Craniopharyngioma overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Marjan Khan M.B.B.S.[2]
Overview
Craniopharyngioma is a rare, benign tumor of the central nervous system (CNS). It is a partly cystic embryonic malformation that can occur in the sellar/parasellar region and can result in a wide array of symptomatology such as headaches, nausea and vomiting, visual disturbances, and endocrine disturbances.It has an incidence of 0.5 to 2 cases per million persons per year. Half of these cases occur during the first two decades of life. It represents 1.2% to 4% of all childhood intracranial tumors. It has a classical bimodal distribution of incidence with increased incidence rates in patients aged five to 14 years and 50 to 74 years. Craniopharyngioma has a very high recurrence rate, with reported rates as high as 50%. There are two subtypes of craniopharyngioma: adamantinomatous and papillary. It most commonly presents with signs of increased intracranial pressure (ICP) including a headache and nausea and vomiting along with visual and endocrine disturbances. In children, failure to thrive and decreased growth rate can be the initial presentation. Multiple modalities can be implemented in the management of craniopharyngioma, including neurological surgery, radiotherapy, and instillation of sclerosing substances.
Historical perspective
Primitive concepts of the function of the pituitary gland were formulated in the 4th century BC by Hippocrates. Harvey Cushing (1869–1939), has had a major impact in the understanding of pituitary function and surgery but he was not the first surgeon to attempt pituitary surgery; this honor goes in 1889 to Sir Victor Horsley. Hermann Schloffer (1868–1937), an Austrian surgeon, guided by the works of Davide Giordano, performed the first transfacial transsphenoidal approach in 1907. In the 1960s, transsphenoidal surgery underwent a revival and has been universally accepted thanks to great figures such as Guiot and Hardy.
Classification
- Craniopharyngiomas occur in two histological subtypes; an adamantinomatous form and Papillary.
- Adamantinomatous form that is the most common pediatric variant and a Papillary form that is found almost exclusively in adults.
- The pediatric form is thought to arise from epithelial remnants of the craniophayngeal duct or Rathke's pouch, an embryologic structure that develops into the anterior pituitary.
- Both forma typically have solid and cystic components and are often calcified on imaging.
- Recent genetic analysis has also shown differences between these two subtypes.
- Mutations in B-catenin (CTNNB1), a downstream effector of the Wnt pathway that is, involved in cellular growth and development, has been described in 60–96% of adamantinomatous craniopharyngiomas.
- Papillary craniopharyngiomas recently have been discovered to frequently harbor V600E mutations of the BRAF gene, which is a key player in the mitogen-activated protein kinase pathway.
Pathophysiology
Differentiating craniopharyngioma from other diseases
Epidemiology and demographics
- The overall incidence of craniopharyngioma is approximately 0.5 to 2 per 100,000 per year.
- The Central Brain Tumor Registry of the United States revealed an average of 338 cases diagnosed annually, with 96 occurring in children aged 0 to 4 years in this country.
- They are the most common nonglial tumor in the pediatric population, representing 6–9% of all brain tumors in this age range.
- No variance by gender or race was found.
- some studies report that it appear to be more common, with higher incidence rates in Japan and some parts of Africa.
- The age distribution is bimodal with a peak in childhood and a second peak among middle-aged and older adults.
- No statistically significant differences have been described regarding demographic characteristics such as age, gender, race, and geographical location
- No definite genetic relationship has been found and few familial cases reported.
- Craniopharyngioma has a very high recurrence rate, with reported rates as high as 50%.
- Interesting cases of craniopharyngioma have been reported, including craniopharyngiomas of the cerebellopontine angle, malignant transformation of craniopharyngiomas and familial cases of craniopharyngiomas.
- At the time of diagnosis, 20–50% of children are noted to have hormonal insufficiencies, making endocrine testing mandatory.