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| __NOTOC__
| | #REDIRECT [[Mediastinal mass differential diagnosis]] |
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| {{CMG}} {{AE}} {{MV}}
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| {{SK}} M-GCTs; Malignant germ cell tumors of the mediastinum;
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| ==Overview==
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| '''Mediastinal germ cell tumor''' is a extragonadal [[tumor]] derived from [[germ cell]] remnants in the [[mediastinum]] and a cause of anterior mediastinal mass.<ref>{{Cite journal | author = Alan Sandler| year = 1997 | url = https://www.thieme-connect.com/ejournals/abstract/10.1055/s-2007-1009353 | title = Mediastinal Germ Cell Tumors| journal = Semin Respir Crit Care Med| volume = 18| issue=4 | page = 383-392 | doi=10.1055/s-2007-1009353}}</ref><ref>{{Cite web|url=http://emedicine.medscape.com/article/359110-overview| title=Mediastinal Germ Cell Tumor Imaging }}</ref> Malignant germ cell tumors of the mediastinum are uncommon, representing only 3 to 10% of tumors originating in the mediastinum. Mediastinal germ cell tumor arises from germ cells, which are normally involved in the formation of the gametes. The pathogenesis of mediastinal germ cell tumor is characterized by the abnormal migration of germ cells during embryogenesis. The most common cause of mediastinal germ cell tumor is teratoma. Other causes of mediastinal germ cell tumor, include: embryonal cell carcinoma, [[choriocarcinoma]], [[yolk sac tumor]], mixed germ cell tumor. Mediastinal germ cell tumor is more commonly observed among male patients between 15 to 30 years old. The most common risk factor in the development of mediastinal germ cell tumor is [[Klinefelter's syndrome|Klinefelter syndrome]] (47XXY). The majority of patients with mediastinal germ cell tumor are usually symptomatic at the time of diagnosis. Early clinical features include [[chest pain]], [[dyspnea]], and [[cough]]. The diagnosis of a mediastinal germ cell tumor should be considered in all young males with a mediastinal mass. [[Chemotherapy regimen|Cisplatin-based chemotherapy]] is the medical treatment of choice for mediastinal germ cell tumors. Radical resection in conjunction with chemotherapy/radiation is the most common approach to the treatment of mediastinal germ cell tumor.
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| ==Historical Perspective==
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| *Mediastinal germ cell tumor was first described by Friedman in 1951.
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| ==Classification==
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| *Mediastinal germ cell tumor may be classified according to histopathological subtype in 2 groups:
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| :*[[Seminoma]]
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| :*Non-seminomatous germ cell tumours (NSGCT)
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| ::*Embryonal cell carcinoma
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| ::*Choriocarcinoma
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| ::*Yolk sac tumor
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| ::*[[Teratoma]] (most common)
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| ::*Mixed germ cell tumor
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| ==Pathophysiology==
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| *The pathogenesis of mediastinal germ cell tumor is characterized by the abnormal migration of germ cells.
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| *Mediastinal germ cell tumor arises from germ cells, which are normally involved in the formation of the gametes.
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| *Genetic mutations associated with the development of mediastinal germ cell tumor, include:<ref name="pmid11921289">{{cite journal |vauthors=Schneider DT, Schuster AE, Fritsch MK, Calaminus G, Göbel U, Harms D, Lauer S, Olson T, Perlman EJ |title=Genetic analysis of mediastinal nonseminomatous germ cell tumors in children and adolescents |journal=Genes Chromosomes Cancer |volume=34 |issue=1 |pages=115–25 |year=2002 |pmid=11921289 |doi= |url=}}</ref>
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| :*Sex chromosomal abnormalities
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| ::*Loss of 1p, 4q, and 6q
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| ::*Gain of 1q, 3, and 20q
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| :*[[CCND2]]
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| :*p14ARF
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| *On gross pathology, findings of mediastinal germ cell tumor may include:
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| :*Unencapsulated
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| :*Homogenous fleshy mass with indistinct boundaries
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| :*Large size (20 to 30 cm)
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| :*Invasion of adjacent structures
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| *On microscopic histopathological analysis findings of mediastinal germ cell tumor, include:
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| :*Large tumor cells with clear cytoplasm
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| :*Prominent nucleoli
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| ==Causes==
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| *The most common cause of mediastinal germ cell tumor is teratoma.
