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Although the causes of craniopharyngioma is unknown, it can occur in both children and adults, with a peak in incidence at 9 to 14 years of age. There are approximately 120 cases diagnosed each year in the United States in patients under the age of 19 years old. In fact, more than 50% of all patients with craniopharyngioma are under the age of 18 years. There is no clear association of the tumor with a particular gender or race. It is not really known what causes craniopharyngiomas, but they do not appear to "run in families" or to be directly inherited from the parents.
Treatment generally consists of subfrontal or transsphenoidal excision. Surgery using the transsphenoidal route is often performed by a joint team of ENT and neurosurgeons. Because of the location of the craniopharyngioma near the brain and skullbase, a surgical navigation system might be used to verify the position of surgical tools during the operation.
Additional radiotherapy is also used if total removal is not possible. Due to the poor outcomes associated with damage to the pituitary and hypothalamus from surgical removal and radiation, experimental therapies using intracavitary phosphorus-32, yttrium, or bleomycin delivered via an external reservoir are sometimes employed, especially in young patients. The tumor, being in the pituitary gland, can cause secondary health problems. The immune system, thyroid levels, growth hormone levels and testosterone levels can be compromised from craniopharygioma. All of the before mentioned health problems can be treated with modern medicine. There is no high quality evidence looking at the use of bleomycin in this condition.
The most effective treatment 'package' for the malignant craniopharyngiomas described in literature is a combination 'gross total resective' surgery with adjuvant chemo radiotherapy. The chemotherapy drugs Paclitaxel and Carboplatin have shown a clinical (but not statistical) significance in increasing the survival rate in patients who've had gross total resections of their malignant tumours.
There is evidence that suppression of matrix metalloproteinase-2 may inhibit the local invasiveness of ameloblastoma, however, this was only demonstrated "in vitro". There is also some research suggesting that αβ integrin may participate in the local invasiveness of ameloblastomas.
A recent study discovered a high frequency of BRAF V600E mutations (15 of 24 samples, 63%) in solid/multicystic ameloblastoma. These data suggests drugs targeting mutant BRAF as potential novel therapies for ameloblastoma.
Treatment options depend on the type of tumor and on its size:
- Prolactinomas are most often treated with cabergoline or quinagolide (both dopamine agonists), which decrease tumor size as well as alleviates symptoms, followed by serial imaging to detect any increase in size. Treatment where the tumor is large can be with radiation therapy or surgery, and patients generally respond well. Efforts have been made to use a progesterone antagonist for the treatment of prolactinomas, but so far have not proved successful.
- Somatotrophic adenomas respond to octreotide, a long-acting somatostatin analog, in many but not all cases according to a review of the medical literature. Unlike prolactinomas, thyrotrophic adenomas characteristically respond poorly to dopamine agonist treatment.
- Surgery is a common treatment for pituitary tumors. The normal approach is Trans-sphenoidal adenectomy, which usually can remove the tumor without affecting the brain or optic nerves.
- Danazol is a steroid compound that has been labelled as an "Anterior pituitary suppressant".
While chemotherapy, radiation therapy, curettage and liquid nitrogen have been effective in some cases of ameloblastoma, surgical resection or enucleation remains the most definitive treatment for this condition. In a detailed study of 345 patients, chemotherapy and radiation therapy seemed to be contraindicated for the treatment of ameloblastomas. Thus, surgery is the most common treatment of this tumor. Because of the invasive nature of the growth, excision of normal tissue near the tumor margin is often required. Some have likened the disease to basal cell carcinoma (a skin cancer) in its tendency to spread to adjacent bony and sometimes soft tissues without metastasizing. While rarely not a cancer that actually invades adjacent tissues, ameloblastoma is suspected to spread to adjacent areas of the jaw bone via marrow space. Thus, wide surgical margins that are clear of disease are required for a good prognosis. This is very much like surgical treatment of cancer. Often, treatment requires excision of entire portions of the jaw.
Radiation is ineffective in many cases of ameloblastoma. There have also been reports of sarcoma being induced as the result of using radiation to treat ameloblastoma. Chemotherapy is also often ineffective. However, there is some controversy regarding this and some indication that some ameloblastomas might be more responsive to radiation that previously thought.
Carcinomas that metastasize into the pituitary gland are uncommon and typically seen in the elderly, with lung and breast cancers being the most prevalent, In breast cancer patients, metastases to the pituitary gland occur in approximately 6-8% of cases.
Symptomatic pituitary metastases account for only 7% of reported cases. In those who are symptomatic Diabetes insipidus often occurs with rates approximately 29-71%. Other commonly reported symptoms include anterior pituitary dysfunction, visual field defects, headache/pain, and ophthalmoplegia.
