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Yolk Sac Tumor of the Testis

Last updated Jan. 9, 2019

Yolk Sac Tumor of the Testis is a type of testicular cancer affecting the germ cells. Germ cells are precursors to sperm cells that will eventually transform into sperms.


What are other Names for this Condition? (Also known as/Synonyms)

  • Testicular Yolk Sac Carcinoma
  • Yolk Sac Tumor of the Testicles
  • YST of the Testis

What is Yolk Sac Tumor of the Testis? (Definition/Background Information)

  • Yolk Sac Tumor of the Testis is a type of testicular cancer affecting the germ cells. Germ cells are precursors to sperm cells that will eventually transform into sperms
  • The testes are the male reproductive organs, equivalent to the ovaries in women. They are housed in the scrotum; the sac-like structure in the groin. The testis have 2 main functions:
    • Male hormone production
    • Sperm production
  • Testicular cancer is cancer of the testicle, or testis. It is the most common form of cancer in young men aged 15-35 years. It is generally aggressive, but treatable when identified early
  • More than 90% of testicular cancers arise from abnormalities in the germ cells. Germ cells are one of the two types of cells in the body. They form sex cells - the sperms and eggs, while the other type, somatic cells, forms everything else (all other body organs and parts)
  • Normal germ cells arise from pluripotent stem cells. Pluripotent stem cells can differentiate into, or become, any cell in the body. Thus, pluripotent stem cells may become either germ cells or somatic cells
  • The process of pluripotent stem cells becoming other cell types is mediated by chemical signaling. Chemicals that act as signals include growth factors, nutrients, and hormones
  • Stem cells that do not respond to normal signals may grow uncontrollably and cause tumors. This tumor-causing potential makes them “neoplastic”. Neoplastic cells that grow aggressively and spread to other areas are cancerous
  • There are two types of testicular germ cell cancer:
    • Seminoma: It is a slow-growing cancer affecting men in their 30s and 40s, which is usually confined to the testis. These are of 2 types - classical and spermatocytic seminoma
    • Nonseminoma: It is a fast-growing cancer affecting males in their late teens through 30s, which aggressively metastasizes, or spreads. These are of 4 types - embryonal carcinoma, yolk sac carcinoma, choriocarcinoma, and teratoma
  • Under the microscope, Yolk Sac Tumor of the Testis resembles the yolk sac of an early developing fertilized egg, or embryo, hence the term “yolk sac”
  • The cause for Yolk Sac Tumor of the Testis is unknown. It is the most common form of testicular cancer in children younger than 3 years of age, especially infants. The condition is rare in adults. It is easily treatable in children, but can be a very severe condition in adults

Who gets Yolk Sac Tumor of the Testis? (Age and Sex Distribution)

Individuals at risk for Yolk Sac Tumor of the Testis include:

  • Children under the age of 3 years
  • Adult men (in rare cases)
  • Caucasians

What are the Risk Factors for Yolk Sac Tumor of the Testis? (Predisposing Factors)

Following are factors that increase one’s susceptibility to Yolk Sac Tumor of the Testis:

  • Family history of testicular cancer
  • Caucasian descent
  • Young age, especially 3 years and younger
  • Undescended testes in youth
  • Decreased immunity, especially due to HIV infection
  • Kidney transplant
  • Presence of carcinoma in situ (CIS), or intra-tubular germ cell neoplasia
  • Hypospadias (male birth defect affecting the urethra)
  • Inguinal hernia
  • Testicular atrophy
  • Gonadal dysgenesis
  • Infertility
  • Smoking
  • Exposure to radiation and industrial chemicals
  • Chemotherapy
  • Viruses (in some rare cases)

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Yolk Sac Tumor of the Testis? (Etiology)

The cause of Yolk Sac Tumor of the Testis is unknown. 

