Germinoma overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Simrat Sarai, M.D. [2]
Overview
A germinoma is a type of germ cell tumor[1] which is not differentiated upon examination. It may be benign or malignant.
Historical Perspective
Classification
Germinoma may be classified according to World Health Organization into two groups: germinomas and nongerminomatous germ cell tumors. Based on the tumor markers secreted into the cerebrospinal fluid (CSF) and serum, as well as by the presence of histochemical markers on tumor cells, intracranial germ cell tumors may be classified into either secreting or nonsecreting tumors. Based on the prognosis of the tumor, intracranial germ cell tumors may be classified into either good, intermediate, or poor prognosis.[2][3][4]
Pathophysiology
On gross pathology, smooth and bosselated external surface, and soft, fleshy and either cream-colored, gray, pink or tan interior are characteristic findings of germinoma. On microscopic histopathological analysis, uniform cells that resemble primordial germ cells, consisting of large, round cells with vesicular nuclei and clear or finely granular cytoplasm that is eosinophilic are characteristic findings of germinoma. Genes involved in the pathogenesis of germinoma include the chromosomal imbalance comprises gains of 1p, 8p, and 12q and losses of 13q and 18q. duplication of the short arm of chromosome 12, loss of 1p and 6q and alterations in sex chromosomes in children, alterations of the p14 gene, mutations of the c-kit gene, aberrations of CCND2 (12P13), and RB1, and and gain-of-function mutations of KIT. The progression to germinoma usually involves the mutations of the KIT/RAS signalling or AKT1/mtor pathways and cyclin/CDK-RB-E2F pathway if CCND2 (12P13) and RB1 genes are aberrated.[5][6][7][8][9][10][11][12]
Causes
There are no established causes for germinoma. However, several theories have been postulated to define the cause of germ cell tumors. GCTs arise from primordial germ cells that migrate to the germinal ridges in the developing embryo. The process of migration appears to be under the control of complex molecular events. Alteration in any of these molecular pathways may give rise to GCTs. Rather than laterally to genital ridges, some primordial germ cells that have left the yolk sac endoderm migrate aberrantly cranially towards the diencephalic midline structures.[13][14][7][8][15][16][17]
Epidemiology and Demographics
The peak of germinoma occurs at ages 15-19 years: the median age at diagnosis is 10-12 years. CNS germ cell tumors commonly affects individuals between birth and 34 years of age. Males are more commonly affected with pineal germinona than females. The male to female ratio is approximately 5-22 to 1. Females are more commonly affected with suprasellar germinoma than males. The female to male ratio is approximately 1.3:1.
Risk Factors
There are no established risk factors for germinoma.
Screening
According to the United States Preventive Services Task Force, screening for extramammary Paget's disease is not recommended among the general population.[18]
Differential Diagnosis
Germinoma must be differentiated from other lesions in the pineal and suprasellar region, such as glial tumors which include astrocytomas and gangliomas, granular cell tumor, hamartomas, xanthogranuloma, meningiomas, colloid cysts, craniopharyngioma, cysticercosis, metastatic cancer with unknown primary site, pineal tumors, and pituitary macroadenomas.[19]
Natural History, Complications, and Prognosis
If left untreated, more than 50% of patients may continue to suffer from endocrine abnormalities such as growth hormone deficiency, growth retardation, hypopituitarism, and hypothyroidism, and may require lifelong hormonal replacement therapy. Common complications of germinoma include secondary cancers such as acute myeloid leukemia and radiation-induced brain neoplasms. Prognosis is generally excellent for germinomas, and the 5-year survival rate of patients with germinoma is approximately 70-90%. However, prognosis in general depends on the histological diagnosis and staging of the extent of disease.
Diagnosis
Staging
There is no established system for the staging of germ cell tumors, and most investigators utilize the TM system employed for staging medulloblastomas. Predominantly because of their midline location, staging for the size of the tumor at the time of diagnosis or after surgery (T-stage evaluation), has not been routinely employed in germ cell tumors.
