Mediastinal germ cell tumor: Difference between revisions

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#REDIRECT [[Mediastinal mass differential diagnosis]]
{{SI}}                                                                 
{{CMG}} {{AE}} {{MV}}
{{SK}} M-GCTs; Malignant germ cell tumors of the mediastinum;
==Overview==
 
'''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. 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.
 
==Historical Perspective==
*Mediastinal germ cell tumor was first discovered by [scientist name], a [nationality + occupation], in [year] during/following [event].
*In [year], [gene] mutations were first identified in the pathogenesis of mediastinal germ cell tumor.
*In [year], the first [discovery] was developed by [scientist] to treat/diagnose mediastinal germ cell tumor.
==Classification==
*Mediastinal germ cell tumor may be classified according to histopathological subtype in 2 groups:
:*Seminoma
:*Non-seminomatous germ cell tumours (NSGCT)
::*Embryonal cell carcinoma
::*Choriocarcinoma
::*Yolk sac tumour
::*Teratoma (most common)
::*Mixed germ cell tumor
==Pathophysiology==
*The pathogenesis of mediastinal germ cell tumor is characterized by the abnormal migration of germ cells during embryogenesis.
*Mediastinal germ cell tumor arises from germ cells, which are normally involved in the formation of o the gametes.
*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>
:*Sex chromosomal abnormalities
::*Loss of 1p, 4q, and 6q
::*Gain of 1q, 3, and 20q
:*CCND2 gene
:*p14ARF gene
*On gross pathology,  findings of mediastinal germ cell tumor may include:
:*Unencapsulated
:*Homogenous fleshy mass with indistinct boundaries
:*Invasion of adjacent structures
*On microscopic histopathological analysis  findings of mediastinal germ cell tumor, include:
:*Large tumor cells with clear cytoplasm
:*Prominent nucleoli
 
==Causes==
*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 tumour
:*Mixed germ cell tumour
 
==Differentiating Mediastinal Germ Cell Tumor from Other Diseases==
*Mediastinal germ cell tumor must be differentiated from other diseases that cause chest pain, [clinical feature 2], and [clinical feature 3], such as:
:*Lymphomas
:*Soft tissue sarcoma
:*Thymoma
:*Neurogenic tumors
 
==Epidemiology and Demographics==
*Mediastinal germ cell tumor are uncommon
*Mediastinal germ cell tumor represent only 3 to 10% of tumors originating in the mediastinum
 
===Age===
*Mediastinal germ cell tumor is more commonly observed among young adults.
*Mediastinal germ cell tumor is more commonly observed among patients between 15 to 30 years old.
 
===Gender===
*Mediastinal germ cell tumor affects men and women equally.
*Males are more commonly affected with mediastinal germ cell tumor than females.
 
===Race===
*There is no racial predilection for mediastinal germ cell tumor.
 
==Risk Factors==
*The most common risk factor in the development of mediastinal germ cell tumor is Klinefelter syndrome (47XXY).
 
== Natural History, Complications and Prognosis==
*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.
*If left untreated, the majority of patients with mediastinal germ cell tumor may progress to develop metastasis, malignant pleural effusion, and respiratory failure.
*The most common complication of mediastinal germ cell tumor is superior vena cava syndrome.
*Prognosis is generally poor, and the median survival rate of patients with mediastinal germ cell tumor is approximately 5 months.
 
== Diagnosis ==
===Diagnostic Criteria===
*The diagnosis of mediastinal germ cell tumor is made with the following diagnostic criteria:
:*Hormone production (e.g. beta-HCG, AFP)
:*No evidence of a primary tumor in the testes or ovaries
:*Anterior mediastinal mass  
:*Obtuse angles with the lung
 
=== Symptoms ===
*Mediastinal germ cell tumors are usually asymptomatic and found incidentally.
*Symptoms of mediastinal germ cell tumor may include the following:
:*Chest pain
:*Dyspnea
:*Cough
:*Weight loss
:*Fever
:*Nausea
=== Physical Examination ===
*Patients with mediastinal germ cell tumor usually are well-appearing.
*Physical examination may be remarkable for:
:*Dull percussion
:*Tactile fremitus
:*Reduced chest expansion
:*Crackling or bubbling noises
:*Present whispered pectoriloquy
 
=== Laboratory Findings ===
*Laboratory findings consistent with the diagnosis of mediastinal germ cell tumor, include:
:*Elevation in serum alpha-fetoprotein (AFP)
:*Elevation in beta-human chorionic gonadotropin (beta-hCG)
 
===Imaging Findings===
*Chest radiography is the initial imaging modality of choice for mediastinal germ cell tumor.
*On chest radiography, findings of mediastinal germ cell tumor, include:
:*Displaced anterior junction line
:*Obliterated cardiophrenic angles
:*Obtuse angles with the mediastinum
:*Obliterated retrosternal clear space
:*Effacement/ dense ascending aorta
*On chest radiography, signs of mediastinal germ cell tumor, include:
:*'''Hilum Overlay Sign''': hilar vessels through the mass (the mass does not arise from the hilum)
*On CT, findings of mediastinal germ cell tumor, include:
:*Anterior mediastinal mass
:*Obtuse angles with the mediastinum
:*Enhancing septations
 
=== Other Diagnostic Studies ===
*Mediastinal germ cell tumor may also be diagnosed using positron emission tomography.
*Findings on positron emission tomography,  include:
:*Useful to rule out the involvement of thyroid tissue.
== Treatment ==
=== Medical Therapy ===
*Cisplatin-based chemotherapy is the treatment of choice for mediastinal germ cell tumors.
*Common therapies for mediastinal germ cell tumor, include:
:*Etoposide
:*Ifosfamide
:*Cisplatin
:*Bleomycin
*Alternative treatment for mediastinal germ cell tumor, include:
:*Primary radiotherapy in the absence of metastatic disease
 
=== Surgery ===
*Surgery is the mainstay of therapy for mediastinal germ cell tumor.
* Radical resection in conjunction with chemotherapy/radiation is the most common approach to the treatment of mediastinal germ cell tumor.
 
=== Prevention ===
*There are no primary preventive measures available for mediastinal germ cell tumor.
*Once diagnosed and successfully treated, patients with mediastinal germ cell tumor are followed-up every year.
*Follow-up testing for mediastinal germ cell tumor, includes chest radiography and tumoral biomarkers.
 
==References==
{{Reflist|2}}
[[Category: Oncology]]

Latest revision as of 17:25, 19 February 2019