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| *Other causes of mediastinal germ cell tumor, include:
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| :*Embryonal cell carcinoma
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| :*Choriocarcinoma
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| :*Yolk sac tumour
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| :*Mixed germ cell tumour
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| ==Differentiating Mediastinal Germ Cell Tumor from Other Diseases==
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| *Mediastinal germ cell tumor must be differentiated from other diseases that cause chest pain, [clinical feature 2], and [clinical feature 3], such as:
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| :*[[Lymphoma|Lymphomas]]
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| :*[[Soft tissue sarcoma]]
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| :*[[Thymoma]]
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| :*[[Neurogenic tumor|Neurogenic tumors]]
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| ==Epidemiology and Demographics==
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| *Mediastinal germ cell tumor are uncommon
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| *Mediastinal germ cell tumor represent only 3 to 10% of tumors originating in the mediastinum
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| ===Age===
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| *Mediastinal germ cell tumor is more commonly observed among young adults.
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| *Mediastinal germ cell tumor is more commonly observed among patients between 15 to 30 years old.
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| ===Gender===
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| *Mediastinal germ cell tumor affects men and women equally.
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| *Males are more commonly affected with mediastinal germ cell tumor than females.
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| ===Race===
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| *There is no racial predilection for mediastinal germ cell tumor.
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| ==Risk Factors==
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| *The most common risk factor in the development of mediastinal germ cell tumor is Klinefelter syndrome (47XXY).
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| == Natural History, Complications and Prognosis==
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| *The majority of patients with malignant mediastinal germ cell tumor are usually symptomatic at the time of diagnosis
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| *Early clinical features include chest pain, dyspnea, and cough.
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| *If left untreated, the majority of patients with mediastinal germ cell tumor may progress to develop metastasis, malignant pleural effusion, and respiratory failure.
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| *The most common complication of mediastinal germ cell tumor is superior vena cava syndrome.
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| *Prognosis is generally poor, and the median survival rate of patients with mediastinal germ cell tumor is approximately 5 months.<ref name="pmid8494705">{{cite journal |vauthors=Childs WJ, Goldstraw P, Nicholls JE, Dearnaley DP, Horwich A |title=Primary malignant mediastinal germ cell tumours: improved prognosis with platinum-based chemotherapy and surgery |journal=Br. J. Cancer |volume=67 |issue=5 |pages=1098–101 |year=1993 |pmid=8494705 |pmc=1968447 |doi= |url=}}</ref>
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| == Diagnosis ==
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| ===Diagnostic Criteria===
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| *The diagnosis of mediastinal germ cell tumor is made with the following diagnostic criteria:
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| :*Hormone production (e.g. [[beta-HCG]], [[AFP]])
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| :*No evidence of a primary tumor in the testes or ovaries
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| :*Anterior mediastinal mass
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| === Symptoms ===
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| *Mediastinal germ cell tumors are usually asymptomatic and found incidentally.
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| *Symptoms of mediastinal germ cell tumor may include the following:
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| :*[[Chest pain]]
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| :*[[Dyspnea]]
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| :*[[Cough]]
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| :*[[Weight loss]]
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| :*[[Fever]]
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| :*[[Nausea]]
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| === Physical Examination ===
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| *Patients with mediastinal germ cell tumor usually are well-appearing.
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| *Physical examination may be remarkable for:<ref name="pmid8494705">{{cite journal |vauthors=Childs WJ, Goldstraw P, Nicholls JE, Dearnaley DP, Horwich A |title=Primary malignant mediastinal germ cell tumours: improved prognosis with platinum-based chemotherapy and surgery |journal=Br. J. Cancer |volume=67 |issue=5 |pages=1098–101 |year=1993 |pmid=8494705 |pmc=1968447 |doi= |url=}}</ref>
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| :*Dull percussion
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| :*Tactile fremitus
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| :*Reduced chest expansion
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| :*Crackling or bubbling noises
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| :*Present whispered pectoriloquy
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| === Laboratory Findings ===
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| *Laboratory findings consistent with the diagnosis of mediastinal germ cell tumor, include:<ref name="pmid8494705">{{cite journal |vauthors=Childs WJ, Goldstraw P, Nicholls JE, Dearnaley DP, Horwich A |title=Primary malignant mediastinal germ cell tumours: improved prognosis with platinum-based chemotherapy and surgery |journal=Br. J. Cancer |volume=67 |issue=5 |pages=1098–101 |year=1993 |pmid=8494705 |pmc=1968447 |doi= |url=}}</ref>
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| :*Elevation in serum [[alpha-fetoprotein]] (AFP)
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| :*Elevation in [[beta-human chorionic gonadotropin]] (beta-hCG)
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| ===Imaging Findings===
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| *Chest radiography is the initial imaging modality of choice for mediastinal germ cell tumor.
