Mass in the Scrotum: What Your Lump Could Be

Inside or outside the testicle: the first question

The scrotum contains each testicle, the coiled epididymis behind it that stores sperm, the spermatic cord (blood vessels and the vas deferens), and a thin lining around the testicle. Doctors sort scrotal masses by where they come from, because this predicts risk:

• Masses outside the testicle (extratesticular) are almost always benign: cysts, fluid, veins, hernias and infection.
• Masses within the testicle (intratesticular) are cancer until proven otherwise, though some turn out to be benign.

You can often feel the difference. A lump you can separate from the smooth, egg-shaped testicle, sitting above or behind it, is usually extratesticular. A hard area that is part of the testicle itself needs prompt imaging.

Common causes of a scrotal mass

Spermatocele and epididymal cysts

A spermatocele is a fluid-filled sac in the epididymis containing sperm. Epididymal cysts are similar but contain clear fluid. Both feel like a smooth, separate ball at the top of the testicle. They are very common after age 40, often both sides, and harmless. They only need removing if they grow large or uncomfortable.

Hydrocele

A hydrocele is fluid collecting in the sac around the testicle, making the scrotum swell evenly. It is common in newborns, where it usually resolves by age 1 to 2. In adults it can follow injury, infection or surgery, and occasionally a tumor, so a new adult hydrocele gets an ultrasound to check the testicle inside.

Varicocele

A varicocele is a cluster of enlarged veins in the spermatic cord, like varicose veins. It affects about 15 in 100 men, nearly always on the left, and usually appears in the teens. Most cause no trouble. Some cause a dull ache, a smaller testicle on that side, or reduced fertility. A varicocele that appears suddenly in an older man, or on the right side only, needs imaging of the abdomen to rule out a kidney mass pressing on the vein.

Inguinal hernia

An inguinal hernia is a loop of bowel or fat pushing through a weak spot in the groin and sometimes down into the scrotum. It gets bigger when you stand, cough or strain and often goes back when lying down. A hernia that becomes stuck, painful and tender is an emergency.

Infection and inflammation

Epididymitis causes pain and swelling behind the testicle that builds over a day or two. In men under 35 it is usually caused by sexually transmitted chlamydia or gonorrhea. In older men it is more often linked to urinary infections or prostate problems. Orchitis, inflammation of the testicle itself, can come with it or follow mumps.

Hematocele and injury

A hematocele is blood collecting around the testicle, usually after a blow to the scrotum. Significant trauma needs an ultrasound to check for a ruptured testicle, which needs surgery.

Serious causes

Testicular cancer

Testicular cancer is the most common cancer in men aged 15 to 40, though it is still uncommon overall. Signs include:

• a painless lump or hard area on the testicle, often found in the shower
• swelling or enlargement of one testicle
• a dragging, heavy feeling in the scrotum, or a dull ache in the lower belly or groin
• less commonly, breast tenderness or growth, or back pain from spread to lymph nodes

Risk is higher with an undescended testicle (even if corrected), a previous testicular cancer, or a father or brother who had it. Testicular cancer is one of the most curable cancers, with cure rates above 95 in 100 when found early.

Testicular torsion

Torsion is twisting of the spermatic cord, cutting off the testicle's blood supply. It causes sudden severe pain and swelling, most often in teenagers. The testicle may sit higher and lie sideways. It needs surgery within about 6 hours to save the testicle. Do not wait to see if it settles.

How doctors evaluate a scrotal mass

A doctor will ask when you noticed it, whether it has changed, whether it hurts, and about injury, fever, urinary symptoms and sexual history. They will examine you lying and standing:

• feeling each testicle, the epididymis and the cord
• shining a light through the scrotum (transillumination): fluid lumps glow, solid ones do not
• asking you to cough or strain to check for a hernia or varicocele

Tests include:

• Scrotal ultrasound: the key test. It shows whether a mass is inside the testicle, solid or fluid-filled, and checks blood flow for torsion.
• Urine tests and STI swabs for suspected infection.
• Tumor marker blood tests (AFP, beta-hCG and LDH) if cancer is suspected.
• CT scan for staging if cancer is found.

Doctors do not take a needle biopsy of a suspected testicular cancer, because it can spread cancer cells. Instead, the whole testicle is removed through the groin (radical inguinal orchiectomy) and examined.

Treatment by cause

• Small cysts, spermatoceles and hydroceles: no treatment unless large or uncomfortable. Surgery is simple if needed.
• Varicocele: supportive underwear and pain relief, or surgery or embolization for pain, a shrinking testicle or fertility problems.
• Hernia: usually planned surgical repair.
• Epididymitis: antibiotics (and treatment of partners if an STI is the cause), rest, scrotal support, ice and anti-inflammatory pain relief.
• Torsion: emergency surgery to untwist and fix the testicle.
• Cancer: orchiectomy, then surveillance, chemotherapy or radiation depending on type and stage.

Testicular self-examination

Checking once a month after a warm shower helps you notice changes early:

1. Hold the scrotum in your palm and examine each testicle in turn.
2. Roll each one gently between thumb and fingers. It should feel smooth, firm and egg-shaped.
3. Feel the soft, tube-like epididymis at the back. This is normal and not a lump.
4. Note any hard area, lump, change in size, or heaviness, and see a doctor.

It is normal for one testicle to be slightly larger or hang lower than the other.

Frequently asked questions

Is a lump in the scrotum serious?

Most scrotal lumps are benign, such as cysts, hydroceles and varicoceles. A firm lump that is part of the testicle can be testicular cancer and needs prompt checking. Sudden severe pain is an emergency. Because you cannot reliably tell them apart yourself, see a doctor about any new lump.

What does a cancerous lump on the testicle feel like?

It is usually hard, irregular or pea-sized, part of the testicle itself rather than separate from it, and often painless. Some men notice the whole testicle becoming larger or heavier instead of a distinct lump.

Can a scrotal mass go away on its own?

Some can. Hydroceles in babies, swelling from epididymitis after treatment, and bruising from injury usually settle. Cysts and varicoceles tend to stay but rarely cause harm. A solid lump in the testicle does not go away and needs evaluation.

What is the lump at the top of my testicle?

A soft, smooth lump at the top or back of the testicle is most often an epididymal cyst or spermatocele. These are harmless. The epididymis itself also sits there and is often mistaken for a lump. An ultrasound can confirm it.

Which doctor should I see for a scrotal mass?

Start with your primary care doctor, who will examine you and arrange an ultrasound. You will be referred to a urologist if the lump is in the testicle, needs surgery, or the diagnosis is unclear.