Testicular cancer is a disease that affects the testicles, the male reproductive glands responsible for producing sperm and male hormones like testosterone. Understanding the different types of testicular cancer, their symptoms, and treatment options is crucial for early detection and effective management.
The testicles play two critical roles in the male body: hormone production (primarily testosterone) and sperm production, essential for fertilization. Sperm cells develop within the seminiferous tubules inside the testicles and mature in the epididymis, a coiled tube located behind each testicle. During ejaculation, sperm travels through the vas deferens to the seminal vesicles, where it mixes with fluids from the vesicles, prostate gland, and other glands to form semen. This semen then exits the body through the urethra, the tube in the penis used for both urination and ejaculation.
Alternative text: Illustration of male reproductive system anatomy showing testicles, epididymis, vas deferens, seminal vesicles, prostate gland, and urethra.
Types of Testicular Cancer
The testicles consist of various cell types, and cancer can originate from any of these. Identifying the specific cell type and cancer type is crucial because treatment strategies and prognosis vary significantly. Doctors analyze cells under a microscope to determine the precise type of testicular cancer.
Germ Cell Tumors (GCTs)
Over 90% of testicular cancers originate in germ cells, the cells responsible for sperm production. Germ cell tumors (GCTs) are broadly classified into two main categories: seminomas and non-seminomas.
Seminomas and non-seminomas occur with roughly equal frequency. However, it’s important to note that many testicular cancers contain a mix of both seminoma and non-seminoma cells. These mixed germ cell tumors are treated as non-seminomas because their growth and spread patterns resemble those of non-seminomas.
Seminomas
Seminomas typically exhibit slower growth and spread compared to non-seminomas. Two primary subtypes of seminomas exist: classical (or typical) seminomas and spermatocytic seminomas.
- Classical Seminoma: Representing over 95% of all seminomas, classical seminomas predominantly affect men between the ages of 25 and 45.
- Spermatocytic Seminoma: This is a rarer form of seminoma usually diagnosed in older men, with an average age of around 65. Spermatocytic tumors tend to grow more slowly and are less likely to metastasize to other parts of the body than classical seminomas.
Some seminomas can elevate blood levels of human chorionic gonadotropin (HCG), a protein that serves as a tumor marker. HCG levels can be measured through a simple blood test and are used for diagnosis and monitoring treatment response.
Non-Seminomas
Non-seminoma germ cell tumors typically affect men in their late teens to early 30s. The four main types of non-seminoma tumors are embryonal carcinoma, yolk sac carcinoma, choriocarcinoma, and teratoma. Many tumors are a mixture of these different types, sometimes including seminoma cells.
Alternative text: Microscopic view of different types of testicular cancer cells, including seminoma, embryonal carcinoma, yolk sac carcinoma, choriocarcinoma, and teratoma.
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Embryonal Carcinoma: These cells are found in about 40% of testicular tumors; however, pure embryonal carcinomas are rare, occurring in only 3% to 4% of cases. Under a microscope, these tumors resemble tissues of very early embryos. This type of non-seminoma tends to grow rapidly and spread beyond the testicle. Embryonal carcinoma can increase blood levels of alpha-fetoprotein (AFP) and human chorionic gonadotropin (HCG).
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Yolk Sac Carcinoma: These tumors are named for their resemblance to the yolk sac of an early human embryo. Other names include yolk sac tumor, endodermal sinus tumor, infantile embryonal carcinoma, or orchidoblastoma. It’s the most common form of testicular cancer in children, especially infants. Pure yolk sac carcinomas are rare in adults. While typically treated successfully in children, they are more concerning in adults, especially if pure. Yolk sac carcinomas respond well to chemotherapy, even if they have spread. This type of tumor almost always increases blood levels of AFP.
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Choriocarcinoma: This is a very rare and fast-growing type of testicular cancer in adults. Pure choriocarcinoma is likely to spread rapidly to other parts of the body, including the lungs, bones, and brain. More often, choriocarcinoma cells are seen with other types of non-seminoma cells in a mixed germ cell tumor. These mixed tumors tend to have a somewhat better outlook than pure choriocarcinomas, although the presence of choriocarcinoma is always a worrisome finding. This type of tumor increases blood levels of HCG.
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Teratoma: Teratomas are germ cell tumors containing areas that resemble each of the three layers of a developing embryo: the endoderm, mesoderm, and ectoderm. Pure teratomas of the testicles are rare and do not increase AFP or HCG levels. Most often, teratomas are seen as parts of mixed germ cell tumors. There are three main types of teratomas:
- Mature teratomas: These tumors are formed by cells that resemble adult tissues. They rarely spread and can usually be cured with surgery, but recurrence is possible.
- Immature teratomas: These are less well-developed cancers with cells that look like those of an early embryo. They are more likely to invade nearby tissues, spread outside the testicle, and recur years after treatment.
- Teratomas with somatic type malignancy: These are very rare cancers with areas resembling mature teratomas but also containing cells that have become a type of cancer that normally develops outside the testicle (such as a sarcoma, adenocarcinoma, or even leukemia).
Carcinoma In Situ (CIS) of the Testicle
Testicular germ cell cancers can originate as carcinoma in situ (CIS), also known as intratubular germ cell neoplasia, a non-invasive form of the disease. In testicular CIS, the cells appear abnormal under a microscope but have not yet spread beyond the walls of the seminiferous tubules. CIS does not always progress to invasive cancer. It’s challenging to detect CIS before it becomes invasive, as it generally doesn’t cause symptoms or form a palpable lump. The only way to diagnose CIS is through a biopsy.
Stromal Tumors
Tumors can also arise from the supportive and hormone-producing tissues (stroma) of the testicles. These are known as gonadal stromal tumors, accounting for less than 5% of adult testicular tumors but up to 20% of childhood testicular tumors. The main types are Leydig cell tumors and Sertoli cell tumors.
Leydig Cell Tumors
These tumors originate in the Leydig cells, which normally produce male sex hormones (androgens like testosterone). Leydig cell tumors can develop in both adults and children. They often produce androgens but may sometimes produce estrogens. Most Leydig cell tumors are benign and seldom spread beyond the testicle, often being cured with surgery. However, a small number can spread to other parts of the body and tend to have a poor outlook, often not responding well to chemotherapy or radiation therapy.
Sertoli Cell Tumors
These tumors originate in Sertoli cells, which support and nourish sperm-making germ cells. Like Leydig cell tumors, Sertoli cell tumors are usually benign. If they spread, they typically do not respond well to chemotherapy or radiation therapy.
Secondary Testicular Cancers
Cancers that originate in another organ and then spread (metastasize) to the testicle are called secondary testicular cancers. These are not true testicular cancers; they are named and treated based on their origin. Lymphoma is the most common secondary testicular cancer and is more common in men older than 50 than primary testicular tumors. The usual treatment is surgical removal, followed by radiation and/or chemotherapy. In boys with acute leukemia, leukemia cells can sometimes form a tumor in the testicle. Along with chemotherapy to treat the leukemia, this might require treatment with radiation or surgery to remove the testicle. Cancers of the prostate, lung, skin (melanoma), kidney, and other organs can also spread to the testicles. The prognosis for these cancers tends to be poor because they have usually spread widely to other organs as well. Treatment depends on the specific type of cancer.
Conclusion
Understanding the different types of testicular cancer is crucial for appropriate diagnosis and treatment. While germ cell tumors are the most common type, other forms such as stromal tumors and secondary cancers can also occur. Early detection, through self-examination and regular check-ups, plays a crucial role in improving outcomes for men diagnosed with testicular cancer. If you notice any unusual changes in your testicles, consult a healthcare professional immediately.
