Craniopharyngioma (CP)
A craniopharyngioma (CP) is an embryonic malformation of the sellar region and parasellar region.
Its relation to Rathke’s cleft cyst (RCC) is controversial, and both lesions have been hypothesized to lie on a continuum of ectodermal cystic lesions of the sellar region.
Jakob Erdheim (1874-1937) was a Viennese pathologist who identified and defined a category of pituitary tumors known as craniopharyngiomas. He named these lesions “hypophyseal duct tumors” (Hypophysenganggeschwülste), a term denoting their presumed origin from cell remnants of the hypophyseal duct, the embryological structure through which Rathke’s pouch migrates to form part of the pituitary gland. He described the two histological varieties of these lesions as the adamantinomatous and the squamous-papillary types. He also classified the different topographies of craniopharyngiomas along the hypothalamus-pituitary axis. Finally, he provided the first substantial evidence for the functional role of the hypothalamus in the regulation of metabolism and sexual functions. Erdheim’s monograph on hypophyseal duct tumors elicited interest in the clinical effects and diagnosis of pituitary tumors. It certainly contributed to the development of pituitary surgery and neuroendocrinology. Erdheim’s work was greatly influenced by the philosophy and methods of research introduced to the Medical School of Vienna by the prominent pathologist Carl Rokitansky. Routine practice of autopsies in all patients dying at the Vienna Municipal Hospital (Allgemeines Krankenhaus), as well as the preservation of rare pathological specimens in a huge collection stored at the Pathological-Anatomical Museum, represented decisive policies for Erdheim’s definition of a new category of epithelial hypophyseal growths. Because of the generalized use of the term craniopharyngioma, which replaced Erdheim’s original denomination, his seminal work on hypophyseal duct tumors is only referenced in passing in most articles and monographs on this tumor.
Jakob Erdheim should be recognized as the true father of craniopharyngiomas 1).
Epidemiology
Origin
Its relation to Rathke’s cleft cyst (RCC) is controversial, and both lesions have been hypothesized to lie on a continuum of cystic ectodermal lesions of the sellar region.
It grows close to the optic nerve, hypothalamus and pituitary gland.
Craniopharyngiomas frequently grow from remnants of the Rathke pouch, which is located on the cisternal surface of the hypothalamic region. These lesions can also extend elsewhere in the infundibulohypophyseal axis.
These tumors can also grow from the infundibulum or tuber cinereum on the floor of the third ventricle, developing exclusively into the third ventricle.
Classification
Molecular and genetic markers
Genetic and immunological markers show variable expression in different types of Craniopharyngioma. BRAF is implicated in tumorigenesis in papillary Craniopharyngioma (pCP), whereas CTNNB1 and EGFR are often overexpressed in adamantinomatous Craniopharyngioma (aCP) and VEGF is overexpressed in aCP and Craniopharyngioma recurrence. Targeted treatment modalities inhibiting thesepathways can shrink or halt progression of CP. In addition, Epidermal growth factor receptor tyrosine kinase inhibitors may sensitize tumors to radiation therapy. These – drugs show promise in medical management and neoadjuvant therapy for CP. Immunotherapy, including anti-interleukin 6 (IL-6) drugs and interferon treatment, are also effective in managing tumor growth. Ongoing – clinical trials in CP are limited but are testing BRAF/MET inhibitors and IL-6 monoclonal antibodies.
Genetic and immunological markers show variable expression in different subtypes of CP. Several current molecular treatments have shown some success in the management of this disease. Additional clinical trials and targeted therapies will be important to improve CP patient outcomes 2).
Craniopharyngioma Natural History
Clinical Features
Diagnosis
Differential diagnosis
ependymoma, pilocytic astrocytoma, choroid plexus papilloma (CPP), craniopharyngioma, primitive neuroectodermal tumor (PNET), choroid plexus carcinoma (CPC), immature teratoma, atypical teratoid rhabdoid tumor (AT/RT), anaplastic astrocytoma, and gangliocytoma.
Compared with craniopharyngiomas, sellar gliomas presented with a significantly lower ratio of visual disturbances, growth hormone deficiencies, lesion cystic changes, and calcification. Sellar gliomas had significantly greater effects on the patients’ mentality and anatomical brain stem involvement 3).
Co-occurrence
Simultaneous sellar-suprasellar craniopharyngioma and intramural clival chordoma, successfully treated by a single staged, extended, fully endoscopic endonasal approach, which required no following adjuvant therapy is reported 4).