Foroozen divides the causes of chiasmal syndromes into intrinsic and extrinsic causes. Intrinsic implies thickening of the chiasm itself and extrinsic implies compression by another structure. Other less common causes of chiasmal syndrome are metabolic, toxic, traumatic or infectious in nature.
Intrinsic etiologies include gliomas and multiple sclerosis. Gliomas of the optic chiasm are usually derived from astrocytes. These tumors are slow growing and more often found children. However, they have a worse prognosis, especially if they have extended into the hypothalamus. They are frequently associated with neurofibromatosis type 1 (NF-1). Their treatment involves the resection of the optic nerve. The supposed artifactual nature of Wilbrand's knee has implications for the degree of resection that can be obtained, namely by cutting the optic nerve immediately at the junction with the chiasm without fear of potentially resulting visual field deficits.
The vast majority of chiasmal syndromes are compressive. Ruben et al. describe several compressive etiologies, which are important to understand if they are to be successfully managed. The usual suspects are pituitary adenomas, craniopharyngiomas, and meningiomas.
Pituitary tumors are the most common cause of chiasmal syndromes. Visual field defects may be one of the first signs of non-functional pituitary tumor. These are much less frequent than functional adenomas. Systemic hormonal aberrations such as Cushing’s syndrome, galactorrhea and acromegaly usually predate the compressive signs. Pituitary tumors often encroach upon the middle chiasm from below. Pituitary apoplexy is one of the few acute chiasmal syndromes. It can lead to sudden visual loss as the hemorrhagic adenoma rapidly enlarges.
The embryonic remnants of Rathke’s pouch may undergo neoplastic change called a craniopharyngioma. These tumors may develop at any time but two age groups are most at risk. One peak occurs during the first twenty years of life and the other occurs between fifty and seventy years of age. Craniopharyngiomas generally approach the optic chiasm from behind and above. Extension of craniopharyngiomas into the third ventricle may cause hydrocephalus.
Meningiomas can develop from the arachnoid layer. Tuberculum sellae and sphenoid planum meningiomas usually compress the optic chiasm from below. If the meningioma arises from the diaphragma sellae the posterior chiasm is damaged. Medial sphenoid ridge types can push on the chiasm from the side. Olfactory groove subfrontal types can reach the chiasm from above. Meningiomas are also associated with neurofibromatosis type 1. Women are more prone to develop meningiomas.
Children with cancer are at risk for developing various cognitive or learning problems. These difficulties may be related to brain injury stemming from the cancer itself, such as a brain tumor or central nervous system metastasis or from side effects of cancer treatments such as chemotherapy and radiation therapy. Studies have shown that chemo and radiation therapies may damage brain white matter and disrupt brain activity.
Familial and genetic factors are identified in 5-15% of childhood cancer cases. In <5-10% of cases, there are known environmental exposures and exogenous factors, such as prenatal exposure to tobacco, X-rays, or certain medications. For the remaining 75-90% of cases, however, the individual causes remain unknown. In most cases, as in carcinogenesis in general, the cancers are assumed to involve multiple risk factors and variables.
Aspects that make the risk factors of childhood cancer different from those seen in adult cancers include:
- Different, and sometimes unique, exposures to environmental hazards. Children must often rely on adults to protect them from toxic environmental agents.
- Immature physiological systems to clear or metabolize environmental substances
- The growth and development of children in phases known as "developmental windows" result in certain "critical windows of vulnerability".
Also, a longer life expectancy in children avails for a longer time to manifest cancer processes with long latency periods, increasing the risk of developing some cancer types later in life.
There are preventable causes of childhood malignancy, such as delivery overuse and misuse of ionizing radiation through computed tomography scans when the test is not indicated or when adult protocols are used.
Chiasmal syndrome is the set of signs and symptoms that are associated with lesions of the optic chiasm, manifesting as various impairments of the sufferer's visual field according to the location of the lesion along the optic nerve. Pituitary adenomas are the most common cause; however, chiasmal syndrome may be caused by cancer, or associated with other medical conditions such as multiple sclerosis and neurofibromatosis.
Treatment of THS includes immunosuppressives such as corticosteroids (often prednisolone) or steroid-sparing agents (such as methotrexate or azathioprine).
Radiotherapy has also been proposed.
The prognosis of THS is usually considered good. Patients usually respond to corticosteroids, and spontaneous remission can occur, although movement of ocular muscles may remain damaged. Roughly 30–40% of patients who are treated for THS experience a relapse.
