CRANIOPHARYNGIOMA
Craniopharyngioma is the most common tumor found in the region of the pituitary gland in children and adolescents and constitutes about 3% of all intracranial tumors and up to 10% of all childhood brain tumors. Craniopharyngiomas—histologically benign epithelioid tumors arising from embryonic squamous remnants of Rathke pouch—may be large (e.g., 6 cm in diameter) and invade the third ventricle and associated brain structures. This tumorous process is usually located above the sella turcica, depressing the optic chiasm and extending up into the third ventricle. Less frequently, craniopharyngiomas are located within the sella, causing compression of the pituitary gland and frequently eroding the boney confines of the sella turcica. Signs and symptoms—primarily caused by mass effect—typically occur in the adolescent years and rarely after age 40 years. The mass effect symptoms include vision loss by compression of the optic chiasm; diabetes insipidus by invasion or disruption of the hypothalamus or pituitary stalk; hypothalamic dysfunction (e.g., obesity with hyperphagia, hypersomnolence, disturbance in temperature regulation); various degrees of anterior pituitary insufficiency (e.g., growth hormone deficiency with short stature in childhood, hypogonadism, adrenal insufficiency, hypothyroidism); hyperprolactinemia caused by compression of the pituitary stalk or damage to the dopaminergic neurons in the hypothalamus; signs and symptoms of increased intracranial pressure (e.g., headache, projectile emesis, papilledema, optic atrophy); symptoms of hydrocephalus (e.g., mental dullness and confusion) when large tumors obstruct the flow of cerebrospinal fluid; and cranial nerve palsies caused by cavernous sinus invasion.
The findings on radiologic imaging
are quite characteristic. Plain skull radiographs and computed tomography (CT)
show irregular calcification in the suprasellar region. Magnetic resonance
imaging (MRI) typically shows a multilobulated cystic structure that is usually
suprasellar in location, but it may also appear to arise from the sella. The cystic regions are usually
filled with a turbid, cholesterol-rich, viscous fluid. The walls of the cystic
and solid components are composed of whorls and cords of epithelial cells
separated by a loose network of stellate cells. If there are intercellular
epithelial bridges and keratohyalin, the tumor is classified as an adamantinoma.
Treatment options for patients with
craniopharyngiomas include observation, endonasal transsphenoidal surgery for smaller intrasellar tumors,
craniotomy for larger suprasellar tumors, stereotactic radiotherapy, or a
combination of these modalities. Most of these treatment approaches result in
varying degrees of anterior or posterior pituitary hormone deficits (or both).
In addition, recurrent disease after treatment is common (40%) because of
tumor adherence to surrounding structures, and long-term follow-up is
indicated.
