Craniopharyngioma (Erdheim tumor) is a rare, benign neoplasm, that develops from epithelium derived from Rathke's pouch and usually affects children.
This tumor-type is one that exhibits slow growth. The symptoms often show insidiously and they do not become obvious until the tumor has attained a diameter of about 3cm . The interval between the first symptoms and actual diagnosis often ranges between 1-2 years.
The most common symptoms are as follows:
The headache is dull, continuous and positional. It is equally progressive and becomes severe when the endocrine symptoms have become obvious .
Again, 40% of patients exhibit constipation, cold intolerance, fatigue and weight gain. All of these are signs of hypothyroidism.
25% of patients have equally shown vomiting, nausea, anorexia, confusion, lethargy, cardiac arrhythmias, hyperkalemia, hypoglycaemia and orthostatic hypotension. All of these are signs of adrenal failure.
20% of patients have also shown presence of diabetes insipidus characterised by excessive fluid intake and urination. In younger patients, delayed puberty and growth failure are other symptoms.
80% of adults complain of decrease in sexual drive while 90% of men show impotence. Most women equally complain about amenorrhea.
To evaluate craniopharyngioma diagnostically, precontrast and postcontrast CT (computed topography), MRA (magnetic resonance angiography), MRI (magnetic resonance imaging), neuro-ophthalmologic evaluation, neuropsychological assessment and complete endocrinology are used .
The MIB-1 labelling index
This index measures the proliferative activity of the condition. It is often determined by making use of an immunohistochemical method with monoclonal antibody MIB-1. This index comes in handy while planning adjuvant therapy. According to a study, a condition that shows an MIB-1 labelling index of higher than 7% shows has a high chance of regrowth/recurrence.
Treatment or non-treatment of this condition by a practitioner is dependent on the exact location, size, shape and the rate of growth. The need for removal becomes very urgent if the symptoms exhibited by the patient include visual loss.
Surgery is the primary method of treatment and this requires an open cranial procedure. Today, transnasal approaches that are minimally invasive have evolved and so the condition can be treated through the nose. Hormone replacement is used to treat any side effects of treatments and of the tumor itself.
Statistics show that the survival rates for craniopharyngioma is 86% at 2 years after detection and 80% at 5 years after diagnosis .
The rate of survival varies across age groups but the best rates have been reported for younger patients aged 20 and below. Older individuals aged 65% and above have a survival rate of 38%.
A craniopharyngioma is a cystic tumor that is slow-growing, extra-axial, epithelial-squamous and calcified. It arises from the remains of the craniopharyngeal duct or the Rathke cleft (or both) and often occupies the suprasellar region .
The origin of craniopharyngioma is explained by two major hypotheses . Both hypotheses explain the craniopharyngioma spectrum and both hypotheses are complementary.
The embryogenetic theory
This theory concerns how the adenohypophis develops and how the remnant ectoblastic cells of the craniopharyngeal ductis transformed. It also concerns the involuted Rathke pouch. The Rathke pouch and the infundibulum are developed during the fourth week of gestation and they both make up the hypophysis. By the second month, they elongate and come in contact.
The metaplastic theory
This theory is related to the residual squamous epithelium which undergoes metaplasia. The residual squamous epithelium is derived from the stomodeum and usually, part of the adenohypophysis.
The dual theory
This theory shows the spectrum of the craniopharyngioma. It attributes the adamantinomatous type of tumor which is mostly seen in children to embryonic remains while the squamous papillary or adult type is attributed to metaplastic foci. The metaplastic foci is arises from mature cells of the anterior hypophysis.
In the United States, a study showed that the incidence for this condition is 0.18 per 100,000 individuals. No gender based variation has been found as well. The peak incidence is seen in adults aged 65-74 and children aged 5-14 .
Internationally, 1.4 cases per million are reported for children yearly. Generally, craniopharyngioma accounts for 1-3% of tumors in the cranium and it equally accounts for 13% of suprasellar tumors. In children, the condition represents 5-10% of all tumors and 56% of suprasellar and sellar tumors. Till date, there is no proof of definite genetic relationship there is very few records of familial cases.
Generally craniopharyngiomas have a bimodal age distribution pattern. There is a peak between the ages 5 and 14 and in older adults aged 65 and above. However, the condition can be seen across individuals across all age groups.
The condition arises from disordered embryogenesis partly as is the case with most sellar region tumors and Rathke’s cleft cysts.
However, the pathology of craniopharyngiomas and the Rathke’s cleft cysts differ . This is what shows the varying ability of the squamous cells to either go through neoplastic change to form a craniopharyngioma or to remain as a normal cyst.
The pathology is complicated even further with the observation that particular craniopharyngiomas especially those seen in childhood often look like adamantinomas and odontogenic cysts.
There are no guidelines for prevention of craniopharyngioma.
Craniopharyngioma is a brain tumor type which arises from the embryonic tissues of the pituitary gland. The condition is predominantly seen in children but also, it is seen with older adults aged 50-60 . The specific cells from which the tumor originates are part and parcel of the tooth formation process so it is common to see calcium deposits on x-rays.
Craniopharyngiomas often start from the pituitary stalk and grows into the hypothalamus. The extension is done horizontally in line with the path that shows the least resistance. This growth is in various directions as shown below:
In some cases, the tumors extend towards the sylvian fissure. In very rare occasions, the tumors have been seen growing extracranially or extradurally leading to its development into a posterior fossa or nasopharyngeal craniopharyngiomas . Another rare type of craniopharyngioma is the intraventricular craniopharyngioma.
Craniopharyngioma often looks like a collection of cysts or a single large cyst. The cysts are filled with a brownish yellow proteinaceous material which is glittery owing to the high amount of cholesterol crystals flowing in it.
The choice of approach to be used in tackling the tumor and its clinical behaviour is dictated by the primary location of the tumor and the extension pattern it has taken. Craniopharyngiomas that extend into the subfrontal spaces (prechiasmatic) and those that extend into the posterior fossa (retrochiasmatic) may not be diagnosed until they have grown in size.