====== Intracranial germ cell tumor ======

[[Intracranial]] [[germ cell tumor]]s (iGCTs) are a heterogeneous group of tumors with peculiar characteristics clearly distinguished from other [[brain tumor]]s of [[neuroepithelial]] origin
((Cormenzana Carpio M, Nehme Álvarez D, Hernández Marqúes C, Pérez Martínez A,
Lassaletta Atienza A, Madero López L. [Intracranial germ cell tumours: A 21-year 
review]. An Pediatr (Barc). 2017 Jan;86(1):20-27. doi:
10.1016/j.anpedi.2016.03.005. Epub 2016 Apr 8. Spanish. PubMed PMID: 27068071.
)). 

Primary intracranial [[germinoma]]s are a rare subset of [[intracranial tumor]]s derived from mis-incorporated [[germ cell]]s within the folding [[neural plate]] during embryogenesis. 

When they arise in the CNS, GCTs occur in the midline in the suprasellar and/or [[pineal region]] (simultaneous suprasellar and pineal region lesions is diagnostic of a GCT, so-called synchronous germ cell tumors, comprise 13% of GCTs, and are highly sensitive to XRT
((Sugiyama K, Uozumi T, Kiya K, Mukada K, Arita K, Kurisu K, Hotta T, Ogasawara H, Sumida M. Intracra- nial germ-cell tumor with synchronous lesions in the pineal and suprasellar regions: report of six cases and review of the literature. Surg Neurol. 1992; 38:114–120)).

In the pineal region, these tumors occur predominantly in males. In females, GCTs are more common in the suprasellar region
((Hoffman HJ, Ostubo H, Hendrick EB, et al. Intracra- nial Germ-Cell Tumors in Children. J Neurosurg. 1991; 74:545–551)).

Aside from benign teratomas, all intracranial GCTs are malignant and may metastasize via CSF and sys- temically. 

===== Classification =====

[[Intracranial germ cell tumor classification]]


===== Epidemiology =====

see [[Intracranial germ cell tumor epidemiology]].

====Pathogenesis====
IGs may result from the mismigration of embryonic cells into the neural plate area and so the midline of the embryonic disk has been reported to be a site of germ cell tumor origin
((Sano K. Pathogenesis of intracranial germ cell tumors reconsidered. J
Neurosurg. 1999 Feb;90(2):258-64. Review. PubMed PMID: 9950496.
)).

====Clinical features====
Intracranial germinoma is almost always located in the midline and its more common manifestation is hydrocephalus due to aqueductal occlusion. 

===== Diagnosis =====

[[Intracranial germ cell tumor diagnosis]].

====Differential diagnosis====
Differential diagnoses of cognitive symptoms are various, but germinoma could be considered as a possible pathology for it. Early MRI and tumor marker exams are recommended, unless organic brain diseases are completely denied. MR spectroscopy and biopsy with ventriculoscope are useful for diagnosis
((Wataya T, Ishizaki R, Kitagawa M, Tashiro Y. Germinoma in the bilateral basal 
ganglia presented with cognitive deterioration. Childs Nerv Syst. 2015 Jan 11.
[Epub ahead of print] PubMed PMID: 25577220.)).

The pathophysiology of IGs masquerading as inflammatory brain disease (IBD),  remains unclear, but one hypothesis is that the leptomeningeal dissemination of germinoma cells precedes tumor development, and that non-specific inflammatory reactions in tumor tissues may generate intrathecal IgG 
((Birnbaum T, Pellkofer H, Buettner U. Intracranial germinoma clinically
mimicking chronic progressive multiple sclerosis. J Neurol. 2008
May;255(5):775-6. doi: 10.1007/s00415-008-0811-0. Epub 2008 Feb 29. PubMed PMID: 
18299951.
)).

To better distinguish such atypical IGs from IBD, Tao et al. reported the role of MRI and tumor markers in the CSF, and found that an increased level of Beta-human chorionic gonadotropin in the CSF preceded MRI abnormalities
((Tao Y, Lian D, Hui-juan Z, Hui P, Zi-meng J. Value of brain magnetic resonance
imaging and tumor markers in the diagnosis and treatment of intracranial
germinoma in children. Zhongguo Yi Xue Ke Xue Yuan Xue Bao. 2011 Apr;33(2):111-5.
doi: 10.3881/j.issn.1000-503X.2011.02.002. PubMed PMID: 21529434.
)).

===== Treatment =====

[[Intracranial germ cell tumor treatment]].

===== Outcome =====

[[Intracranial germ cell tumor outcome]].

===== Case series =====

[[Intracranial germ cell tumor case series]].

===== Case reports =====

see [[Intracranial germ cell tumor case reports]].