History and Symptoms
gaze,,paralysis of convergence, diabetes insipidus, delayed pubertal development, precocious puberty, isolated growth hormone deficiency, hypopituitarism (central hypothyroidism, adrenal insufficiency), decreased visual acuity from chiasmic or optic nerve compression, and visual field deficit (e.g, bitemporal hemianopsia). Presenting symptoms of patients with intracranial GCTs depend upon the location, size of the tumor, and the patient's age.[20][21][22]
Physical Examination
Common physical examination findings of germinoma include paralysis of upward gaze, pupils nonreactive to light perception and accommodation or pupils which react better to accommodation than light, nystagmus, failure of convergence, lid retraction, papilledema, ataxia, and neurologic examination may be abnormal depending on the location of the tumor.
Laboratory Findings
An elevated concentration of AFP and beta-hCG in the serum and CSF, and CSF cytology to detect malignant cells is diagnostic of intracranial germ cell tumors. In patients in whom endoscopic biopsy is not considered possible, detection of elevated tumor markers may be sufficient for diagnosis.
Chest X Ray
Chest x-rays may be performed to detect metastases of germinoma to the lungs.
CT
Head and neck CT scan may be diagnostic of germinoma. Findings on CT scan suggestive of germinoma include hyperdensity compared to adjacent brain, pituitary stalk enhancement and thickening, and presence of calcification in the pineal region in the pediatric population.[19]
MRI
MRI of the brain and spine with and without gadolinium is the imaging modality of choice for germinoma. On MRI, intracranial GCTs appear isointense or hypointense on T1 sequences and hyperintense on T2 sequences.[19]
Ultrasound
On ultrasound, germinoma is characterized by heterogeneous echogenic mass with cystic and solid components.
Other Imaging Findings
Other diagnostic studies for germinoma include PET scan.[23]
Other Diagnostic Studies
Biopsy may be helpful in the diagnosis of germinoma. Findings on biopsy diagnostic of germinoma include undifferentiated, uniform large cells with abundant glycogen-rich cytoplasm arranged in nests separated by bands of connective tissue along trophoblastic lines.[24]
Treatment
Medical Therapy
Surgery
Primary Prevention
Secondary Prevention
References
- ↑ Template:Dorlands
- ↑ Louis, David N.; Ohgaki, Hiroko; Wiestler, Otmar D.; Cavenee, Webster K.; Burger, Peter C.; Jouvet, Anne; Scheithauer, Bernd W.; Kleihues, Paul (2007). "The 2007 WHO Classification of Tumours of the Central Nervous System". Acta Neuropathologica. 114 (2): 97–109. doi:10.1007/s00401-007-0243-4. ISSN 0001-6322.
- ↑ Jennings MT, Gelman R, Hochberg F (1985). "Intracranial germ-cell tumors: natural history and pathogenesis". J Neurosurg. 63 (2): 155–67. doi:10.3171/jns.1985.63.2.0155. PMID 2991485.
- ↑ Hoffman HJ, Otsubo H, Hendrick EB, Humphreys RP, Drake JM, Becker LE; et al. (1991). "Intracranial germ-cell tumors in children". J Neurosurg. 74 (4): 545–51. doi:10.3171/jns.1991.74.4.0545. PMID 1848284.
- ↑ Rickert CH, Simon R, Bergmann M, Dockhorn-Dworniczak B, Paulus W (2000). "Comparative genomic hybridization in pineal germ cell tumors". J Neuropathol Exp Neurol. 59 (9): 815–21. PMID 11005262.
- ↑ Schneider DT, Zahn S, Sievers S, Alemazkour K, Reifenberger G, Wiestler OD; et al. (2006). "Molecular genetic analysis of central nervous system germ cell tumors with comparative genomic hybridization". Mod Pathol. 19 (6): 864–73. doi:10.1038/modpathol.3800607. PMID 16607373.
- ↑ 7.0 7.1 Palmer RD, Foster NA, Vowler SL, Roberts I, Thornton CM, Hale JP; et al. (2007). "Malignant germ cell tumours of childhood: new associations of genomic imbalance". Br J Cancer. 96 (4): 667–76. doi:10.1038/sj.bjc.6603602. PMC 2360055. PMID 17285132.
- ↑ 8.0 8.1 Sato K, Takeuchi H, Kubota T (2009). "Pathology of intracranial germ cell tumors". Prog Neurol Surg. 23: 59–75. doi:10.1159/000210053. PMID 19329861.
