What Is A Germ Cell Tumour?

Overview

Did you know that  germ cells are specialized cells that carry the genetic material for reproduction and give rise to all other cells in the human body? Germ cell tumours, on the other hand, are abnormal growths that endanger the very existence of life. They can be either malignant (cancerous) or benign. Thosel tumours occur when germ cells undergo mutations and proliferate (divide) uncontrollably within the body, producing various types of growths that can affect different organs and tissues.^{1, 2} Although it can be challenging to understand the implications of germ cell tumours, it is vital that we all inform ourselves on the topic as early identification can improve treatment outcomes. Continue reading to discover more about germ cells and germ cell tumours, including the causes, symptoms, diagnosis, treatment, and prevention.

Germ cells are the cells in our bodies that give rise to gametes, whether they are female or male. These cells, during embryo development, go through a series of events of specification, proliferation, and, finally, migration along the midline of the body from the yolk sac, via the hindgut, and towards the genital ridge, where sex determination subsequently takes place. They further differentiate into spermatogonia and oocytes and are called gonocytes. They can also differentiate into adjacent embryonic tissues like the yolk sac or the placenta.^{3, 4} As a result, these cells play a crucial role in ensuring both the genetic variation and survival of our species. Alterations in the formation of these cells can result in problems such as infertility, genetic diseases in the offspring, or even tumours.^{1, 5}

Tumours of these cells can be highly diverse and can develop in people of all ages, from infants to adults. Most germ cell tumours occur before the age of four or after the onset of puberty (more commonly). Nonetheless, it is a form of tumour that accounts for just 3% of tumours in children.^{1, 4} 

Types of germ cell tumours

Within the broad group of germ cell tumours, there is a variety of specific tumour kinds, and this is because of the numerous types of cells that develop from them. There are also several ways different entities classify germ cell tumours. For example, the World Health Organization divides tumours into seminomas (seminomas and dysgerminomas), non-seminomas and germ cell tumours unrelated to germ cell neoplasia in situ.^{6, 7} However, there is also a possibility of dividing the different types of germ cell tumours into alternative three major categories:

• Testicular germ cell tumours:
  • Prepubertal testes germ cell tumours – usually occur in children, such as teratomas
  • Pubertal and adult testes germ cell tumours –  occur after puberty and in adults, can be divided into seminomas and non-seminomas
• Ovarian germ cell tumours:
  • Dysgerminoma – this is the ovarian counterpart of the testicular seminoma
  • Yolk sac tumour
  • Embryonal carcinoma
  • Teratoma – ovarian teratomas can be benign or malignant depending on whether the cells are mature or immature
• Extragonadal germ cell tumours: the mediastinum, pineal gland, retroperitoneum, and sacrococcygeal area are just a few of the places where these tumours can develop outside of the testes or ovaries. They include germinoma, yolk sac tumour, embryonal cancer, choriocarcinoma, and teratoma^{2, 4,8}

Causes of germ cell tumour

It is clear that certain factors contribute to the development of germ cell tumours. However, the precise causes of tumour formation are still not fully understood. There are several factors that may contribute to the development of germ cell tumours, including the formation of the gonadal system, and genetic predisposition. However, more research needs to be done to understand these factors better.^{8, 9}

Signs and symptoms of germ cell tumour

Germ cell tumours can occur in various areas of the body, and the signs and symptoms they produce can vary depending on where they are located. These types of tumours may be benign or malignant, which also influences how they present. The fact that some of the symptoms are not unique to this ailment must be noted to avoid misdiagnosis and ensure proper treatment. A healthcare expert should be seen if you have any lasting or concerning symptoms so that you can  have a precise examination and diagnosis.

Some of the symptoms linked with ovarian germ cell tumours include abdominal pain, palpable pelvic or abdominal pain, and, albeit less common, isosexual precocity (unusally early puberty) or false positive pregnancy test.¹⁰ With testes germ cell tumours, the most common symptoms are a painless lump or swelling, and back pain, while some men have a heavy dragging feeling or overall soreness and, less frequently, severe pain.^{11, 12}

When a germ cell tumour has an extragonadal site, the symptoms will differ depending on that location. The following symptoms may be present if the tumour is in the mediastinum:

• Weight loss
• Swollen supraclavicular nodes (lymph nodes above the collar bone)
• Vena cava superior occlusion syndrome
• Dyspnoea (shortness of breath)
• Coughing

In addition, although less frequent, hoarseness or nausea can also result from this type of tumour.^{13, 14}

Management and treatment for germ cell tumour

There is usually a multidisciplinary team of professionals that manages and treats germ cell tumours, including oncologists, surgeons, radiologists, and pathologists. In terms of treatment, a variety of factors are taken into consideration, including the type r, stage and location of the tumour, and the health of the patient. There are a number of therapeutic options that may be available  including

