seminoma
Meaning of seminoma: The slower moving of the two main testicular germ cell tumors, and one of the most curable cancers known.
Definition of seminoma
Seminoma is a cancer that begins in the sperm-forming cells of the testicle. It usually appears as a painless firm swelling on one side, grows more slowly than the other main type of testicular tumor, and is unusually sensitive to both radiation and chemotherapy. Cure is achieved in the large majority of cases, including many that have already spread.
How does it differ from a non-seminoma?
| Seminoma | Non-seminoma | |
|---|---|---|
| Typical age | Thirties and forties | Late teens to thirties |
| Growth | Slower | Faster |
| Alpha-fetoprotein in blood | Never raised by the tumor | Often raised |
| Radiation | Highly sensitive | Much less so |
That third line carries more weight than it looks. A tumor that appears to be a pure seminoma under the microscope but raises alpha-fetoprotein is treated as a non-seminoma, because the marker means non-seminoma cells are present somewhere.
How does it spread?
Spread follows a predictable route rather than a random one. The testicle forms high in the abdomen before descending, and its lymph drainage still runs back along that path, so the first stop is the group of nodes beside the great vessels at the back of the abdomen. From there the chest is next. Reaching the liver, bone or brain through the bloodstream is uncommon and happens late. Knowing the sequence is what makes staging scans so informative in this cancer.
How is it found and treated?
Ultrasound of the testis distinguishes a solid tumor from the many harmless causes of scrotal swelling, and blood is tested for tumor markers. The testicle is removed through an incision in the groin rather than through the scrotum, which avoids seeding tumor into a different lymph territory. What follows depends on stage and ranges from close monitoring alone, through a single dose of chemotherapy, to a full course. Storing sperm beforehand is routinely offered, since treatment can affect fertility.
What raises the risk?
An undescended testicle is the best established factor, and the raised risk persists even after the testicle has been brought down surgically. A previous germ cell tumor in the other testicle, a close family history, and infertility with poor sperm production all add to it. Most people who develop the disease have none of these. Injury, cycling and vasectomy have not been shown to cause it, despite how firmly those beliefs persist.
Also known as
Used in a sentence
Orchiectomy confirmed a pure seminoma confined to the testis.
Good to know
A pure seminoma does not raise alpha-fetoprotein, so a raised level means non-seminoma cells are present and the tumor is managed as a non-seminoma whatever the microscope shows.
Word origin
Where “seminoma” comes from
Built on the Latin semen, meaning seed, with the ending -oma marking a tumor.