The short answer
Sudden severe pain in one testicle needs emergency care within hours, because a twisted cord cuts off blood supply. Testicular cancer usually presents as a painless lump or a change in how the testicle feels.
MedlinePlus says surgery for testicular torsion should be done as soon as possible, and that most of the testicle can be saved if it is performed within six hours.
MedlinePlus also says the chance the testicle will need removing rises when blood flow is reduced for more than six hours.
NCI lists a painless lump or swelling, a change in how the testicle feels, a dull ache in the lower abdomen or groin, and sudden fluid build-up in the scrotum as testicular cancer symptoms.
MedlinePlus advises going to an emergency room rather than urgent care for torsion symptoms, in case surgery is needed straight away.
Choose how you want to read this
The whole article, with every detail and caution.
This page is for anyone with testicular pain who wonders if it could be cancer. It explains which pain is an emergency, the common causes, and how testicular cancer usually shows up.
Sudden severe pain is a six-hour question
If the pain came on suddenly and severely in one testicle, stop reading and get to an emergency department.
The concern is testicular torsion. MedlinePlus describes it as twisting of the spermatic cord, which cuts off the blood supply to the testicle and nearby tissue, and can cause permanent damage.
Two lines from MedlinePlus set the clock. Surgery should be done as soon as possible after symptoms begin, and if it is performed within six hours, most of the testicle can be saved. The chance the testicle will need to be removed rises when blood flow is reduced for more than six hours.
That is why nobody watches and waits with this one.
Torsion: what to do in the next hour
MedlinePlus lists these symptoms:
- Sudden severe pain in one testicle, sometimes with no clear reason.
- Swelling on one side of the scrotum.
- Nausea or vomiting.
- The testicle sitting higher than normal.
Go straight to an emergency department. MedlinePlus specifically advises an emergency room rather than urgent care, in case surgery is needed right away.
MedlinePlus says torsion is more common in the first year of life and at the start of puberty, but it can affect males of any age. It may also follow an injury to the scrotum with a lot of swelling, or heavy exercise.
Also get emergency care right away for:
- Pain after an injury with fast swelling.
- Sudden complete inability to pass urine. Call 911 or go to the nearest emergency department.
Infection, injury and the other causes
Slower-onset testicular pain usually has an everyday cause:
- Epididymitis, an infection or inflammation behind the testicle.
- Orchitis, inflammation of the testicle itself.
- A knock or sports injury.
- A varicocele, which is enlarged veins.
- A hydrocele, which is a fluid build-up.
Call your clinician the same day for ache or swelling with a fever, burning when you pee, or discharge. That combination usually means infection, and it responds to treatment.
Testicular cancer is usually painless
This is the part that reframes the question for most readers.
NCI lists these testicular cancer signs:
- A painless lump or swelling in either testicle.
- A change in how the testicle feels.
- A dull ache in the lower abdomen or groin.
- A sudden build-up of fluid in the scrotum.
- Pain or discomfort in a testicle or scrotum.
Pain appears on that list, but it is not the headline. A firm, painless lump on the testicle itself is the classic finding. MedlinePlus notes that testicular cancer is rare and highly treatable, and that it usually occurs between the ages of 15 and 40.
So a lump without pain is not reassuring. It is the reason to book.
Ultrasound, urine test, tumor markers
MedlinePlus describes these tests.
- A physical exam.
- Ultrasound. For suspected torsion, a Doppler scan checks blood flow, and MedlinePlus notes there will be no flow with complete torsion.
- Blood tests for tumor markers, which are substances some tumors release.
- CT scans, if cancer is found.
Checking yourself without panic
MedlinePlus advises examining your testicles monthly and seeking medical attention for lumps, redness, pain or other changes.
Learn what is normal for you. If you find something new, book. Do not check it obsessively for weeks. Testicular Cancer explains what happens after a suspicious scan.
Sources
Common questions
Does testicular pain mean I have cancer?
Usually not. MedlinePlus lists infection (epididymitis, orchitis), injury, varicocele, hydrocele and torsion as testicle problems. Testicular cancer more often causes a painless lump than pain, but any new change should be checked.
How long should I wait?
Do not wait at all for sudden severe pain in one testicle. MedlinePlus says surgery should be done as soon as possible, and that most of the testicle can be saved if it happens within six hours. Ache with fever or burning on peeing needs same-day care.
What should I bring to the visit?
Bring exactly when the pain started and how fast, which side, any injury, any lump you can feel, urinary symptoms, and fever.
Questions to ask your doctor
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Sources last checked: 2026-08-09 what this meansLast updated: 2026-09-29Next planned review: 2027-07-20
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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