A craniopharyngioma is a rare type of brain tumor derived from pituitary gland embryonic tissue that occurs most commonly in children, but also affects adults. It may present at any age, even in the prenatal and neonatal periods, but peak incidence rates are childhood-onset at 5–14 years and adult-onset at 50–74 years. People may present with bitemporal inferior quadrantanopia leading to bitemporal hemianopsia, as the tumor may compress the optic chiasm. It has a point prevalence around two per 1,000,000. Craniopharyngiomas are distinct from Rathkes cleft tumours and intrasellar arachnoid cysts. Symptoms and signs
Craniopharyngiomas are almost always benign. However, as with many brain tumors, their treatment can be difficult, and significant morbidities are associated with both the tumor and treatment. Headache (obstructive hydrocephalus)
Hypersomnia
Myxedema
Postsurgical weight gain
Polydipsia
Polyuria (diabetes insipidus) 
Vision loss (bitemporal hemianopia)
VomitingOften occurs after treatment
Growth hormone (GH) insufficiency, caused by the reduction in GH production - symptoms include:
Stunted growth and delayed puberty (in children)
General fatigue, loss of muscle mass and tone (in adults)
Pituitary insufficiency
Often occurs to some degree because craniopharyngiomas develop in the area of the pituitary stalk, which can affect the function of the pituitary gland and many other hormones
Reduction in prolactin production is very uncommon and occurs with severe pituitary insufficiency. Large pituitary tumors can paradoxically elevate blood prolactin levels due to the "stalk effect". This elevation occurs as a result of the compression of the pituitary stalk, which interferes with the brains control of prolactin production.
A computed tomography (CT) scan is also a good diagnostic tool, as it detects calcification in the tumor.Two distinct types are recognized:
Adamantinomatous craniopharyngiomas, which resemble ameloblastomas (the most common type of odontogenic tumor), are characterized by activating CTNNB1 mutations. Papillary craniopharyngiomas are characterized by BRAFv600E mutations.In the adamantinomatous type, calcifications are visible on neuroimaging and are helpful in diagnosis. The papillary type rarely calcifies. A vast majority of craniopharyngiomas in children are adamantiomatous, whereas both subtypes are common in adults. Mixed-type tumors also occur.On macroscopic examination, craniopharyngiomas are cystic or partially cystic with solid areas. On light microscopy, the cysts are seen to be lined by stratified squamous epithelium. Keratin pearls may also be seen. The cysts are usually filled with a yellow, viscous fluid rich in cholesterol crystals. Of a long list of possible symptoms, the most common presentations include headaches, growth failure, and bitemporal hemianopsia. Malignant craniopharyngioma
Craniopharyngiomas are usually successfully managed with a combination of adjuvant chemotherapy and neurosurgery. Recent research describes the rare occurrence of malignant transformations of these normally benign tumors.