Most bumps found on or around the testicles turn out to be harmless. Roughly three out of four masses that sit outside the testicle itself are benign, and even many lumps on the scrotal skin are nothing more than clogged glands or fluid-filled cysts. That said, location matters enormously: masses inside the testicle carry a much higher chance of being cancerous. The challenge is that you often cannot tell the difference by touch alone, which is why understanding the common causes and knowing when to see a doctor can save you a lot of unnecessary worry or, in rarer cases, catch something serious early.
Bumps on the Scrotal Skin
The most common scrotal bumps are the ones you can see and feel right on the surface of the skin. These are almost never dangerous, but they can be confusing if you have never noticed them before.
Epidermal inclusion cysts (sometimes called sebaceous cysts) are firm, round, pea-sized nodules that sit just under the scrotal skin. They form when skin cells get trapped beneath the surface and begin to accumulate keratin and other debris. They are benign and usually painless unless they become infected or rupture, at which point they can swell, redden, and hurt.1PubMed Central. Multiple Swellings Over the Scrotum: Epidermal Inclusion Cysts Occasionally one grows large enough to be mistaken for something more worrisome. In one reported case, a scrotal epidermoid cyst was initially confused with a testicular malignancy on clinical examination; surgical removal and lab analysis confirmed it was completely benign.2Journal of Spleen and Liver Research. Scrotal Epidermoid Cyst Presenting as Extra-Testicular Scrotal Mass: A Diagnostic Dilemma Complete surgical excision is the standard treatment when one becomes bothersome, and outcomes are typically excellent.3PubMed Central. Giant Scrotal Epidermoid Cyst Containing 600 g of Keratinous Material: A Rare Testis-Preserving Surgical Excision
Fordyce spots are another frequent finding. These are tiny, pale or yellowish dots clustered on the scrotal skin. They are simply visible sebaceous (oil) glands and are entirely normal. Nearly everyone has them to some degree. Ingrown hairs, folliculitis (infected hair follicles), and small skin tags can also produce bumps on scrotal skin that look alarming but are medically trivial. If a skin-level bump is painless, moves freely with the skin when you roll it between your fingers, and is not growing rapidly, it is very likely one of these harmless conditions.
Fluid-Filled Lumps Near the Testicle
Bumps that feel smooth, round, and somewhat squishy are often fluid-filled. Two of the most common are spermatoceles and hydroceles.
A spermatocele is a cyst that forms in the epididymis, the coiled tube that sits behind and above each testicle. It contains fluid that may include dead sperm cells. Spermatoceles are almost always painless, and most are discovered incidentally during an ultrasound or a physical exam. They tend to feel like a small, separate lump sitting on top of the testicle rather than part of it. Most need no treatment unless they grow large enough to cause discomfort.
A hydrocele is a buildup of fluid inside the thin sac that surrounds the testicle. It can make one side of the scrotum look swollen or feel heavier than usual. Hydroceles can develop after injury, infection, or inflammation, though many arise without any clear trigger.4PubMed Central. Classifying Hydroceles of the Pelvis and Groin: An Overview of Etiology, Secondary Complications, Evaluation, and Management A classic feature is that a hydrocele transilluminates: if you hold a flashlight behind the swelling in a dark room, the light passes through because the mass is fluid rather than solid tissue. Hydroceles are benign, but large ones can cause discomfort or self-consciousness, and they sometimes mask other conditions underneath, so an ultrasound is still a good idea if you develop one.
Varicoceles
A varicocele does not feel like a discrete bump so much as a soft, irregular mass that some people describe as feeling like a “bag of worms.” It is caused by enlarged veins within the network of blood vessels that drain the testicle. Varicoceles are extremely common, affecting a substantial share of adult men, and they appear on the left side far more often than the right because of how the veins on each side connect to different blood vessels higher up.
Many varicoceles are completely painless and discovered by accident. Others cause a dull ache or heaviness in the scrotum, especially after prolonged standing or exercise. In some cases they lead to testicular shrinkage or changes in sperm quality.5PubMed Central. Varicoceles: Overview of Treatment from a Radiologic and Surgical Perspective The veins themselves become dilated and tortuous, forming the distinctive lumpy feel.6PubMed. Anatomy of the spermatic venous plexus (pampiniform plexus) in men with and without varicocele: intraoperative venographic study Treatment, whether surgical or through a minimally invasive radiologic procedure, is typically reserved for people who have pain or fertility concerns. If you notice a varicocele-like mass for the first time on the right side only, or one that does not shrink when you lie down, it is worth getting evaluated promptly, because in rare cases a new right-sided varicocele can signal something obstructing the vein from above, such as a kidney mass.
