Mediastinal germ cell tumor
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Maria Fernanda Villarreal, M.D. [2]
Synonyms and keywords: M-GCTs;
Overview
Mediastinal germ cell tumor is a extragonadal tumor derived from germ cell remnants in the mediastinum and a cause of anterior mediastinal mass.[1][2] Malignant germ cell tumors of the mediastinum are uncommon, representing only 3 to 10% of tumors originating in the mediastinum.
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:
- Loss of 1p, 4q, and 6q
- Gain of 1q, 3, and 20q
- 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
- Mediastinal germ cell tumor may be caused by either [cause1], [cause2], or [cause3].
- Mediastinal germ cell tumor is caused by a mutation in the [gene1], [gene2], or [gene3] gene[s].
- There are no established causes for mediastinal germ cell tumor.
Differentiating mediastinal germ cell tumor from other Diseases
- Mediastinal germ cell tumor must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
- [Differential dx1]
- [Differential dx2]
- [Differential dx3]
Epidemiology and Demographics
- Malignant germ cell tumors of the mediastinum are uncommon
- Malignant germ cell tumors represent only 3 to 10% of tumors originating in the mediastinum
Age
- Patients of all age groups may develop mediastinal germ cell tumor.
- Mediastinal germ cell tumor is more commonly observed among patients aged [age range] years old.
- Mediastinal germ cell tumor is more commonly observed among [elderly patients/young patients/children].
Gender
- Mediastinal germ cell tumor affects men and women equally.
- [Gender 1] are more commonly affected with mediastinal germ cell tumor than [gender 2].
- The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.
Race
- There is no racial predilection for mediastinal germ cell tumor.
Risk Factors
- Common risk factors in the development of mediastinal germ cell tumor, include:
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 [manifestation 1], [manifestation 2], and [manifestation 3].
- If left untreated, [#%] of patients with mediastinal germ cell tumor may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
- The most common complications of mediastinal germ cell tumor is superior vena cava syndrome.
- Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with mediastinal germ cell tumor is approximately [#%].
Diagnosis
Diagnostic Criteria
- The diagnosis of mediastinal germ cell tumor is made when at least [number] of the following [number] diagnostic criteria are met:
- [criterion 1]
- [criterion 2]
- [criterion 3]
- [criterion 4]
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
- Superior vena cava syndrome
- 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 [diagnostic study name].
- Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].
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 [duration]. Follow-up testing includes [test 1], [test 2], and [test 3].
References
- ↑ Alan Sandler (1997). "Mediastinal Germ Cell Tumors". Semin Respir Crit Care Med. 18 (4): 383-392. doi:10.1055/s-2007-1009353.
- ↑ "Mediastinal Germ Cell Tumor Imaging".