Craniopharyngioma

OVERVIEW:

Craniopharyngiomas are benign brain tumors that arise near the pituitary gland and pituitary stalk and are typically both cystic and solid in structure. They occur most commonly in childhood and adolescence and in later adult life, after age 50. They account for 10-15% of sellar and suprasellar tumors (tumors that occur in and above the pituitary gland) and 50-60% of sellar and suprasellar tumors in children. They are usually not discovered until they impinge upon important structures around them, and are frequently quite large (over 3 cm) when detected. Although they are benign (not malignant) tumors, these tumors tend to become adherent to structures around the pituitary gland and stalk, including the optic nerves, optic chiasm, intracranial arteries and the brain itself. They are thought to arise from remnants of the craniopharyngeal duct or Rathke's pouch which are developmental structures related to the primitive gut. They are thought to be closely related to Rathke’s Cleft Cysts (RCCs).

SYMPTOMS:

Craniopharyngiomas can cause a variety of symptoms depending upon their location. If the tumor compresses the pituitary stalk or gland, the tumor can cause partial or complete pituitary hormone deficiency which may lead to growth failure, delayed puberty, loss of normal menstrual function or sexual desire, increased sensitivity to cold, fatigue, constipation, dry skin, nausea, low blood pressure, and depression. Pituitary stalk compression can also cause diabetes insipidus (DI), and increase prolactin levels causing a milky discharge from the breast (galactohhrea). If the tumor compresses the optic chiasm or nerves, then visual loss can result. Involvement of the hypothalamus, an area at the base of the brain, may result in obesity, increased drowsiness and temperature regulation abnormalities. Other symptoms especially with larger tumors may include personality changes, headache, confusion, and vomiting.

DIAGNOSIS:

A craniopharyngioma is typically diagnosed with an MRI of the pituitary region. Many craniopharyngiomas will also be well seen on a CT scan especially since some are partially calcified (containing calcium deposits). A complete pituitary hormonal blood evaluation should also be performed. Other possible diagnoses to consider with a cystic pituitary mass is a cystic pituitary adenoma or an arachnoid cyst.

TREATMENT:

Surgery: The best initial treatment for a craniopharyngioma is surgical removal by either the endonasal transsphenoidal approach or by a supra-orbital “eyebrow” craniotomy. The goal of surgery is to completely remove the tumor while improving vision and brain function. Because of their tendency to be adherent to the optic chiasm, other nerves and important blood vessels, complete tumor removal may not be possible in up to 50% of patients.

Radiosurgery (SRS) or Stereotactic Radiotherapy (SRT): With incomplete removal, stereotactic radiotherapy (SRT) or stereotactic radiosurgery (SRS), are typically used to prevent further tumor growth. Additionally, because of the tendency for craniopharyngiomas to recur, repeat MRIs or CT scans should be obtained at least every six months for the first 5 years after surgery or radiation therapy and then at least annually thereafter.
Hormonal Replacement Therapy: Many patients with a craniopharyngioma will develop pituitary hormonal deficits because of the tumor itself, surgery or as a consequence of radiotherapy. Such patients will require hormone replacement therapy such thyroid, cortisol, testosterone (men), estrogen (women) and/or DDAVP for diabetes insipidus. Because hormonal deficiencies can develop many years after radiation treatment, patients treated with radiation should have periodic hormonal evaluations throughout their lifetimes. Regular follow-up with an endocrinologist is recommended for all patients with a craniopharyngioma.