What are Craniopharyngiomas?
Craniopharyngiomas are slow growing tumors that arise near the pituitary gland and stalk. They are derived from pituitary gland embryonic tissues. Usually the structure of craniopharyngioma tumors is a solid cyst. They are extra-axial, meaning they are within the skull, or intracranial, but outside the brain itself, and calcified cystic tumors.
These tumors develop from the tooth-forming tissues present in the supracellar region. Therefore, they contain deposits of calcium, which are visible on x-rays.
Craniopharyngiomas mostly occur in children, but they can also develop in adults over 50 years of age. These tumors are usually discovered when they start to interrupt surrounding structures. They are usually more than 3 cm in size by the time they are detected.
Although these tumors are not malignant, they sometimes invade the surrounding organs and structures. For example, they may become adherent to the pituitary gland, optic nerves, intracranial arteries and to the brain.
Causes of Craniopharyngiomas
The causes of craniopharyngiomas are not yet fully known or understood. Doctors believe that it is primarily a congenital disorder. Embryonic cells are found in a part of the pituitary gland called Rathke's pouch. In the patients affected by craniopharyngiomas, the embryonic cells in the Rathke's pouch become cancerous. Over time, they can multiply to form a tumor.
Symptoms of Craniopharyngiomas
The symptoms of craniopharyngiomas can exhibit in three forms:
- Increases in the pressure on the brain: Increased intracranial pressure can cause symptoms such as headache, nausea, vomiting, and difficulties in balance and coordination.
- Changes in the function of the pituitary gland: If a craniopharyngioma starts to put pressure on the pituitary gland, it may disrupt its function and cause pituitary hormone deficiency. This can lead to symptoms such as delayed puberty, stunted growth, loss of sexual desire, sensitivity to cold, excessive thirst, constipation, excessive urination, dry skin, nausea, and depression.
- Damages to the optic nerves: If the tumor causes damage to the optic nerves, vision problems might develop. These disorders are usually permanent and may worsen after surgery to treat the tumor.
Other symptoms may include behavioral and learning problems. Obesity, increased sleepiness and temperature regulation abnormalities may occur if the tumor affects the area at the base of the brain.
Diagnosis of Craniopharyngiomas
Computed tomography, or CT, scan and magnetic resonance imaging, or MRI, are used to diagnose and evaluate these tumors. These techniques reveal the size of the tumor and outline the ventricular system.
A complete evaluation of the pituitary hormonal blood may be performed to aid diagnosis of these tumors.
Evaluation of the endocrine hormones may be needed to find out if any hormonal imbalance exists, since craniopharyngiomas can disrupt the function of pituitary gland and thus the hormonal balance.
Neurological examination may help to highlight some of the symptoms of these tumors.
Surgery is the traditional treatment option for craniopharyngiomas. The goal is to remove the cells affected the tumor.
For some patients, radiation treatment is the best option. In such cases, radiation therapy is used instead of surgery or along with a smaller surgery. At times, it is not possible to completely remove the tumor surgically. In such cases, radiation therapy is usually imperative.