Testicular Lump or Pain — When to Get a Scan
If you have recently discovered a lump in your testicle, or are experiencing unexplained scrotal pain, it is entirely natural to feel anxious. For many men, the immediate thought jumps to the worst-case scenario. The reality, however, is that the vast majority of testicular lumps and scrotal symptoms are caused by benign (non-cancerous) conditions — epididymal cysts, fluid accumulation, or enlarged veins are far more common than malignancy.
That said, any new lump, swelling, or unexplained pain in the testicles requires prompt professional evaluation. Early, accurate diagnosis is the key to peace of mind and, where necessary, effective treatment. This article explains what these symptoms might mean, when you need to seek emergency care, and how a private scrotal ultrasound scan can provide the definitive answers you need.
⚠ Red Flags: When to Go to A&E Immediately
While most testicular symptoms can be evaluated during a scheduled appointment, certain signs indicate a medical emergency. If you experience sudden, severe testicular pain, go to your nearest Accident and Emergency (A&E) department immediately — do not wait.
Sudden and severe pain is the hallmark symptom of testicular torsion, a condition where the spermatic cord twists and cuts off the blood supply to the testicle. Without urgent surgical intervention, the testicle can suffer irreversible damage within hours. The window for saving the testicle is typically four to six hours from the onset of pain.
Go to A&E without delay if you experience:
- Sudden, severe pain in one testicle
- Nausea or vomiting accompanying the pain
- A testicle that appears to sit higher than normal or at an unusual angle
- Sudden scrotal swelling with severe pain in a child or adolescent
Do not book a routine scan for sudden, severe pain. Go directly to A&E.
Understanding Testicular Lumps and Pain
When evaluating testicular symptoms, clinicians generally categorise presentations based on whether they involve a lump, pain, or a combination of both. Understanding these patterns helps clarify the likely cause and the appropriate urgency of assessment.
The Painless Lump
A painless lump is the most common presentation that prompts men to seek a scan. While it is essential to have any painless lump assessed urgently to rule out testicular cancer, the majority are benign. The key clinical distinction is whether the lump arises from the testicle itself (intratesticular) or from the surrounding structures (extratesticular).
Epididymal Cyst: A fluid-filled sac within the epididymis — the coiled tube at the back of the testicle that stores and transports sperm. Epididymal cysts are extremely common, particularly in men over 40, and are almost always benign. They typically feel smooth, soft, and separate from the testicle itself.
Spermatocele: Similar to an epididymal cyst but containing fluid with sperm cells. Also benign and very common. On ultrasound, these appear as small, well-defined cystic structures adjacent to the testicle.
Hydrocele: A build-up of fluid within the sheath surrounding the testicle, causing diffuse scrotal swelling rather than a discrete lump. Hydroceles can be primary (idiopathic) or secondary to infection, injury, or occasionally tumour. Ultrasound is essential to exclude an underlying cause.
Varicocele: Enlarged, dilated veins within the scrotum — analogous to varicose veins in the leg. Varicoceles are present in approximately 15% of the male population and in up to 40% of men investigated for infertility [1]. They most commonly affect the left side due to the angle at which the left testicular vein drains into the renal vein. They may cause a dull ache or feeling of heaviness, particularly after prolonged standing, but are often painless.
Testicular Cancer: Although far less common than the benign conditions above, a painless, hard lump arising from the testicle itself is the classic presentation of testicular cancer. Testicular cancer is the most common cancer in men aged 15 to 49 in the UK, with approximately 2,400 new cases diagnosed each year [2]. Current clinical guidelines advise that any new, unexplained testicular lump should be evaluated with an ultrasound scan as a matter of urgency — typically within two weeks under the NHS two-week-wait pathway, or sooner via private access.
The Painful Lump or Swelling
When a lump or swelling is accompanied by pain and tenderness, it more often points to an inflammatory or infectious process.
Epididymitis and Epididymo-orchitis: Inflammation of the epididymis (epididymitis), which may spread to the testicle itself (epididymo-orchitis). This is frequently caused by bacterial infection, including sexually transmitted infections such as chlamydia or gonorrhoea in younger men, and urinary tract infections in older men. The presentation is typically a gradual onset of pain, scrotal swelling, warmth, and tenderness — developing over days rather than hours. Systemic symptoms such as fever and urinary discomfort may also be present.
Scrotal Pain Without a Distinct Lump
Dull, Persistent Ache: A chronic dull ache or feeling of heaviness in the scrotum without a palpable lump is a common presentation. This pattern is frequently associated with a varicocele, but can also arise from chronic epididymitis or, occasionally, referred pain from the lower back, hip, or abdomen.
Referred Pain: Pain perceived in the testicles can originate from structures elsewhere in the body. Kidney stones, inguinal hernias, and musculoskeletal problems in the groin or lower back can all produce referred testicular pain. A thorough clinical history and, where appropriate, imaging of the abdomen and pelvis may be required to identify the source.