  • It is believed that abnormal differentiation of germ cells gives rise to cancerous cells that lead to the formation of this condition
  • However, how this occurs and the factors that cause it remain under investigation
  • It is likely that this condition has a strong genetic component. Its causes are speculated to be:
  • Over-activation of a gene called the RUNX3 gene
  • Overproduction of a protein called GATA-4 that regulates differentiation of germ cells
  • Descent of the testicles is a necessary factor for proper testicular development. It has been observed that undescended testicles (cryptorchidism) are associated with about 10% of all germ cell tumors such as Yolk Sac Tumor of the Testis. 

What are the Signs and Symptoms of Yolk Sac Tumor of the Testis?

Indications for Yolk Sac Tumor of the Testis include:

  • Blood in vomit and cough
  • Blood in stool, urine
  • Trouble breathing
  • Headache
  • Low blood pressure
  • Anemia
  • Testicular pain, lump in the testes, feeling of heaviness in the scrotum
  • Abdominal pain and swelling
  • Breast pain, especially if accompanied by enlargement
  • Back pain
  • Swelling of the legs
  • Constipation
  • Changes in appetite
  • Fatigue
  • Frequent urination
  • Paralysis

How is Yolk Sac Tumor of the Testis Diagnosed?

Following are techniques that aid in identifying Yolk Sac Tumor of the Testis:

  • Physical examination to detect lumps in the testicles, which do not allow light to pass through
  • Tissue biopsy followed by microscopic analysis and staining
  • Blood tests that include:
  • Complete blood cell count (CBC) blood test
  • Liver function blood test (LFT)
  • Serum tumor marker blood test to detect increases in human chorionic gonadotropin (hCG)
  • Alpha-fetoprotein (AFP) blood test
  • Lactate dehydrogenase (LDH) blood test
  • Testosterone levels blood test
  • Genetic testing to determine mutations associated with Testicular Yolk Sac Tumor
  • Radiological imaging including: 
  • X-ray of the chest, abdomen, and pelvis
  • Ultrasound of the pelvis
  • Computerized tomography (CT) scan of the brain 
  • Vascular radiological studies
  • Whole body bone scan
  • Positron emission tomography (PET) scan

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Yolk Sac Tumor of the Testis?

Following are complications that may arise from Yolk Sac Tumor of the Testis:

  • Infertility
  • Retrograde ejaculation
  • Excessive blood loss
  • Metastasis and the loss of function of the organ/area to which the cancer has spread

How is Yolk Sac Tumor of the Testis Treated?

Treatments for Yolk Sac Tumor of the Testis may include the following procedures:

  • Removal of the original tumor and the metastatic tumors
  • Removal of the testis
  • De-bulking surgery to reduce tumor size, followed by chemotherapy
  • Clotting the vessels in the tumor (embolization)
  • Chemotherapy
  • Radiotherapy 
  • Undertaking treatment of underlying conditions

How can Yolk Sac Tumor of the Testis be Prevented?

Yolk Sac Tumor of the Testis may be avoided through the following measures: 

  • Monthly testicular self-examination
  • Genetic testing in individuals with a family history
  • Limiting exposure to radiation and industrial chemicals 
  • Limiting chemotherapy
  • Not smoking

What is the Prognosis of Yolk Sac Tumor of the Testis? (Outcomes/Resolutions)

  • The following factors determine the prognosis of the condition:
    • Size of the tumor
    • Stage of the tumor
    • Age of the individual
    • Overall health of the individual
    • Location in the testes of the tumor
    • Number of tumor masses present within the testes
  • Generally, the prognosis for Yolk Sac Tumor of the Testis is good in infants, but poor in adults. Also, this tumor often goes unnoticed, until it has spread to other parts of the body, at which point the disease is at an advanced stage

Additional and Relevant Useful Information for Yolk Sac Tumor of the Testis:

  • Testicular cancers are aggressive in nature; they are also very quick to develop. Nonetheless, they are readily treatable
  • It is the most common form of cancer in US men aged 15 to 35 years. However, it is still relatively uncommon, with 5,500 cases in the US each year and 0.2-10.3 cases worldwide per 100,000 persons

What are some Useful Resources for Additional Information?


References and Information Sources used for the Article:


Helpful Peer-Reviewed Medical Articles:


Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Oct. 23, 2015
Last updated: Jan. 9, 2019

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