Lump on Testicle: Causes, Self-Exam & When to Worry
Most lumps on the testicle are harmless. A soft, movable, pea-sized lump that sits separate from the testicle is almost always a benign epididymal cyst. The one to act on is a hard, painless lump felt on the testicle itself. As a practising andrologist in Chennai, I meet this fear almost every day: a man finds a “lump in my balls” in the shower and is convinced, by the time he reaches me, that it is cancer. I understand the panic. So let me settle it plainly — in roughly 8 out of 10 of the men I examine for a scrotal lump, the cause is completely benign: an epididymal cyst, a varicocele, a hydrocele, or a harmless skin cyst. There is one lump I never brush aside, and I will show you exactly how to recognise it. Book a Consultation Most lumps on the testicle are harmless – this guide shows you how to tell which kind you have. Quick Facts Most testicular lumps are benign — spermatoceles, hydroceles, varicoceles and simple cysts are well-recognised non-cancerous causes of a scrotal lump (Rubenstein, 2004). Position is everything — a scrotal ultrasound reliably tells a lump on the testicle (worrying) from one beside it (almost always benign), and cystic fluid from a solid mass (Akin, 2004). The cancer lump is hard and painless — testicular cancer most often shows up as a painless mass on the testicle itself (Singla, 2025; Chong, 2023). Even cancer is highly curable — testicular cancer is the most common solid malignancy in men aged 15–40 (~10,000 US cases a year, mean age 33), and 90–95% are germ cell tumours with excellent survival (Singla, 2025). Sudden, severe pain is the real emergency — testicular torsion needs surgery within about six hours, when the salvage rate is around 90% (Langan, 2022). Where is the lump? Position decides the diagnosis If you remember one thing from this page, make it this: position, position, position. Where the lump sits on your scrotum tells me, before any scan, what it most likely is. I run through three questions with every man who sits across from me. Is it on the skin, beside the testicle, or on the testicle itself? Pinch the lump gently. If it is in the skin of the scrotum — like a small pellet you can roll under your fingertips — it is usually a harmless sebaceous cyst. If it is a soft, distinct pea sitting above or behind the testicle but clearly separate from it, that is the classic epididymal cyst or spermatocele. The lump that earns a same-week scan is the one that feels part of the testicle itself — a firm nodule you cannot separate from the underlying egg-shaped organ. This is exactly why imaging matters. A scrotal Doppler ultrasound differentiates a testicular mass from an extratesticular one, and tells whether it is cystic, solid or complex — the single test that converts “I don’t know what this is” into a clear answer (Akin, 2004). How many lumps, and one side or both? A soft, worm-like fullness on the left side that you feel more when standing is almost always a varicocele. Generalised swelling of one whole side that lets light shine through points to a hydrocele. A single, hard, fixed nodule on one testicle is the pattern I take seriously. If you also notice a general fullness or heaviness rather than a discrete lump, read my guide on what swelling in the testicles actually indicates. The harmless lumps on the testicle (and most lumps are harmless) Let me reassure you with the actual list. The overwhelming majority of intrascrotal lumps are benign — spermatoceles, hydroceles, varicoceles, epidermoid and simple cysts (Rubenstein, 2004). Here is how each one feels in my hands. Epididymal cyst and spermatocele — the movable pea-sized lump This is the lump I diagnose most. The epididymis is the soft, coiled tube that sits behind and above each testicle, storing and carrying sperm. A small fluid-filled sac there is an epididymal cyst; when it contains sperm it is called a spermatocele. Both feel like a smooth, movable pea, sit separate from the testicle, and are painless. Hydroceles and spermatoceles are common benign adult scrotal swellings (Rioja, 2011). Epididymal cysts most often turn up in men aged 20 to 40 and tend to sit there quietly without causing harm; small, symptomless ones are simply watched, and removal is reserved for cysts large enough to bother you (Zhao, 2023). If it is not growing or hurting, I usually leave it alone. An epididymal cyst – a soft, movable, pea-sized lump that sits separate from the testicle and is harmless. Varicocele — the “bag of worms” A varicocele is a tangle of enlarged veins above the testicle, classically described as feeling like a “bag of worms,” more obvious on the left and when you stand. It is genuinely common — found in roughly 12% of men with normal semen, and far more often (around 40%) in men investigated for infertility (Chiba, 2016). A clinic-based study of men over the age of 40 reported a much higher 48% — but that is a selection-biased figure from men already attending a urology clinic for assessment, not the prevalence in the general male population, so I would not read it as “half of all men” (Besiroglu, 2019). Most cause no trouble at all. The reason I check for them is fertility: varicoceles are the commonest correctable cause of low sperm production, so if you are also trying to conceive, see my explainer on whether varicoceles cause infertility and consider a semen analysis. A varicocele – a soft tangle of enlarged veins above the testicle that feels like a ‘bag of worms’. Hydrocele — a soft fluid swelling A hydrocele is a painless collection of fluid around the testicle. It feels soft and smooth, can grow to a surprising size, and characteristically lets light pass through when a torch is held against it (transillumination). It is benign and