How Scrotal Ultrasound Works
High-frequency scrotal ultrasound is the gold standard imaging modality for evaluating testicular lumps and pain [3]. It is painless, non-invasive, and uses no ionising radiation.
The examination uses a high-frequency linear probe (typically 10–18 MHz) to produce detailed, real-time images of the testicles, epididymides, and surrounding scrotal structures. The high frequency provides exceptional spatial resolution, allowing the sonographer to identify structures just a few millimetres in size.
Colour Doppler Ultrasound is an essential component of the examination. By detecting the movement of red blood cells, Doppler imaging maps blood flow within the testicular vessels in real time. This is critical for:
- Testicular torsion: Absent or markedly reduced blood flow to the affected testicle confirms torsion. This is a surgical emergency.
- Epididymo-orchitis: Increased blood flow (hyperaemia) to the epididymis and testicle is the hallmark of inflammation.
- Varicocele: Doppler demonstrates dilated veins and reversal of blood flow during the Valsalva manoeuvre (bearing down).
- Tumour vascularity: Abnormal internal blood flow patterns within a solid mass raise the suspicion of malignancy.
The key clinical question ultrasound answers is whether a lump is intratesticular or extratesticular, and whether it is solid or cystic. Intratesticular solid lesions are malignant until proven otherwise; extratesticular cystic lesions are almost invariably benign. This distinction alone resolves the clinical uncertainty for the vast majority of patients.
⚠ When to Book a Routine Scan vs Seek Urgent Assessment
| Symptom | Recommended Action |
|---|---|
| Sudden, severe testicular pain | **Go to A&E immediately** |
| New painless lump on the testicle | Book urgent scan (within days, not weeks) |
| Gradual swelling with tenderness and warmth | Book urgent scan (same day or next day) |
| Dull ache or scrotal heaviness | Book routine scan |
| Soft, painless lump separate from testicle | Book routine scan |
| Scrotal swelling without pain | Book routine scan |
Comparing Testicular Conditions
| Condition | Typical Symptoms | Urgency | Primary Imaging |
|---|---|---|---|
| **Testicular Torsion** | Sudden, severe pain; nausea; high-riding testicle | **Immediate (A&E)** | Doppler Ultrasound |
| **Testicular Cancer** | Painless, hard intratesticular lump | Urgent (within days) | Scrotal Ultrasound |
| **Epididymal Cyst / Spermatocele** | Painless, soft extratesticular lump | Routine | Scrotal Ultrasound |
| **Hydrocele** | Diffuse scrotal swelling, usually painless | Routine | Scrotal Ultrasound |
| **Epididymo-orchitis** | Gradual pain, swelling, warmth, tenderness | Urgent | Scrotal Ultrasound |
| **Varicocele** | Dull ache, heaviness, left-sided; "bag of worms" feel | Routine | Doppler Ultrasound |
From Our Practice
[SUGGESTED — verify with clinician]
At IUS London, a common presentation we encounter is a man in his 30s or 40s who has noticed a soft, slightly tender swelling on the left side of his scrotum — most noticeable after a long day on his feet or after exercise. His primary concern, understandably, is testicular cancer. On high-resolution Doppler ultrasound, we frequently identify a grade II–III varicocele with no solid intratesticular lesion. Being able to show the patient the real-time Doppler images — demonstrating the dilated veins and the reversal of flow on Valsalva — and explain that there is no tumour present provides immediate, profound reassurance. This is one of the most clinically valuable aspects of private ultrasound access: the ability to move from anxiety to a definitive, evidence-based answer within a single appointment, rather than waiting weeks through a GP referral pathway.
Book Your Private Scrotal Ultrasound Scan
If you have noticed a new lump, swelling, or unexplained pain in your testicles, do not delay seeking professional advice. The odds are strongly in your favour that the cause is benign — but an accurate diagnosis is essential, and early assessment is always the right decision.
At IUS London, we offer rapid access to premium, high-resolution private scrotal ultrasound scans performed by HCPC-registered consultant sonographers in a comfortable, discreet environment in Kensington, London. Results are available on the day.
Book your Private Scrotal Ultrasound Scan and get the clarity you deserve.
References
1. Chiba, K., et al. (2016). Varicocele and male infertility: current evidence and management. Reproductive Medicine and Biology, 15(4), 201–209. https://doi.org/10.1007/s12522-016-0234-z
2. Singla, N., et al. (2025). Testicular Germ Cell Tumors: A Review. JAMA, 333(1), 68–78. https://doi.org/10.1001/jama.2024.24053
3. Wang, C. L., et al. (2019). ACR Appropriateness Criteria® Acute Onset of Scrotal Pain — Without Trauma, Without Antecedent Mass. Journal of the American College of Radiology, 16(5S), S38–S43. https://doi.org/10.1016/j.jacr.2019.02.016
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