What Is Malignant Germ Cell Tumor?
Malignant germ cell tumors are the cancerous growths of neoplastic cells that form from the reproductive germ cells. Most malignant germ cell tumors form in the testicles or ovaries. The germ cells are the cells that are developed in the fetus and form the reproductive system in males and females. After development, these germ cells pass through the midline pathway within the body and descend as either ovarian cells or testicular cells into the pelvis and into the scrotal sac respectively. Hence, most ovarian and testicular tumors derive their origin from germ cells. The ovaries and testes are known as gonads.
The tumors that are located outside the gonads are called extragonadal sites. The malignant tumor cells can also occur through the midline pathway and can also be usually present in the brain, chest, abdomen, pelvis, and lower back area.
Malignant germ cell tumors are rare cancerous tumors usually occurring in children and young adults who are below twenty years of age. Malignant germ cell tumors have the potential to metastasize (spread) to other organs of the body. The most common metastatic sites include the lungs, liver, bones, bone marrow, lymph nodes, and brain. Rarely, malignant germ cell tumors can metastasize to other body organs.
What Is the Cause of Malignant Germ Cell Tumors?
Mutations in the genes of a germ cell can cause uncontrolled growth of the tumor cells which leads to a tumor. The risk factors that can cause the cells to grow out of control include:
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Undescended one or both testicles that did not drop into the scrotum.
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Abnormalities at the time of birth in the central nervous system, gonads, lower back, genitals, lower spine, and urinary tract.
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Genetic disorders like Klinefelter syndrome or Turner syndrome are where the affected person has either an extra or missing sex chromosome.
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A hereditary disorder affecting other members of the family.
Malignant germ cell tumors were first reported as a clinical entity approximately fifty years ago. Germ cell tumors that are extragonadal were earlier considered to be isolated metastases from a primary gonadal site. However, it is now substantiated that these tumors have an extragonadal origin. The extragonadal germ cell tumors that particularly arise in the mediastinal (chest area) and pineal sites (in the midline of the brain) undergo a malignant transformation of germinal cells that are distributed to these sites and can develop in the absence of a primary germ cell tumor in the gonad. Some scientists believe that this sporadic distribution occurs as a result of germ cell migration abnormally during embryogenesis. Other scientists suggest an extensive distribution of germ cells to various sites during the normal process of embryogenesis, with these cells transferring genetic information at somatic sites (head, neck, shoulders, and abdomen).
What Are the Types of Malignant Germ Cell Tumors?
Malignant germ cell tumors are mainly divided into two main groups:
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Seminomas - Seminoma germ cell tumors are known as dysgerminomas in females).
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Non-Seminoma - Non-seminoma germ cell tumors are known as non-dysgerminomas in females.
Malignant Non-Seminoma tumors include:
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Immature teratomas.
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Yolk sac tumors.
Some non-seminoma malignant tumors develop from a single type of cell. And a few of them develop from a mixture of various cell types. So, for instance, a tumor can be a mixture of a few teratoma cells and a few embryonal carcinoma tumor cells.
Seminoma malignant germ cell tumors are occasionally called pure seminomas. They contain a single type of cell only. However, some malignant germ cell tumors comprise both seminoma tumor cells and non-seminoma cells. Healthcare professionals usually regard these tumors as non-seminoma tumors and treat them accordingly.
What Are the Clinical Features of Malignant Germ Cell Tumors?
Malignant germ cell tumors are usually symptomatic, unlike benign ones and cause signs and symptoms related to the compression or invasion (metastasis) of surrounding structures such as the lungs, pleura, pericardium, and chest wall. Pure seminomas are slow-growing tumors and are less aggressive in nature. They are less potent for metastasis in the early stages than non-seminomatous malignant tumors.
What Are Seminomas?
Seminomas are relatively slow-growing tumors and usually enlarge rapidly before showing symptoms. Tumors that are of a size of 20 to 30 centimeters in diameter usually do not show enough signs and symptoms. Pressure sensation or dull aching chest pain is usually the most common presenting symptom. Exertional difficulty breathing, cough, difficulty in swallowing, and hoarseness are some of the additional symptoms. Superior vena cava syndrome (signs and symptoms arising due to partial or complete blockage of the blood flow by superior vena cava) is found to develop in about ten percent of patients.
Only about 30 to 40 percent of patients having mediastinal seminomas have localized disease. The remaining tumors have one or more distant metastatic sites. The lungs, pleura, and pericardium are the most common sites for metastasis. The skeletal system is the most commonly involved metastatic site present in the extrathoracic site. The potential of testicular seminoma to spread to bone has also been identified.
What Are Non-Seminomas?
Non-seminomas are rapidly growing tumors that are usually symptomatic. The presenting symptoms are much more frequent. Common metastatic sites of the tumors include the lungs, pleura, supraclavicular and retroperitoneal lymph nodes, and liver. Less commonly involved sites include the bone, brain, and kidneys. Some people exhibit signs of gynecomastia. Choriocarcinomas have a marked uncontrolled bleeding tendency. The prodromal symptoms include weight loss, lethargy, weakness, and high temperature. These symptoms are more common in non-seminoma tumor patients than in those having pure seminomas.
How Do Healthcare Providers Diagnose Malignant Germ Cell Tumors?
Certain diagnostic tests are required to diagnose the disease. These include:
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Pelvic Examination - To check the size and extent of the tumor.
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Laparoscopy - A procedure that uses small cuts to detect the tumor.
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Ultrasound - To scan images of the male and female reproductive organs.
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Computed Tomography - To scan detailed images of the reproductive organs.
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Serum Tumor Marker Test - It is a blood test to assess the levels of certain substances in the body. Increased levels of alpha-fetoprotein (AFP), or human chorionic gonadotropin (HCG) can be signs of malignant germ cell tumors.
What Is the Treatment of Malignant Germ Cell Tumors?
The mainstay of treatment is surgery and chemotherapy.
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Surgery - Surgery is usually required to remove malignant germ cell tumors.
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Chemotherapy - Chemotherapy is generally required after surgery. Even cancers that have metastasized are treatable with chemotherapy.
How to Cope With Malignant Germ Cell Tumors?
Coping with a malignant tumor like this can be very difficult. Knowing about this rare neoplasm and its treatment can help the patient to make decisions and cope with the situation. Talking to other people who are suffering from the same disease can help to relieve stress. Performing meditation and spending time in nature can help the person cope with his mental stress.
Conclusion:
Malignant germ cell tumors are rare neoplasms. One should immediately visit the doctor if warning signs are noticed. Early diagnosis and treatment improve the prognosis of malignant germ cell tumors in the affected individuals.
