Germinomas are a rare type of tumour that develops from germ-cells. In most cases, germinomas develop in the midline structures of the brain, most commonly in the pineal, suprasellar, basal ganglia and thalamus regions. However, in very rare cases they can develop in the mediastinum, retroperitoneum or sacrococcygeal region.
Germ cell tumours are a rare group of neoplasms that arise from primordial germ cellsa cell that develops into reproductive cells (eggs in females, sperm in males) – 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.
Ovarian dysgerminomas, seminomas, and germinomas share similar histological characteristics and are often considered to be the same tumour, with the name of the tumour varying according to anatomical location. When arising in the ovary, the tumour is termed a dysgerminoma; in the testis, it is called a seminoma; and when occurring at extragonadal sites – most commonly within the central nervous system – it is referred to as a germinoma.
Germinomas are slightly more common in males, and tend to be diagnosed in children between the ages of 10-12. However, anyone can develop this disease.
Treatment
When cancers are detected, they are staged and graded based on size, metastasis, and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you. However, because of how rare germinomas are, there is currently no standard staging and grading system for this disease. Instead of staging and grading, your doctor will recommend a treatment plan based on the following factors:
- Cancer location.
- Whether or not the cancer has metastasised.
- Your age.
- General health.
- Your treatment preferences.
Your doctor may also 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 for germinomas may include:
- 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.
- Surgery – generally limited to biopsyremoval of a section of tissue to analyse for cancer cells and treatment of obstructive hydrocephalusa build up of cerebrospinal fluid (CSF) in the brain, causing pressure and potentially damaging brain tissue.
- 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.
Risk factors
Because of how rare germinomas are, there has been limited research done into the risk factors of this disease.
Symptoms
Symptoms of germinomas vary based on location.
General Symptoms
General symptoms of germinomas include:
- General weakness.
- Irritability.
- Headache.
- Nausea and/or vomiting.
- Changes in mental status.
- Seizures.
- Endocrine abnormalities.
- Delayed puberty.
Symptoms of Germinomas in the Pinel Gland Region
- Hydrocephalus, 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.
- Parinaud’s syndrome
Symptoms of Germinomas in Suprasellar and Pituitary Gland Regions
- 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 Germinomas in the Basal Ganglia and Thalamus Regions
- Cognitive abnormalities.
- Changes to mental status.
- Hemiparesis (muscle weakness on one side of the body).
- Dystonia.
- Rigidity.
- Bradykinesia (decreased movement and/or speed).
- Dyskinesia (uncontrolled, involuntary movements).
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 a germinoma, 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.
- Neurological examinationan assessment of sensory and motor functions, such as vision, balance and coordination.
- Blood teststesting done to measure the levels of certain substances in the blood.
- Endocrine studies.
- Imaging tests, potentially including:
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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.
- Lumbar puncturea procedure that involves inserting a needle between two vertebrae in the lower spine and extracting a sample of cerebrospinal fluid (CSF) for analysis.