Embryonal carcinomas are a rare type of cancer that develops from germ cellsa cell that develops into reproductive cells (eggs in females, sperm in males). In most cases, embryonal carcinomas develop in the testicles – however they can develop in other places.
Germ cell tumours are a rare group of neoplasms that arise from primordial germ cells – the cells responsible for developing into reproductive cells (gametes) such as ovum and sperm. These tumours typically originate in the gonads, which are the organs that produce gametes (ovaries in females and the testicles in males). These tumours are referred to as gonadal germ cell tumours. In some cases, germ cells can migrate to other parts of the body during early embryonic development, leading to tumour formation outside of the gonads later in life. These are known as extragonadal germ cell tumours, and are most commonly found in the brain, mediastinum, retroperitoneum, or sacrococcygeal region.
In some cases, embryonal carcinomas can increase the levels of human chorionic gonadotropin (HCG), which is a hormone produced by the placenta (an organ that develops alongside a fetus during pregnancy) during early stages of pregnancy. Additionally, embryonal carcinomas can increase the levels of alpha-fetoprotein (AFP), which is a hormone produced by the liver that is responsible for transporting heavy metal ions in fetal blood during the early stages of pregnancy.
Embryonal carcinomas are generally more common in males, with the average age of diagnosis varying between subtypes. However, anyone can get this disease.
Types of Embryonal Carcinoma
Embryonal carcinomas can be classified by their location within the body.
Gonadal Embryonal Carcinoma
Gonadal embryonal carcinomas are more common, and develop in either the ovaries or testicles.
Ovarian Embryonal Carcinoma
Ovarian embryonal carcinomas are a rare type of germ-cell tumour, and often present as a part of a mixed germ-cell tumour (a cancer containing cells from different germ-cell tumours). It is most commonly found in female adolescents and young adults with an average age of diagnosis around 14-15 years old. Ovarian embryonal carcinomas are often aggressive, and may not have as good of a prognosisto predict how a disease/condition may progress and what the outcome might be as other types of embryonal carcinomas.
Testicular Embryonal Carcinoma
Testicular embryonal carcinomacancer arising from tissues that line organs is the most common type of embryonal carcinoma, and can present as a part of a mixed germ-cell tumour. It is most commonly found in young adult males between the ages of 25-35. While testicular embryonal carcinoma can be aggressive, it can have a good prognosis when found early.
Extragonadal Embryonal Carcinoma
Extragonadal embryonal carcinomas are much less common than gonadal embryonal carcinomas, and develop in areas other than the gonads.
Intracranial Embryonal Carcinoma
Intracranial embryonal carcinomas are a rare type of germ-cell tumour that develops in the brain, most commonly in midline structures such as pineal region, suprasellar region, hypothalamus and third ventricle of the brain. It is most commonly found between the ages of 10-30, however patients presenting outside of this age range have been reported. Intracranial embryonal carcinomas are often aggressive, and may not have as good of a prognosis as other types of embryonal carcinomas.
Mediastinal Embryonal Carcinoma
Mediastinal embryonal carcinomas are a rare type of germ-cell tumour that develops in the mediastinum, most commonly the anterior mediastinum. It is most commonly found in males between the ages of 20-40. Mediastinal embryonal carcinomas are often aggressive, and may not have as good of a prognosis as other types of embryonal carcinomas.
Rare Extragonadal Embryonal Carcinoma
These types of embryonal carcinomas are considered to be very rare:
- Retroperitoneal embryonal carcinoma.
- Sacrococcygeal embryonal carcinoma.
Treatment
If an embryonal carcinoma is detected, it will be staged and graded based on size, metastasis, and how the cancer cells look under the microscope. Staging and grading help your doctors determine the best treatment for you.
FIGO Staging System – Ovarian Embryonal Carcinomas
Ovarian cancers can be staged using the Federation of Gynaecology and Obstetrics (FIGO) system from stage I to IV:
- Stage I: cancer cells are confined to one or both ovaries only. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby organs in the pelvis, such as the uterus, fallopian tubes, bladder and/or bowel. This is also known as localised cancer.
- Stage III: the cancer has become larger and has spread beyond the pelvis into the lining of the abdomen (peritoneum). Lymph nodes are also often affected. This is also known as advanced or metastatic cancer.
- Stage IV: the cancer has spread to more distant organs, such as the lungs or the liver. This is also known as advancedat a late stage, far along or metastatic cancer.
TMN Staging System
All other embryonal carcinomas can be staged using the TNM staging system:
- T (tumour) indicates the size and depth of the tumour.
- N (node) indicates whether the cancer has spread to nearby lymph nodessmall bean-shaped structures that filters harmful substances from lymph fluid.
- M (metastasis) indicates whether the cancer has spread to other parts of the body.
This system can also be used in combination with a numerical value, from stage 0-IV:
- Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissue.
- Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and had not spread to lymph nodes. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localised cancer.
- Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also known as localised cancer.
- Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advanced or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Grade I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
Once your tumour has been staged and graded, your doctor may recommend genetic testinga procedure that analyses DNA to identify changes in genes, chromosomes and proteins, which can be used to analyse tumour DNA to help determine which treatment has the greatest chance of success, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Treatment Options
Treatment is dependent on several factors, including location, age, stage of disease and overall health.
Treatment options for embryonal carcinomas may include:
- Surgery to remove as much of the tumour as possible – will vary based on tumour location.