Several studies have shown that hypopituitarism is associated with an increased risk of cardiovascular disease and some also an increased risk of death of about 50% to 150% the normal population. It has been difficult to establish which hormone deficiency is responsible for this risk, as almost all patients studied had growth hormone deficiency. The studies also do not answer the question as to whether the hypopituitarism itself causes the increased mortality, or whether some of the risk is to be attributed to the treatments, some of which (such as sex hormone supplementation) have a recognized adverse effect on cardiovascular risk.
The largest study to date followed over a thousand people for eight years; it showed an 87% increased risk of death compared to the normal population. Predictors of higher risk were: female sex, absence of treatment for sex hormone deficiency, younger age at the time of diagnosis, and a diagnosis of craniopharyngioma. Apart from cardiovascular disease, this study also showed an increased risk of death from lung disease.
Quality of life may be significantly reduced, even in those people on optimum medical therapy. Many report both physical and psychological problems. It is likely that the commonly used replacement therapies do not completely mimic the natural hormone levels in the body. Health costs remain about double those of the normal population.
Hypopituitarism is usually permanent. It requires lifelong treatment with one or more medicines.
Pituitary tumors require treatment when they are causing specific symptoms, such as headaches, visual field defects or excessive hormone secretion. Transsphenoidal surgery (removal of the tumor by an operation through the nose and the sphenoidal sinuses) may, apart from addressing symptoms related to the tumor, also improve pituitary function, although the gland is sometimes damaged further as a result of the surgery. When the tumor is removed by craniotomy (opening the skull), recovery is less likely–but sometimes this is the only suitable way to approach the tumor. After surgery, it may take some time for hormone levels to change significantly. Retesting the pituitary hormone levels is therefore performed 2 to 3 months later.
Prolactinomas may respond to dopamine agonist treatment–medication that mimics the action of dopamine on the lactrotrope cells, usually bromocriptine or cabergoline. This approach may improve pituitary hormone secretion in more than half the cases, and make supplementary treatment unnecessary.
Other specific underlying causes are treated as normally. For example, hemochromatosis is treated by venesection, the regular removal of a fixed amount of blood. Eventually, this decreases the iron levels in the body and improves the function of the organs in which iron has accumulated.
When treated with GH, a severely deficient child will begin to grow faster within months. In the first year of treatment, the rate of growth may increase from half as fast as other children are growing to twice as fast (e.g., from 1 inch a year to 4 inches, or 2.5 cm to 10). Growth typically slows in subsequent years, but usually remains above normal so that over several years a child who had fallen far behind in his height may grow into the normal height range. Excess adipose tissue may be reduced.
GH supplementation is not recommended medically for the physiologic age-related decline in GH/IGF secretion. It may be appropriate in diagnosed adult-onset deficiency, where a weekly dose approximately 25% of that given to children is given. Lower doses again are called for in the elderly to reduce the incidence of side effects and maintain age-dependent normal levels of IGF-1.
In many countries, including the UK, the majority view among endocrinologists is that the failure of treatment to provide any demonstrable, measurable benefits in terms of outcomes means treatment is not recommended for all adults with severe GHD, and national guidelines in the UK as set out by NICE suggest three criteria which all need to be met for treatment to be indicated:
1. Severe GH deficiency, defined as a peak GH response of <9mU/litre during an insulin tolerance test
2. Perceived impairment of quality of life, as assessed by questionnaire
3. They are already treated for other pituitary hormone disorders
Where treatment is indicated, duration is dependent upon indication.
Cost of adult treatment in the UK is 3000-4000 GBP annually.
All causes in this category are genetic, and generally very rare. These include mutations to the "SF1" transcription factor, congenital adrenal hypoplasia due to "DAX-1" gene mutations and mutations to the ACTH receptor gene (or related genes, such as in the Triple A or Allgrove syndrome). "DAX-1" mutations may cluster in a syndrome with glycerol kinase deficiency with a number of other symptoms when "DAX-1" is deleted together with a number of other genes.
Autoimmune adrenalitis is the most common cause of Addison's disease in the industrialised world. Autoimmune destruction of the adrenal cortex is caused by an immune reaction against the enzyme 21-hydroxylase (a phenomenon first described in 1992). This may be isolated or in the context of autoimmune polyendocrine syndrome (APS type 1 or 2), in which other hormone-producing organs, such as the thyroid and pancreas, may also be affected.
Adrenal destruction is also a feature of adrenoleukodystrophy (ALD), and when the adrenal glands are involved in metastasis (seeding of cancer cells from elsewhere in the body, especially lung), hemorrhage (e.g. in Waterhouse-Friderichsen syndrome or antiphospholipid syndrome), particular infections (tuberculosis, histoplasmosis, coccidioidomycosis), or the deposition of abnormal protein in amyloidosis.