• Surgery – such as radical orchiectomy (removal of a testicle), is the primary method of removing germ cell tumours, except for tumours in the mediastinum that are not teratomas
• Chemotherapy – generally used in tumours of poor and intermediate prognosis. Chemotherapy  regimens are cisplatin-based and examples include bleomycin, etoposide, and cisplatin (BEP); paclitaxel, ifosfamide and cisplatin (TIP); vinblastine, ifosfamide and cisplatin (VeIP); or etoposide, ifosfamide and cisplatin (VIP)
• Radiotherapy – less common, being employed in cases of metastases to the bone, spinal cord, or central nervous system, as well as non-seminomatous tumours with symptoms.^{13, 15, 16, 17}

Diagnosis

Identifying and diagnosing a germ cell tumour can be a complex process that requires the expertise of a specialised healthcare team. Using an array of diagnostic tests, healthcare professionals can determine the specific type and stage of the tumour with great accuracy.

Healthcare professionals will carefully consider all the symptoms presented by the patient, as well as their medical history and other relevant factors, before making a diagnosis. Additionally, patients should also be aware of these potential overlapping symptoms and communicate them clearly to their healthcare provider to aid  accurate diagnosis and effective treatment. The following diagnostic methods can be used:

• Imaging studies – to pinpoint the location of the tumour
• Biopsies – to confirm the type of tumour
• Blood tests – to help determine the stage and development of the tumour such as:
  • Alpha-fetoprotein (AFP)
  • Human chorionic gonadotrophin (hCG)
  • Lactate dehydrogenase (LDH).^{2, 9, 17, 18}

Having an accurate diagnosis is crucial for healthcare professionals to provide the most effective treatment options for their patients. Appropriate diagnosis and treatment can result in the tumour or cancer being fully cured even in situations where the it has already metastasized. This is why timely diagnosis is a critical factor in the management of cancers. However, treatment alone is not enough, as active follow-up is essential to prevent complications and detect any potential relapses in the coming years. Regular monitoring is key in ensuring patients receive the best possible care and outcomes.^{13, 18, 19}

Risk factors

Although the exact cause of germ cell tumours is still unknown, some things are thought to be risk factors for the growth of these tumours, including:

• Familial history among first-grade relatives (parent, sibiling or offspring)
• Testicular Dysgenesis Syndrome (TDS) – conditions that lead to the abnormal development of male gonads such as:
  • Microlithiasis
  • Hypospadias
  • Cryptorchidism - where one or both testes fail to descend into the scrotum before birth
• Disorders of sexual development:
  • Klinefelter syndrome
  • Mosaic Turner syndrome
• Infertility and hyperfertility
• Previous tumour in the contralateral testicle in men
• HIV infection or AIDS. ^{11, 12, 18, 20}

Additionally, it is important to keep in mind that a tumour won't necessarily form just because a person has risk factors. Similarly, the lack of risk factors does not rule out the development of germ cell tumours. If you have any concerns regarding the risk factors, you should consult your doctor.

FAQs

How can I prevent germ cell tumors?

Some general precautions may help minimise the risk or aid in identifying them early, like control of well-known risk factors, such as family history of the condition. For those at high risk genetic counselling may be recommended. These precautions may not completely guarantee protection and are not specific to germ cell tumours. To accurately diagnose and treat germ cell tumours, a medical exam and consultation are crucial.

How common is germ cell tumour

Germ cell tumours are rare compared to other tumours It is more commonn early children and after the age of 15, but it still accounts for only 3.5% of tumours in children. It is also more prevalent in men.² 

When should I see a doctor

Depending on the location and nature of the tumour, germ cell tumours can present with a variety of symptoms. If you experience any symptoms that are related to these tumours, you should visit a doctor. These circumstances do not necessarily indicate that you have a germ cell tumour, but they do call for a medical evaluation to determine the reason and the best course of action.

Summary

Germ cell tumour is a specific kind of tumour (growth of cells) that develops from the cells that generate sperm or eggs. Although they can grow in other regions of the body, these tumours typically develop in the testicles or ovaries. Germ cell tumours can be cancerous (malignant) orbenignot. If left untreated, malignant germ cell tumours might spread to other bodily regions. These tumours are generally uncommon, but young adults and teenagers are more likely to develop them. Examining the patient's medical history, performing a physical exam, ordering imaging or blood tests, and occasionally performing biopsies are all used to diagnose germ cell tumours. Depending on the type, stage, and location of the tumour, treatment options often include surgery, chemotherapy, and radiation therapy. For germ cell tumours to be successfully managed, early identification and immediate medical care are crucial.