There are two main types of testicular cancer: germ cell tumors and stromal tumors.
Germ cell tumors account for about 95% of all testicular cancer cases. Stromal tumors are less common among adults but more commonly found in children.
Testicular cancer has the greatest chance of recurring within the first two years after treatment. Beyond this point, recurrence is very rare.
Testicular cancer is the most common type of cancer among young men. While guys of any age can be affected, the vast majority are diagnosed in their 20s and 30s. The good news? Testicular cancer is also one of the most treatable types of cancer. It has the highest known survival of any solid cancer, with long-term cure rates around 95%.
The best thing you can do to protect yourself is know your nuts. But it’s also smart to know about the different types of testicular cancer – because, yes, there’s more than one, and treatment can vary depending on what kind you’re dealing with.
In this article, we’ll cover two main categories of testicular cancer: germ cell tumors and stromal tumors. We’ll also dig into some of the different versions of each.
This is by far the most common type. Around 95% of all testicular cancers start in the germ cells – that is, cells that make sperm.
There are two kinds of germ cell tumors: seminomas and non-seminomas. We’ll also look at a precancerous condition that can (but does not always) lead to germ cell tumors, called intratubular germ cell neoplasia (ITGCN).
It’s possible for germ cell tumors to have both seminoma and non-seminoma cells. Treatment widely varies depending on the type of cancer.
Seminoma literally means ‘semen tumor’. Seminomas account for a little more than half of all testicular cancers. They tend to spread slowly and are usually treated with surgery, chemotherapy or radiation.
There are two categories of seminomas:
Classical seminomas: most commonly found in men in their 30s, 40s and 50s. These account for almost all seminoma tumors.
Spermatocytic seminoma: much rarer and usually found among older men.
Non-seminomas, also referred to as non-seminomatous germ cell tumors (NSGCT) account for slightly less than half of all testicular cancers and are more commonly found in younger adult men. They tend to grow more quickly than seminoma tumors.
Non-seminoma cancers can contain any of the following five types of cells – and in many cases, more than one. They’re often referred to as ‘carcinomas’, which is a term for any cancer that starts in the skin or the tissues lining internal organs.
Embryonal carcinoma: this can be a more aggressive type of cancer cell found in a little less than half of all non-seminoma tumors. However, it’s rarely found on its own. (More on why that’s a good thing below.)
Yolk sac carcinoma: these are more commonly found in young children with testicular cancer but can often show up in older patients.
Choriocarcinoma: this is a very rare and aggressive form of cancer, especially when it’s found on its own. However, like embryonal carcinoma, it’s usually found with other types of cancer cells.
Teratoma: the name for this cell comes from the Greek word for ‘monster’, which fortunately has more to do with its appearance than anything else. Under a microscope, this kind of tumor looks a bit, well like a human embryo. Pure teratomas are extremely rare. They’re generally treated with surgery, as they don’t respond to radiation or chemotherapy.
Seminoma: it can often be a component of non-seminoma tumors (NSGCT); if only seminoma is present, then it is categorized as seminoma, not NSGCT.
One important thing to remember: most non-seminoma tumors contain a mix of different types of cancer cells, which is a good thing. Generally speaking, tumors with a mix of cells are easier to treat than the so-called ‘pure’ versions consisting of only one type of cell.
Technically not a cancer, ITGCN is sometimes referred to as the ‘progenitor of germ cell tumors or a stage 0 illness. In other words, it’s a precancerous condition that can lead to testicular cancer, but doesn’t always. These abnormal cells develop into cancer in about 50% of men who have them.
ITGCN (formerly known as carcinoma in situ, or CIS) can be difficult to detect. When it is caught, it’s usually while testing for something else, such as infertility. Some doctors recommend surgery or radiation to remove the cells before they have a chance to develop into cancer. Others suggest monitoring for any changes before treatment, a practice known as watchful waiting.
Stromal tumors are pretty rare among adults, around 5% of all cases. But they’re more common in kids, accounting for 1 in 5 childhood cases of testicular cancer.
Sometimes referred to as gonadal stromal tumors, they’re often benign. They’re also less likely to spread to other parts of the body, and usually respond well to treatment. In a small number of cases, stromal tumor cells can spread beyond the testicles, making them harder to treat.
There are two main types of stromal tumors:
Leydig cell tumors: these affect the cells that make male hormones like testosterone
Sertoli cell tumors: these affect cells that support the germ cells in making sperm
If testicular cancer relapses, it’s usually within two years of finishing treatment — and it can usually be cured. On very rare occasions, testicular cancer can recur more than two years after treatment — even decades after. This is referred to as ‘late relapse’.
There are three possible types of recurrence:
Local: cancer that comes back in the same place as before (extraordinarily rare when the entire testicle has been removed)
Regional: cancer that comes back in a nearby part of the body, typically lymph nodes in the back of the abdomen
Distant: cancer that returns in a different place — most commonly the lungs, but it also can recur in neck lymph nodes, liver or brain
Some cancers can start in another part of the body and spread to the testicle. These are referred to as secondary testicular cancers. For example:
Lymphoma is the most common secondary testicular cancer. It’s actually more common in men over 50 than primary testicular cancer. It’s usually treated with surgery, followed by chemotherapy and/or radiation.
Leukemia cells can sometimes form into testicular tumors in children.
Whatever kind of testicular cancer you or your loved one has, it’s important to talk to your medical care team about what to expect during and after treatment.