Craniopharyngioma

Craniopharyngioma is a rare brain tumour derived from pituitary gland embryonic tissue. Although it can occur at any age, it is most common in children aged 5-14 and adults aged 50-74. It often presents with visual disturbances such as bitemporal inferior quadrantanopia progressing to bitemporal hemianopsia due to optic chiasm compression. The point prevalence is approximately two per 1,000,000.

Symptoms and Signs

Craniopharyngiomas are typically benign but can cause significant morbidity due to their location and treatment. Symptoms include:

• Headache: Often due to obstructive hydrocephalus.
• Hypersomnia: Excessive sleepiness.
• Myxedema: Severe hypothyroidism.
• Postsurgical Weight Gain: Hypothalamic obesity.
• Polydipsia and Polyuria: Indications of diabetes insipidus.
• Vision Loss: Bitemporal hemianopia.
• Vomiting: Common post-treatment.
• Growth Hormone (GH) Insufficiency: Stunted growth in children; fatigue and muscle loss in adults.
• Pituitary Insufficiency: Leading to hormone imbalances, including rare prolactin reduction.
• Diabetes Insipidus and Adrenal Insufficiency: Resulting in excessive urination and fatigue.

Mechanisms

Craniopharyngiomas develop from Rathke's pouch remnants, a precursor to the anterior pituitary. These tumours are typically slow-growing and often contain calcium deposits visible on X-rays.

Diagnosis

Imaging Scans

High-resolution MRI and CT scans are very important for diagnosis. CT scans remain the gold standard due to their ability to detect calcifications within the tumour.

Two distinct types are recognised:

• Adamantinomatous Craniopharyngiomas: Characterised by CTNNB1 mutations and visible calcifications.
• Papillary Craniopharyngiomas: Characterised by BRAFv600E mutations and rarely calcify.

Microscopically, craniopharyngiomas often show squamous epithelium with calcium deposits and cysts filled with cholesterol-rich fluid.

Treatment

The primary treatment is surgical excision, either by a subfrontal or transsphenoidal approach. Endoscopic surgery through the nose is an alternative, often performed by a team of neurosurgeons and ENT specialists. If total removal isn't possible, radiotherapy is commonly used.

Experimental therapies involving intracavitary phosphorus-32, yttrium, or bleomycin are being looked at, especially in younger patients. Proton therapy is also an option due to its precision and reduced impact on surrounding tissues.

Prognosis

Although generally benign, craniopharyngiomas can recur post-resection. Malignant transformations are rare but associated with a poor prognosis. The best treatment for malignant craniopharyngiomas involves gross total resection followed by chemoradiotherapy, although survival rates remain low.

Recent Research

Research focuses on less invasive treatments and methods to prevent obesity due to hypothalamic damage. Conservative surgery combined with radiotherapy is often favoured to minimise complications such as hypothalamic damage, which can lead to severe obesity. Modern radiotherapy techniques, including proton therapy, offer precise targeting while preserving surrounding tissues, achieving tumour control rates exceeding 90%.

---

Self-assessment MCQs (single best answer)

Craniopharyngioma is derived from which embryonic tissue?

What is the most common age range for craniopharyngioma occurrence in children?

Which symptom is commonly associated with optic chiasm compression in craniopharyngioma?

What type of imaging scan is considered the gold standard for detecting calcifications in craniopharyngiomas?

Which mutation is commonly seen in adamantinomatous craniopharyngiomas?

What type of cystic fluid is often found in craniopharyngiomas?

Which surgical approach is NOT commonly used for craniopharyngioma excision?

Which experimental therapy is being looked at for craniopharyngiomas, particularly in younger patients?

What is a major complication associated with hypothalamic damage in craniopharyngioma treatment?

What type of craniopharyngioma is characterised by BRAFv600E mutations and rarely calcifies?