Infections and Inflammation
A bump that comes on suddenly, hurts, and is accompanied by warmth, redness, or swelling of the scrotum points toward an infectious or inflammatory cause. The two main culprits are epididymitis (inflammation of the epididymis) and orchitis (inflammation of the testicle itself). They sometimes occur together.7Frontiers in Urology. Epididymitis, orchitis, and epididymo-orchitis associated with SARS-CoV-2 infection in pediatric patients: A systematic review
In younger, sexually active adults, epididymitis is most often caused by sexually transmitted bacteria like chlamydia or gonorrhea. In older men, it more commonly stems from urinary tract bacteria. Orchitis can follow a systemic viral infection, with mumps being the classic example, though it is less common in vaccinated populations. Symptoms usually include progressive pain over a day or two, a swollen and tender epididymis or testicle, and sometimes fever or urinary symptoms. Antibiotics clear most bacterial cases, and anti-inflammatory medication helps with pain. The swelling itself can feel like a new lump, which is why many people first notice it and worry about cancer. The key difference is that infectious swelling is almost always painful and develops relatively fast, whereas a cancerous mass tends to be painless and grows slowly.
Post-Procedural and Trauma-Related Bumps
If you have had a vasectomy or any scrotal surgery, a new bump may be related to the procedure. Sperm granulomas are small, firm nodules that form when sperm leak from the cut end of the vas deferens and provoke a localized inflammatory reaction. They are one of the recognized long-term complications of vasectomy, alongside occasional hematomas and chronic discomfort at the surgical site.8PubMed Central. Review of Vasectomy Complications and Safety Concerns Granulomas are benign and usually small, but they can be tender. Most resolve on their own or with anti-inflammatory medication; persistent, painful ones can be surgically removed.
Trauma to the scrotum, whether from a sports injury or an accident, can cause hematoceles (collections of blood inside the scrotal sac) or localized swelling that mimics a mass. These typically come with a clear history of injury, bruising, and pain. Even if the cause seems obvious, significant scrotal trauma warrants an ultrasound to rule out a testicular rupture, which needs surgical repair.
When a Bump Could Be Cancer
Testicular cancer is the scenario everyone fears, and it is worth taking seriously even though it is relatively uncommon overall. It typically strikes younger adults between the ages of 15 and 35, making it the most common solid tumor in that age group. The classic presentation is a painless, hard lump on or within the testicle itself. That distinction matters: about nine out of ten masses located inside the testicle are malignant, which is essentially the inverse of what is seen with masses that sit outside the testicle.9PubMed Central. Extratesticular masses focusing on MRI findings
A painless, firm mass that feels attached to the testicle and does not transilluminate is the red-flag combination. Other warning signs include a testicle that feels noticeably heavier than the other, a dull ache in the lower abdomen or groin, or swelling that does not go away. Testicular cancer is highly treatable when caught early, with cure rates above 95 percent for localized disease, so the cost of a false alarm (one unnecessary ultrasound) is trivially small compared to the cost of delay.
Risk factors include a history of an undescended testicle, a family history of testicular cancer, and a prior cancer in the other testicle.10PubMed Central. Risk Factors for Testicular Cancer: Environment, Genes and Infections-Is It All? Having one or more risk factors does not mean you will develop cancer, but it does mean you should pay closer attention to changes.
Rare Paratesticular Tumors
Not every tumor in the scrotum is testicular cancer. There is a separate, less well-known category of tumors that arise in the structures around the testicle rather than inside it. These paratesticular tumors are rare and usually benign, but they add to the list of things a bump could be.
The most common benign paratesticular tumor is the adenomatoid tumor, which typically grows on the epididymis. It tends to appear in people around age 36 on average and is slow-growing and painless.11PubMed Central. Epididymal Adenomatoid Tumor: A Very Rare Paratesticular Tumor of Childhood Lipomas of the spermatic cord are another common benign finding. On the malignant side, sarcomas can develop in the scrotal soft tissues, and while rare, they are something doctors have to consider when evaluating a solid mass outside the testicle, especially in adults.12PubMed. Multimodality imaging of paratesticular neoplasms and their rare mimics The old teaching that “if it’s outside the testicle, it’s benign” is a useful rule of thumb but not an absolute one; malignancies can and do occur in the extratesticular space, even if they are far less common there.13PubMed. Gamut of Extratesticular Scrotal Masses: Anatomic Approach to Sonographic Differential Diagnosis
Testicular Torsion Is Not a Bump, but It Can Feel Like One
Testicular torsion deserves mention because it sometimes presents with scrotal swelling that a panicked person might interpret as a new lump. In torsion, the spermatic cord twists on itself, cutting off blood flow to the testicle. The hallmark is sudden, severe pain, often accompanied by nausea and swelling. It is most common in adolescents and young adults, partly because hormonal changes and growth can make the testicular attachments less stable.14Grand Journal of Urology. Testicular Torsion and Contralateral Torsion of the Appendix Testis
This is a true emergency. The testicle needs its blood supply restored within about four to six hours for the best chance of survival. If you or someone you know develops sudden, severe testicular pain with swelling, go to an emergency room immediately. Do not wait to see if it gets better. The related but less urgent condition, torsion of a testicular appendage (a tiny vestigial structure attached to the testicle), can cause similar but usually milder pain, sometimes with a visible “blue dot” sign on the skin. It is painful but not an emergency, as the appendage itself is nonfunctional.
