical therapy with dopamine agonists (e.g., cabergoline) to reduce prolactin levels and tumour size. If the tumour is large or unresponsive to medical therapy, surgical resection may be considered. Regular monitoring of prolactin levels and MRI scans are essential to assess the effectiveness of treatment and detect any recurrence. The patient should be educated on the importance of medication adherence and regular follow-up.

References

1. NICE. (2024). Pituitary Tumours: Diagnosis and Management. Retrieved from NICE
2. NHS. (2023). Pituitary Tumours. Retrieved from NHS
3. British Society of Endocrinology. (2022). Guidelines for the Management of Pituitary Tumours. Retrieved from British Society of Endocrinology
4. American Association of Clinical Endocrinologists (AACE). (2021). Clinical Practice Guidelines for the Diagnosis and Management of Pituitary Tumours. Retrieved from AACE

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