- ↑ Kamakura Y, Hasegawa M, Minamoto T, Yamashita J, Fujisawa H (2006). "C-kit gene mutation: common and widely distributed in intracranial germinomas". J Neurosurg. 104 (3 Suppl): 173–80. doi:10.3171/ped.2006.104.3.173. PMID 16572634.
- ↑ Sakuma Y, Sakurai S, Oguni S, Satoh M, Hironaka M, Saito K (2004). "c-kit gene mutations in intracranial germinomas". Cancer Sci. 95 (9): 716–20. PMID 15471556.
- ↑ Wang HW, Wu YH, Hsieh JY, Liang ML, Chao ME, Liu DJ; et al. (2010). "Pediatric primary central nervous system germ cell tumors of different prognosis groups show characteristic miRNome traits and chromosome copy number variations". BMC Genomics. 11: 132. doi:10.1186/1471-2164-11-132. PMC 2837036. PMID 20178649.
- ↑ Terashima K, Yu A, Chow WY, Hsu WC, Chen P, Wong S; et al. (2014). "Genome-wide analysis of DNA copy number alterations and loss of heterozygosity in intracranial germ cell tumors". Pediatr Blood Cancer. 61 (4): 593–600. doi:10.1002/pbc.24833. PMID 24249158.
- ↑ Echevarría ME, Fangusaro J, Goldman S (2008). "Pediatric central nervous system germ cell tumors: a review". Oncologist. 13 (6): 690–9. doi:10.1634/theoncologist.2008-0037. PMID 18586924.
- ↑ Jubran RF, Finlay J (2005). "Central nervous system germ cell tumors: controversies in diagnosis and treatment". Oncology (Williston Park). 19 (6): 705–11, discussion 711-2, 715–7, 721. PMID 15971448.
- ↑ Pereda J, Motta PM (1991). "A unique fibrillar coat on the surface of migrating human primordial germ cells". Arch Histol Cytol. 54 (4): 419–25. PMID 1760220.
- ↑ Godin I, Wylie CC (1991). "TGF beta 1 inhibits proliferation and has a chemotropic effect on mouse primordial germ cells in culture". Development. 113 (4): 1451–7. PMID 1811953.
- ↑ Horowitz MB, Hall WA (1991). "Central nervous system germinomas. A review". Arch Neurol. 48 (6): 652–7. PMID 2039390.
- ↑ http://www.uspreventiveservicestaskforce.org/BrowseRec/Search?s=germinoma Accessed on January 26, 2016.
- ↑ 19.0 19.1 19.2 Germ cell tumors. Radiopedia(2015) http://radiopaedia.org/articles/central-nervous-system-germinoma Accessed on January 25, 2016
- ↑ Sethi RV, Marino R, Niemierko A, Tarbell NJ, Yock TI, MacDonald SM (2013). "Delayed diagnosis in children with intracranial germ cell tumors". J Pediatr. 163 (5): 1448–53. doi:10.1016/j.jpeds.2013.06.024. PMID 23896184.
- ↑ Packer RJ, Cohen BH, Cooney K, Coney K (2000). "Intracranial germ cell tumors". Oncologist. 5 (4): 312–20. PMID 10964999.
- ↑ Crawford JR, Santi MR, Vezina G, Myseros JS, Keating RF, LaFond DA; et al. (2007). "CNS germ cell tumor (CNSGCT) of childhood: presentation and delayed diagnosis". Neurology. 68 (20): 1668–73. doi:10.1212/01.wnl.0000261908.36803.ac. PMID 17502547.
- ↑ Okochi Y, Nihashi T, Fujii M, Kato K, Okada Y, Ando Y; et al. (2014). "Clinical use of (11)C-methionine and (18)F-FDG-PET for germinoma in central nervous system". Ann Nucl Med. 28 (2): 94–102. doi:10.1007/s12149-013-0787-4. PMC 3926980. PMID 24272066.
- ↑ Shibamoto Y (2009). "Management of central nervous system germinoma: proposal for a modern strategy". Prog Neurol Surg. 23: 119–29. doi:10.1159/000210058. PMID 19329866.