Germ cells, or gametes, are a type of cell responsible for sexual reproduction. They get their name from the word germinate, which means “to begin to grow.” They can develop into either sperm or egg cells, depending on the baby’s sex.
As the baby develops in the womb, germ cells move into place and turn either into eggs or sperm. However, sometimes a group of germ cells can experience abnormal growth and form a tumor. These germ cell tumors typically form in the ovaries or testicles, however in some rare cases they can develop in other parts of the body.
Germ cell tumors are typically very rare, and usually occur in adolescents and young adults. Patients who suffer from germ cell tumors are typically between the ages of 15 and 30, however, there are no rules, both children and adults can be diagnosed with it.
To help you get a better understanding of germ cell tumors, we have prepared a comprehensive guide to help you understand all of the different types of this disease and all of its symptoms and causes.
Types of Germ Cell Tumors
Germ cell tumors are a somewhat complex collection of tumors, and distinguishing them by type requires multiple different distinctions.
The first and most straightforward way we can differentiate germ cell tumors is into benign and malignant germ cell tumors, or in other words non-cancerous and cancerous.
The second distinction we can make is based on whether the patient is male or female. Male patients who suffer from a germ cell tumor could have a seminoma or a non-seminoma, both of which are testicular cancers. Female patients can suffer from dysgerminoma and non-dysgerminoma, which are both ovarian germ cell tumors.
And finally, we can distinguish a few more types of germ cell tumors:
- Teratoma, which can be benign teratoma (mature teratoma) and malignant teratoma (immature teratoma)
- Embryonal carcinoma
- Endodermal sinus tumor (yolk sac tumor)
- Mixed germ cell tumors
Extragonadal Germ Cell Tumor
Germ cell tumors typically manifest in the gonads, that is to say, the testicles or the ovaries. However, in some rare cases, a germ cell tumor may appear outside of these areas, which would make it extragonadal.
These tumors can be benign or malignant, and there are a couple of different types of extragonadal germ cell tumors:
- Mediastinal germ cell tumors
- Pineal germ cell tumors
- Retroperitoneal germ cell tumors
- Sacrococcygeal germ cell tumors
Germ Cell Tumor Causes and Risk Factors
- Genetic syndromes. There are certain genetic conditions that may increase the likelihood of developing a germ cell tumor, such as Turner syndrome and Klinefelter syndrome.
- Birth defects. A higher risk factor is often associated with birth factors related to the genitals, central nervous system, urinary tract, and spine.
- Cryptorchidism. In males, cryptorchidism, more commonly known as an undescended testicle, often leads to an increased chance of developing a germ cell tumor.
- Age. Even though germ cell tumors can appear at any age, they are most commonly found in certain age groups. Men typically develop a germ cell tumor between the ages of 15 and 35. For women, it can usually be found in adolescent girls and young women.
Germ Cell Tumor Symptoms
- Swollen abdomen with or without weight gain.
- Pelvic/ovarian pain, discomfort and tenderness.
- Painful cramping.
- Irregular vaginal bleeding.
- Difficulty eating followed by nausea.
Symptoms of Testicular Germ Cell Tumor
- Groin or abdominal pain.
- A firm and solid lump in the testicles that may or may not hurt and grows over time.
- A feeling of heaviness or pain in the scrotum.
- Back pain.
- An oddly misshapen testicle.
Symptoms of Extragonadal Germ Cell Tumor
If the germ cell tumor is found in the pelvis, it can cause issues with urination and bowel movements. If it’s in the lungs, patients often have trouble breathing. And if the patient has a germ cell tumor in their lower back, they experience weakness in their legs.
Germ Cell Tumor Diagnosis
If a person believes that they might have a germ cell tumor and are experiencing any of these symptoms, they need to seek medical attention immediately.
The first thing a doctor will do is perform a physical examination and talk to the patient about their medical history. This will allow the doctor to check for any physical symptoms the patient may be experiencing and see if there are any medical conditions that could indicate a higher risk factor for this or any other disease.
Afterward, they will perform the following tests:
- Imaging tests. Performing an imaging test is a crucial step in diagnosing any tumor because it allows the doctor to locate it and visualize it. In the case of germ cell tumors, CT scans are usually the most common imaging tests used because they provide detailed cross-sectional images of the entire body. However, the doctor may also choose to perform an MRI or ultrasound, depending on where the tumor is located.
- Blood tests. In some germ cell tumors, AFP and bHCG levels are increased, so a doctor may choose to check if this is the case with a blood test. A blood test is also done during a germ cell tumor diagnosis to check the blood counts and liver and kidney functions.
- Baseline hearing evaluation. This isn’t part of the diagnosis itself, however, the doctor may want to check the patient’s hearing before treatment and afterward to see if chemotherapy led to any hearing loss.
- Pulmonary function tests for lung evaluation. If the patient has a germ cell tumor in the lungs, pulmonary function tests may assist in making a diagnosis.
- Nuclear medicine GFR test for kidney assessment. Finally, if the patient is experiencing renal symptoms of germ cell tumor, the doctor will perform a kidney assessment with a nuclear medicine GFR test.
Germ Cell Tumor Staging
Once the doctor determines the presence of a germ cell tumor, before they proceed with the treatment, they also need to determine staging.
The staging will show to what extent the cancer has spread throughout the patient’s body. There are four stages in total, each of them with different symptoms.
- Stage 1 germ cell tumor. When the tumor is still in stage 1, it’s limited to the site where it originally originated and there is no sign that the tumor has spread. When the tumor is in this stage, it can usually be removed only with surgery.
- Stage 2 germ cell tumor. If the tumor is in stage 2, that means that it has spread from the original site, meaning the ovaries or testicles, and is now in nearby tissues or structures, but is still contained within the pelvis.
- Stage 3 germ cell tumor. When a germ cell tumor progresses to stage 3, it has spread to an area far from the original site and the gonad area. It often presents with regional lymph nodes.
- Stage 4 germ cell tumor. The final and most severe stage is stage 4, and if a patient is in this stage, their germ cell tumor has spread to distant tissues and organs. The most common sites of metastasis in stage 4 germ cell tumors are the liver, lungs and distant lymph nodes.
Germ Cell Tumor Treatment
After the doctor determines the presence of a germ cell tumor and its staging, they will take all of the necessary factors into consideration and come up with the best possible treatment plan.
There are three main treatments for a germ cell tumor:
Surgery. Surgery can be the only treatment if the tumor is small and in stage 1, and the first line of defense for more aggressive and advanced stages. During the procedure, a surgeon looks to remove the tumor and, if necessary, the affected testicle or ovary. Sometimes, they will be able to perform fertility-sparing surgery that will allow the patient to have children in the future.
Chemotherapy. If the tumor is too large to be removed via a surgical procedure or has spread to other parts of the body, chemotherapy will be the next step. Since germ cells are very sensitive to chemotherapy, this treatment option is often very effective. If the tumor is more aggressive, radiotherapy may be administered alongside chemotherapy.
Immunotherapy. In some cases, the best line of defense is to help improve the immune system and allow it to fight off the cancerous cells, which is done with immunotherapy. This treatment option is often used when the tumor has relapsed or when chemotherapy is unsuccessful.
Germ Cell Tumor Prognosis
The prognosis for patients suffering from a germ cell tumor greatly varies from one case to another and depends on several different factors. These factors include where the tumor is located, its stage at the time of diagnosis, the patient’s overall health and the efficacy of the chosen treatment.
That being said, germ cell tumors typically have an excellent prognosis. Testicular germ cell tumors have a survival rate of approximately 95%, and for ovarian tumors it’s around 93%.
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