Testicular Ultrasound: When Do You Need One?
A testicular lump is the most obvious reason — but scrotal pain, swelling, a change in size, or a fertility investigation are all valid reasons to book a scrotal ultrasound. A consultant sonographer explains what the scan looks for and what to expect.
- Men's Health
- Updated July 2026
When Is a Testicular Ultrasound Needed?
A scrotal ultrasound is the first-line imaging investigation for any symptom or finding in the scrotum or testes. It is non-invasive, uses no radiation, and provides real-time images of the testicular parenchyma, epididymis, and surrounding structures — including colour Doppler assessment of blood flow, which is essential for distinguishing between conditions that look similar on clinical examination but require very different management.
1. A Testicular Lump or Swelling
Any new lump in the scrotum should be assessed by ultrasound. The majority of scrotal lumps are benign — epididymal cysts, hydroceles, and varicoceles account for most presentations. However, a solid mass within the testicular parenchyma itself (as opposed to the epididymis or surrounding structures) is testicular cancer until proven otherwise, and requires same-day urology referral. Ultrasound distinguishes between these with high accuracy. It cannot be done reliably by clinical examination alone.
2. Scrotal or Testicular Pain
Acute scrotal pain is a urological emergency until testicular torsion is excluded. Torsion — twisting of the spermatic cord — cuts off the blood supply to the testis and causes irreversible ischaemia within 4–6 hours. If you have sudden, severe testicular pain, go to A&E immediately rather than booking a private scan. Colour Doppler ultrasound is the investigation used to confirm or exclude torsion, and it needs to happen in a hospital setting where surgical intervention is immediately available.
Subacute or chronic scrotal pain — pain that has been present for days or weeks rather than hours — is a different clinical picture. Epididymo-orchitis (infection/inflammation of the epididymis and testis) is the most common cause and is readily identified on ultrasound. A private scan is appropriate for this presentation.
3. Change in Testicular Size
A testis that has become noticeably larger or smaller over weeks or months warrants investigation. Gradual enlargement may indicate a slow-growing tumour; gradual atrophy can follow previous infection, torsion, or varicocele. Ultrasound measures both testes and compares them, providing a baseline for follow-up if needed.
4. Fertility Investigation
Varicocele — enlargement of the pampiniform plexus veins in the scrotum — is present in approximately 15% of men in the general population and in 35–40% of men presenting with primary infertility. It is the most common correctable cause of male subfertility. Varicoceles are not always palpable on clinical examination, particularly small or subclinical varicoceles, and ultrasound with Doppler is the definitive investigation. A scrotal ultrasound also assesses for epididymal obstruction, which can cause azoospermia or severe oligospermia.
5. Trauma
Scrotal trauma — from sport, a fall, or a direct blow — can cause testicular rupture (disruption of the tunica albuginea), haematocele (blood in the scrotal sac), or epididymal injury. Ultrasound is the first-line investigation for scrotal trauma and determines whether surgical exploration is needed. A haematocele with testicular rupture requires urgent surgery; a simple haematocele without rupture can usually be managed conservatively.
6. Incidental Finding on Self-Examination
Testicular self-examination is recommended monthly for men aged 15–40. Any new finding — a lump, an area of firmness, a change in texture — that was not there before should be assessed by ultrasound within a few days, not monitored at home for weeks. The reassurance provided by a normal scan is clinically valuable; the early identification of a tumour is potentially life-saving.
What Does a Testicular Ultrasound Show?
A scrotal ultrasound at Sonoworld assesses both testes and epididymides in greyscale and colour Doppler. The report documents:
- Testicular size and volume (both sides, compared)
- Testicular echotexture — homogeneous (normal) or heterogeneous (abnormal)
- Any focal lesion — location, size, echogenicity, vascularity
- Epididymis — size, echogenicity, cysts
- Extratesticular findings — hydrocele, varicocele, hernia sac
- Doppler flow — present and symmetric (normal), absent or asymmetric (abnormal)
Findings are reported using standardised terminology. The report is sent the same day and includes a clinical recommendation — whether the finding is benign and requires no further action, or whether onward referral is indicated and to whom.
From Our Practice
The most common presentation in our scrotal ultrasound casebook is a man aged 25–45 who has found a lump and wants to know what it is before deciding whether to see his GP. In the majority of cases, the lump is an epididymal cyst — a benign, fluid-filled structure in the epididymis that requires no treatment. The scan takes 20 minutes, the finding is explained verbally in the room, and the patient leaves with a written report that confirms the diagnosis. The anxiety that drove the booking is resolved the same afternoon.
The pattern that requires a different response is the solid intratesticular mass. When the greyscale images show a hypoechoic lesion within the testicular parenchyma and the Doppler shows increased vascularity within it, the clinical picture changes. The patient is told clearly what the scan has found, what it means, and what needs to happen next. A referral letter is prepared and the patient is advised to contact their GP or attend a urology clinic the same day. The written report uses the language that the receiving clinician will need to act on it promptly.
The third pattern is the man who has been aware of a scrotal change for months and has been hoping it would resolve. It rarely does. The earlier the scan, the earlier the answer — and in the case of testicular cancer, which has a five-year survival rate above 95% when caught at stage 1, the earlier the answer, the better the outcome.
Observations above are drawn from composite patterns across our patient population, not from any individual case.
Testicular Ultrasound FAQs
Is a testicular ultrasound painful?
No. A testicular ultrasound is non-invasive and painless. Warm gel is applied to the scrotum and a small probe is moved gently over the skin. There are no needles, no compression, and no instruments inserted into the body. The scan takes approximately 20 minutes.
How quickly will I get my results?
Verbal results are given in the room immediately after the scan. The written report is sent the same day by email. If the scan finds something that requires urgent action, you will be told clearly in the room and the report will be prepared immediately.
Do I need to prepare for a testicular ultrasound?
No special preparation is required. You do not need to fast or have a full bladder. Wear comfortable, loose clothing. The scan is performed with you lying on an examination couch.
What is the difference between an epididymal cyst and a testicular tumour?
An epididymal cyst is a benign, fluid-filled structure in the epididymis — the coiled tube that sits behind the testis. It is outside the testis itself, appears as a smooth, anechoic (dark) round structure on ultrasound, and requires no treatment. A testicular tumour is a solid mass within the testicular parenchyma — inside the testis. It typically appears as a hypoechoic (darker than the surrounding tissue) mass with increased blood flow on Doppler. These two findings look and feel similar on clinical examination but are completely different on ultrasound — which is why the scan is the definitive investigation.
Sources
- Dogra, V.S., et al. "Sonography of the scrotum." Radiology 227.1 (2003): 18–36.
- Kapoor, A. "Epididymo-orchitis." BMJ 344 (2012): e3577.
- Dohle, G.R., et al. "EAU Guidelines on Male Infertility." European Urology 48.5 (2005): 703–711.
- Sonoworld clinical imaging team. Composite practice patterns — Sonoworld Diagnostic Services, Marylebone, London. July 2026.
Book a Testicular Ultrasound Scan
£235 · Same-day appointments available · No GP referral needed · Verbal results in the room · Written report the same day
29 Weymouth Street, Marylebone, London W1G 7DB | 020 3633 4902