How Doctors Figure Out What a Bump Is
A physical exam can narrow the possibilities, but ultrasound is the workhorse of scrotal diagnosis. High-resolution ultrasound combined with color Doppler imaging gives a detailed picture of the anatomy and blood flow within the scrotum, helping clinicians distinguish a fluid-filled cyst from a solid mass, and a well-vascularized tumor from a benign structure with normal blood flow.15Advanced International Journal for Research. Evaluation Of Scrotal Lesions Using High-Resolution Ultrasonography And Color Doppler: A Cross-Sectional Study In one study, color Doppler ultrasound detected testicular cancer with a sensitivity of about 89% and a specificity of about 78%, making it a strong first-line tool.16PubMed Central. Color doppler ultrasound for diagnosis of testicular carcinoma: A comparison with gold standard histopathology
If a solid intratesticular mass is found on imaging and cancer is suspected, blood tests for tumor markers come next. Three markers in particular help with diagnosis and staging: human chorionic gonadotropin (hCG), alpha-fetoprotein (AFP), and lactate dehydrogenase (LDH).17PubMed Central. Role of biochemical markers in testicular cancer: diagnosis, staging, and surveillance Elevated levels of these markers can point toward certain types of testicular cancer even before surgery, and tracking their levels after treatment helps monitor for recurrence.18PubMed. Value of five tumor markers (AFP, CEA, hCG, hPL and SP1) in diagnosis and staging of testicular germ cell tumors Normal marker levels do not rule cancer out entirely, but they are an important piece of the diagnostic puzzle.
MRI is sometimes used as a follow-up when ultrasound findings are ambiguous, particularly for extratesticular masses where the distinction between benign and malignant can be tricky.9PubMed Central. Extratesticular masses focusing on MRI findings The definitive diagnosis for any suspected malignancy, however, comes from tissue analysis after surgical removal.
Self-Examination and What to Feel For
Regular self-examination is the simplest way to catch changes early. The best time to check is after a warm shower, when the scrotal skin is relaxed. Roll each testicle gently between your thumb and fingers. A healthy testicle feels smooth, oval, and slightly firm, like a hard-boiled egg. The epididymis sits along the back, and it is normal for it to feel slightly bumpy or rope-like. What you are looking for is anything new: a hard lump on the testicle surface, a noticeable change in size or weight, or a mass that was not there before.
Testicular cancer commonly shows up as a painless scrotal mass, which is exactly the kind of thing a self-exam can detect.19PubMed. Testicular self-examination for early detection of testicular cancer Major urology guidelines recommend self-examination for people who have already had testicular cancer or are at elevated risk. Its role in the general population is more debated, partly because testicular cancer is uncommon and has excellent survival rates even when caught at a later stage. Still, familiarity with your own anatomy is the foundation: if you know what normal feels like, you are much more likely to notice when something changes.
Why People Wait Too Long to Get Checked
One of the biggest practical barriers to getting a scrotal lump evaluated is embarrassment. Research on diagnostic delay in testicular cancer found a strong link between embarrassment and how long patients waited before seeing a doctor.20PubMed Central. Delay in Diagnosis of Testicular Cancer; A Need for Awareness Programs Some people put off an appointment for weeks or months because they feel uncomfortable bringing up a genital concern, or because they assume the bump will go away on its own.
This is understandable but counterproductive. Doctors examine scrotal lumps routinely, and the exam itself is quick and straightforward. If the physical exam is inconclusive, an ultrasound is painless, noninvasive, and takes about fifteen minutes. The vast majority of people who go in worried about a bump leave with a reassuring answer: a cyst, a hydrocele, a varicocele, or some other benign finding. For the small percentage whose bump turns out to be something more serious, early evaluation is the single most important factor in a good outcome. The calculus is simple: a brief moment of awkwardness is a low price for either peace of mind or an early diagnosis.
When You Cannot Tell Where the Bump Is
A frustrating reality of scrotal self-exams is that the anatomy is compact, and it is not always easy to tell whether a bump is in the skin, attached to the epididymis, or part of the testicle. A small cyst sitting right on top of the testicle can feel like it is inside it, and a soft varicocele can feel like generalized scrotal fullness rather than a discrete mass. If you are unsure, that is not a failure of your exam technique. Scrotal anatomy genuinely is confusing to palpate, and the inability to localize a bump precisely is itself a good reason to get an ultrasound. Ultrasound can pinpoint whether a mass is intratesticular or extratesticular with high accuracy, which immediately changes the clinical picture. As noted earlier, the location of the mass is one of the strongest predictors of whether it is likely to be benign or malignant, so getting that answer is worth the visit even if you suspect the bump is harmless.