What is a craniopharyngioma?

What is Craniopharyngioma?

Craniopharyngioma is a rare, benign epithelial tumor of the sellar and suprasellar region that arises from embryonic remnants of Rathke's pouch, accounting for 1-3% of all intracranial neoplasms. 1, 2

Pathologic Classification

Two distinct histologic subtypes exist with different clinical characteristics 3:

• Adamantinomatous craniopharyngioma: Predominantly affects children, characterized by cystic spaces containing "motor oil"-like fluid, palisading peripheral epithelial cells, keratinization, and calcification 3
• Papillary craniopharyngioma: Occurs exclusively in adults, typically lacks the cystic changes and calcifications seen in the adamantinomatous type 3

Recent molecular insights reveal that papillary craniopharyngiomas harbor BRAF-V600E mutations, opening potential avenues for targeted therapy 4

Anatomic Location and Growth Pattern

Craniopharyngiomas characteristically arise in the sellar/suprasellar region with specific anatomic relationships 1, 5:

• Suprasellar extension is the most common growth pattern, with tumors expanding upward from the sella to compress the optic chiasm and hypothalamus 5
• Larger tumors cause sellar remodeling including enlargement, bony erosion, suprasellar extension, invasion into the clivus, or sphenoid sinus involvement 5
• The tumor can cause bone-destructive lesions of the skull base affecting the sella turcica 5
• Displacement or encasement of suprasellar vessels may occur, requiring MRA for surgical planning 5

Clinical Manifestations

The clinical presentation reflects the tumor's anatomic location and mass effect 6, 4:

Endocrine Dysfunction

• Hypopituitarism develops from mass effect on the pituitary gland, often requiring lifelong hormone replacement 5
• Growth hormone deficiency is particularly common in pediatric patients 4

Visual Impairment

• Bitemporal hemianopsia or other visual field defects result from optic chiasm compression 1
• Visual recovery is unlikely after the first postoperative month, making early surgical intervention critical 1, 5

Hypothalamic Involvement

• Hypothalamic obesity and severe metabolic dysfunction can occur with posterior hypothalamic involvement 4
• Psychopathological symptoms and quality of life impairment are frequent sequelae 4

Increased Intracranial Pressure

• Obstructive hydrocephalus may develop with larger tumors 4

Diagnostic Imaging

MRI using high-resolution pituitary protocols is the gold standard for diagnosis 1, 5:

• Pre-contrast T1 and T2 sequences plus post-contrast T1-weighted imaging with thin slices (2mm) are essential 1
• Volumetric gradient echo sequences after contrast enhance sensitivity for tumor detection 1
• 3-Tesla MRI improves anatomical delineation for surgical planning 1

CT imaging provides complementary information 1:

• Calcification detection is superior with CT and helps distinguish craniopharyngioma from hemorrhagic pituitary adenoma 1
• Approximately 90% of pediatric adamantinomatous craniopharyngiomas show calcification on CT 3
• Osseous changes and skull base involvement are better characterized with CT 1

Differential Diagnosis

Key considerations for sellar/suprasellar masses include 1:

• Pituitary adenoma (most common sellar mass)
• Rathke's cleft cyst
• Germ cell tumors (especially in children)
• Pilocytic/pilomyxoid astrocytoma
• Meningioma
• Dermoid/epidermoid cysts

The characteristic location, calcification pattern, and bony changes help distinguish craniopharyngiomas from other sellar masses 5

Treatment Approach

Transsphenoidal resection is the mainstay of treatment for most craniopharyngiomas 5, 4:

• Complete resection is the goal when tumor is favorably localized without hypothalamic involvement 4
• Limited hypothalamus-sparing surgery followed by local irradiation is recommended for tumors with unfavorable localization 4
• Endoscopic endonasal approaches are increasingly utilized, offering caudocranial midline access without manipulation of neurovascular structures 3

Radiation therapy is effective for controlling postoperative tumor remnants and reducing recurrence rates 2, 4, 7:

• Proton beam therapy may reduce long-term side effects 4
• Radiotherapy carries significant risks including hypopituitarism in up to 80% of patients by 10-15 years post-treatment 8

Clinical Course and Prognosis

Despite being histologically benign, craniopharyngiomas present significant management challenges 6, 4:

• Recurrence and progression are frequent, even after apparent complete resection 4
• Hypothalamic involvement or surgical injury to posterior hypothalamic areas results in serious sequelae compromising quality of life 4
• The tumor should be managed as a chronic disease requiring lifelong multidisciplinary care 4

Surveillance Recommendations

Close monitoring for tumor recurrence is essential 8:

• MRI surveillance at 3 and 6 months, then at 1,2,3, and 5 years after surgery 8
• Ongoing endocrine assessment and hormone replacement as hormonal deficiencies are typically permanent 5
• Visual field monitoring, particularly in the first postoperative month when recovery is still possible 1