Most bumps on the scrotum are benign. The most common causes are cysts, enlarged veins, and minor skin growths, many of which never need treatment. That said, the location, texture, and size of the bump matter, because a small number of scrotal lumps do require medical attention. Here’s how to make sense of what you’re feeling.
Bumps on the Skin vs. Deeper Lumps
The first thing to sort out is whether the bump is on the surface of the scrotal skin or deeper inside the scrotum, near or on the testicle itself. This distinction changes the list of likely causes dramatically.
Surface bumps, the kind you can see and pinch between your fingers, are almost always harmless. Epidermoid cysts (sometimes called sebaceous cysts) are the most common type. They feel like small, firm, round nodules just under the skin and are filled with keratin, a protein your body produces naturally. They can occasionally become inflamed and look red or swollen, which sometimes gets misdiagnosed as an infection. These cysts are benign and only need removal if they bother you.
A less common surface condition is scrotal calcinosis, where calcium deposits form yellowish-white nodules in the scrotal skin. These can range from the size of a grain of rice to a small bean, feel hard, and sometimes cluster together. They’re painless, though occasionally slightly itchy, and are not dangerous.
Genital Warts and Molluscum
Sexually transmitted infections can also cause bumps on scrotal skin. Genital warts from HPV typically appear as small, flesh-colored, rough or cauliflower-textured growths. Molluscum contagiosum produces firm, raised bumps that are white, pink, or skin-colored, often with a small dimple in the center. They range from pinhead to pencil-eraser sized. Both conditions are treatable, and bumps in the genital area should be evaluated to rule out other causes.
Spermatoceles and Epididymal Cysts
If the bump feels like it’s above or behind the testicle rather than on the skin surface, it may be a spermatocele. This is a fluid-filled sac that develops in the epididymis, the small coiled tube sitting on top of each testicle where sperm collect. Spermatoceles are noncancerous, typically painless, and filled with milky or clear fluid that may contain sperm.
Most spermatoceles are small enough that you’d only notice them by chance. If one grows large, you might feel heaviness in that testicle, a sense of fullness behind and above it, or mild discomfort. They generally don’t require treatment unless symptoms become bothersome.
Varicoceles
A varicocele is an enlargement of the veins inside the scrotum, similar to a varicose vein in the leg. About 15% of all adult men have one, and the number rises with age: one study of men over 30 found varicoceles in nearly 35%. They’re more common on the left side due to differences in how blood drains from each testicle, though up to half of affected men have them on both sides.
A varicocele often feels like a soft, irregular mass, sometimes described as a “bag of worms.” It may become more noticeable when you’re standing or straining. Most varicoceles cause no symptoms, but they can contribute to fertility problems. Up to 35% of men with primary infertility and up to 80% of men with secondary infertility have a varicocele.
Hydroceles
A hydrocele occurs when fluid collects in the thin membrane surrounding a testicle. Normally there’s a small amount of fluid in this space, but when excess fluid builds up, the scrotum swells. The swelling is typically painless, smooth, and can sometimes be quite large. Hydroceles are benign and often resolve on their own, though persistent ones can be drained or surgically corrected.
Inguinal Hernias
Sometimes what feels like a scrotal bump is actually tissue pushing down from the abdomen through the inguinal canal. An inguinal hernia creates a bulge near the pubic bone that becomes more obvious when you’re standing, coughing, or straining. In men, large hernias can extend into the scrotum, causing pain and swelling. A key clue is that the bulge often changes size: it may shrink or disappear when you lie down and return when you stand up.
When a Bump Needs Urgent Attention
Two conditions require fast action. Testicular torsion happens when the spermatic cord twists, cutting off blood flow to the testicle. It causes sudden, severe pain and is a surgical emergency. Lifting the testicle typically makes the pain worse. If you experience acute scrotal pain, you should be evaluated within six hours of symptom onset, ideally by ultrasound or surgical exploration.
Epididymitis, an infection of the epididymis, comes on more gradually. Pain builds over hours to days, sometimes with urinary symptoms or fever. Lifting the testicle may partially relieve the pain. This distinction from torsion is not perfectly reliable, though, so sudden or severe pain always warrants prompt evaluation.
How Doctors Evaluate a Scrotal Lump
A physical exam is the starting point. Your doctor will assess whether the lump is on the skin, within the scrotum but separate from the testicle, or attached to the testicle itself. Ultrasound is the primary imaging tool and can reliably distinguish masses outside the testicle from those inside it. A hydrocele, for instance, can sometimes be identified by shining a light through the scrotum (transillumination), since the fluid glows.
If ultrasound reveals a mass inside the testicle itself, that raises concern for testicular cancer, and a urology referral typically follows. Testicular cancer is relatively uncommon but highly treatable when caught early. An intratesticular mass is the key finding that separates it from the many benign causes, which are almost always located outside the testicle.
How to Check Yourself
A self-exam is straightforward. It’s easiest during or after a warm shower, when the scrotal skin is relaxed. Stand in front of a mirror and hold your penis out of the way. Examine each testicle individually by placing your index and middle fingers underneath and your thumbs on top, then gently roll the testicle between them. You’re feeling for hard lumps, smooth rounded bumps, or any change in size, shape, or firmness compared to what’s normal for you.
The epididymis, the soft tube running along the back and top of each testicle, is normal anatomy and can feel bumpy. Getting familiar with its shape helps you distinguish it from something new. Medical organizations don’t universally agree on how often to self-examine, but knowing your own baseline makes it easier to notice a change if one occurs.