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| *On chest radiography, findings of mediastinal germ cell tumor, include:<ref name="pmid8494705">{{cite journal |vauthors=Childs WJ, Goldstraw P, Nicholls JE, Dearnaley DP, Horwich A |title=Primary malignant mediastinal germ cell tumours: improved prognosis with platinum-based chemotherapy and surgery |journal=Br. J. Cancer |volume=67 |issue=5 |pages=1098–101 |year=1993 |pmid=8494705 |pmc=1968447 |doi= |url=}}</ref>
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| :*Displaced anterior junction line
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| :*Obliterated cardiophrenic angles
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| :*Obtuse angles with the mediastinum
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| :*Obliterated retrosternal clear space
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| :*Effacement/ dense ascending aorta
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| *On chest radiography, signs of mediastinal germ cell tumor, include:
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| :*'''Hilum Overlay Sign''': hilar vessels through the mass (the mass does not arise from the hilum)
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| *On CT, findings of mediastinal germ cell tumor, include:
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| :*Anterior mediastinal mass
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| :*Obtuse angles with the mediastinum
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| :*Enhancing septations
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| The image below demonstrates a case of mediastinal germ cell tumor
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| <gallery>
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| <div align="left">
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| <gallery heights="175" widths="175">
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| Image:Germ-cell-tumor-001.jpg|CT shows a mediastinal germ cell tumor.
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| Image:Germ-cell-tumor-002.jpg|CT shows a mediastinal germ cell tumor.
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| Image: Germ cell tumor .jpg| CT scan: mediastinal germ cell tumor.
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| </gallery>
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| === Other Diagnostic Studies ===
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| *Mediastinal germ cell tumor may also be diagnosed using positron emission tomography.
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| *Findings on positron emission tomography, include:
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| :*Useful to rule out the involvement of thyroid tissue.
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| == Treatment ==
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| === Medical Therapy ===
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| *Cisplatin-based chemotherapy is the medical treatment of choice for mediastinal germ cell tumors.
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| *Treatment selection depends on disease stage and size of mediastinal tumor.
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| *Common therapies for mediastinal germ cell tumor, include:<ref name="treat> Extragonadal Germ Cell Tumors Treatment–Health Professional Version (PDQ®) http://www.cancer.gov/types/extragonadal-germ-cell/hp/extragonadal-treatment-pdq Accessed on April 14, 2016 </ref>
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| :*[[Etoposide]]
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| :*[[Ifosfamide]]
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| :*[[Cisplatin]]
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| :*[[Bleomycin]]
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| *Mediastinal germ cell tumors are highly sensitive to radiation therapy and to combination chemotherapy.
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| *Alternative treatment for mediastinal germ cell tumor, include:<ref name="treat> Extragonadal Germ Cell Tumors Treatment–Health Professional Version (PDQ®) http://www.cancer.gov/types/extragonadal-germ-cell/hp/extragonadal-treatment-pdq Accessed on April 14, 2016 </ref>
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| :*Primary radiotherapy in the absence of metastatic disease
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| === Surgery ===
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| *Surgery is the mainstay of therapy for mediastinal germ cell tumor.<ref name="treat> Extragonadal Germ Cell Tumors Treatment–Health Professional Version (PDQ®) http://www.cancer.gov/types/extragonadal-germ-cell/hp/extragonadal-treatment-pdq Accessed on April 14, 2016 </ref>
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| * Small mediastinal germ cell tumor (usually asymptomatic) should undergo thoracotomy and attempted complete resection.
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| * Radical resection in conjunction with chemotherapy/radiation is the most common approach to the treatment of mediastinal germ cell tumor.
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| === Prevention ===
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| *There are no primary preventive measures available for mediastinal germ cell tumor.
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| *Once diagnosed and successfully treated, patients with mediastinal germ cell tumor are followed-up every year.
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| *Follow-up testing for mediastinal germ cell tumor, includes chest radiography and tumoral biomarkers.
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| ==References==
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| {{Reflist|2}}
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| [[Category: Oncology]]
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| [[Category:Up-To-Date]]
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| [[Category:Oncology]]
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| [[Category:Medicine]]
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| [[Category:Gynecology]]
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| [[Category:Surgery]]
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| [[Category:Pulmonology]]
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