- Chemotherapya cancer treatment that uses drugs to kill or slow the growth of cancer cells, while minimising damage to healthy cells.
- Radiation therapya treatment that uses controlled doses of radiation to damage or kill cancer cells (some types of embryonal carcinomas may be resistant to radiation therapy).
- Clinical trialsresearch studies performed to test new treatments, tests or procedures and evaluate their effectiveness on various diseases.
- Palliative carea variety of practices and exercises used to provide pain relief and improve quality of life without curing the disease.
Gonadal Embryonal Carcinoma Treatment and Fertility
Treatment for ovarian and testicular embryonal carcinomas may make it difficult to conceive a child. If fertility is important to you, discuss your options with your doctor and a fertility specialist prior to the commencement of treatment.
Risk factors
Because of how rare embryonal carcinomas are, there has been limited research done into the risk factors of this disease. However, a link has been found between the development of mediastinal germ cell tumours and males with the genetic disorder Klinefelter syndrome.
Symptoms
The symptoms of embryonal carcinoma will vary based on location.
Symptoms of Ovarian Embryonal Carcinoma
Symptoms of ovarian embryonal carcinoma may include:
- Precocious (early) puberty.
- Changes in menstrual periods, such as irregular periods, unusual vaginal bleeding, or vaginal bleeding post menopause.
- Unusual vaginal bleeding not associated with menstruation.
- Infertility.
- Amenorrhea.
- Mild hirsutism (growth of excessive male-pattern hair in women).
Symptoms of Testicular Embryonal Carcinoma
Symptoms of testicular embryonal carcinoma may include:
- A painless mass in the testicle(s).
- Changes in testicular size and/or shape.
- A feeling of heaviness and/or unevenness in the scrotum.
- Pain or discomfort in the testicle(s) and/or scrotum (less common).
- Aches in the lower abdomen, back and/or scrotum.
Symptoms of Intracranial Embryonal Carcinoma
Symptoms of intracranial embryonal carcinoma vary based on location.
Pinel Gland Region
- Hydrocephalusa build up of cerebrospinal fluid (CSF) in the brain, causing pressure and potentially damaging brain tissue, which carries its own set of symptoms:
- Headaches.
- Nausea and/or vomiting.
- Difficulties with eye movement.
- Difficulties with balance.
- Difficulties with walking.
- Fatigue.
- Memory problems.
- Seizures.
- Behavioural and/or cognitive changes.
- Vision changes, such as double vision and difficulty looking up.
Suprasellar region, hypothalamus or pituitary gland
- Irregular sleep.
- Early puberty in children.
- Delayed puberty in children.
- Stunted growth in children.
- Changes in eyesight, such as loss of peripheral vision or loss of vision.
- Diabetes insipidus (disorder causing fluid imbalance in the body), which carries its own set of symptoms:
- Polyuriafrequent urination.
- Intense thirst.
- Isolated growth hormone deficiency, which carries its own set of symptoms:
- Poor growth.
- Impaired hair and/or nail growth.
- Delayed development of teeth.
- Delayed puberty.
- Hypoglycaemialow blood sugar in infants and toddlers.
- Decreased energy levels.
- Increased fat around the face and/or abdomen.
Symptoms of Mediastinal Embryonal Carcinoma
Symptoms of mediastinal embryonal carcinoma may include:
- Dyspnea.
- Chest pain.
- Persistent cough.
- Haemoptysiscoughing up blood.
- Superior vena cava syndrome, which has its own set of symptoms:
- Coughing.
- Dyspnea.
- Swelling of the face, neck, and/or upper arms.
Not everyone with the symptoms above will have cancer, but see your general practitioner (GP) if you are concerned.
Diagnosis
If your doctor suspects you have an embryonal carcinoma, they may order the following tests to confirm the diagnosis and refer you to a specialist for treatment:
- Physical examinationan examination of your current symptoms, affected area(s) and overall medical history.
- Endocrine studies.
- Blood teststesting done to measure the levels of certain substances in the blood.
- Imaging tests, potentially including:
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- Ultrasounda type of medical imaging that uses soundwaves to create detailed images of the body .
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- MRI (magnetic resonance imaging)a type of medical imaging that uses radiowaves, a strong magnet and computer technology to create detailed images of the body.
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- CT (computed tomography) scana type of medical imaging that uses x-rays and computer technology to create detailed images of the body.
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- PET (positron emission tomography) scana type of medical imaging that uses radioactive tracers to create detailed images of the body.
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- Chest X-raya type of medical imaging that uses x-ray beams to create detailed images of the body (mediastinal embryonal carcinomas).
- Exploratory surgerya surgical procedure used for conditions that cannot be confirmed by scans and tests alone.
- Biopsyremoval of a section of tissue to analyse for cancer cells (where possible).
Exploratory Surgery
After conducting the previously mentioned diagnostic tests, your doctor may strongly suspect that you have testicular or ovarian cancer. In most cases, a diagnosis can be confirmed after a biopsy, where a section of tissue is removed and analysed for cancer cells. However, doctors avoid conducting a biopsy in patients who have suspected testicular and ovarian cancer as there is a small risk that making an incision in the scrotum or ovary could cause cancer cells to spread. As such, the only way to confirm the diagnosis safely is to remove the affected gonad.
Once the gonad has been removed, it will be sent to a laboratory and analysed for cancer cells.