Published on:
March 6, 2026
Finding a lump on your testicle can be an alarming experience. Your mind may immediately jump to the worst-case scenario, but the reality is that the vast majority of testicular lumps are benign. Still, any new lump or swelling in the scrotum warrants proper investigation — and a scrotal ultrasound is almost always the first imaging test your doctor will recommend. Understanding what this scan can and cannot tell you is essential for managing expectations, reducing anxiety, and making informed decisions about your health.
In this guide, we explore the capabilities and limitations of scrotal ultrasound, walk you through what to expect during the procedure, and explain the steps that may follow if something unusual is detected. Whether you have already been referred for a scan or are simply trying to decide whether to see a doctor, this article aims to give you the clarity you need.
Testicular cancer is the most common cancer in men aged 15 to 49 in the United Kingdom, yet it is also one of the most treatable when caught early. While most lumps turn out to be harmless — caused by cysts, varicoceles, or minor infections — the only way to distinguish a benign lump from a potentially malignant one is through proper medical assessment. Delaying evaluation can mean missing an early-stage cancer that would otherwise be straightforward to treat.
Beyond cancer, testicular lumps can indicate conditions that benefit from prompt attention. Testicular torsion, for example, is a surgical emergency in which the blood supply to the testicle becomes twisted and cut off. Epididymitis, an infection or inflammation of the tube behind the testicle, may require antibiotics. Hernias, hydroceles, and varicoceles each have their own treatment pathways. The key message is simple: if you notice something new or different, get it checked. A visit to a men's health GP is the logical first step and can usually be arranged quickly.
A scrotal ultrasound — sometimes called a testicular ultrasound — is a non-invasive imaging examination that uses high-frequency sound waves to create detailed pictures of the structures inside the scrotum. It is the first-line imaging modality recommended by urological guidelines worldwide for evaluating scrotal symptoms, and it is widely considered the gold standard for initial assessment.
The scan is performed by a trained sonographer or radiologist who places a small, handheld transducer against the skin of the scrotum. A water-based gel is applied to help transmit the sound waves, which bounce off internal tissues and are converted into real-time images on a monitor. Modern ultrasound machines can generate remarkably detailed images, often identifying structures as small as a few millimetres in diameter.
Two primary ultrasound modes are typically used together. Grey-scale ultrasound provides structural detail, showing the size, shape, and internal characteristics of any mass. Colour Doppler ultrasound maps blood flow within the testicle and surrounding structures, which can be crucial in distinguishing between different types of lesion. If you would like to learn more about the broader scope of diagnostic imaging we offer, our general ultrasound page provides a helpful overview.
One of the most important tasks of a scrotal ultrasound is determining exactly where the lump is located. A mass within the testicle itself (intratesticular) carries a higher probability of malignancy than one outside the testicle (extratesticular). Research published in the National Center for Biotechnology Information confirms that localisation is the single most important factor in characterising a scrotal mass. The scan will also measure the lump precisely, providing a baseline that can be compared if follow-up imaging is needed later.
Ultrasound is exceptionally good at differentiating between solid masses and fluid-filled structures. A simple cyst — a fluid-filled sac — will appear as a well-defined, dark (anechoic) area with thin walls and no internal blood flow. A solid mass, on the other hand, will typically appear brighter (echogenic) and may have a more irregular outline. This distinction alone can provide considerable reassurance, as simple cysts are virtually always benign.
Many scrotal findings on ultrasound have a characteristic appearance that allows a confident benign diagnosis. These include:
If a solid, intratesticular mass is identified, ultrasound can highlight several features that raise suspicion for malignancy — including irregular margins, heterogeneous internal echoes, and increased blood flow on Doppler imaging. According to the American Cancer Society, ultrasound is often the first test performed when testicular cancer is suspected. It is highly sensitive, meaning it is very unlikely to miss a significant lesion.
Colour Doppler ultrasound is invaluable in the emergency setting. In suspected testicular torsion, the scan can demonstrate reduced or absent blood flow to the affected testicle, guiding the decision for emergency surgery. It can also reveal increased blood flow associated with infection or inflammation (epididymo-orchitis), helping clinicians distinguish between conditions that require very different treatments.
This is perhaps the most important limitation to understand. While ultrasound is superb at detecting suspicious masses, it cannot provide a tissue diagnosis. In other words, it can tell your doctor that a lump looks worrying, but it cannot confirm whether that lump is cancerous — or, if it is, what type of cancer it might be. A definitive diagnosis of testicular cancer requires histological examination, which means removing the testicle (radical inguinal orchidectomy) and examining the tissue under a microscope. Unlike many other cancers, a needle biopsy is generally not performed on testicular masses due to the risk of spreading malignant cells.
A study published in PMC highlights that while conventional ultrasound supplemented by colour Doppler is highly sensitive for detecting lesions, it has limitations in definitively characterising their nature. Newer techniques such as contrast-enhanced ultrasound and elastography are improving diagnostic accuracy, but they are not yet universally available.
Some benign conditions — such as Leydig cell tumours, focal orchitis, or small areas of testicular infarction — can mimic the ultrasound appearance of malignant tumours. Equally, certain malignant lesions may have a deceptively benign appearance. When the imaging is ambiguous, your doctor may recommend short-interval follow-up scans, blood tests for tumour markers (such as AFP, beta-hCG, and LDH), or MRI to gain additional information before deciding on a management plan.
Even when a mass is highly suspicious for malignancy, ultrasound of the scrotum alone does not reveal whether cancer has spread beyond the testicle. Staging requires additional investigations — typically a CT scan of the chest, abdomen, and pelvis, along with blood tests. Scrotal ultrasound is a vital first step, but it is only one piece of the diagnostic puzzle.
Although ultrasound technology has advanced enormously, there remains a resolution limit. Very small or diffuse lesions — particularly conditions like carcinoma in situ (also known as germ cell neoplasia in situ) — may not produce a visible abnormality on ultrasound. This is why clinical correlation, including physical examination and blood tests, remains essential even when an ultrasound appears normal.
If you have never had a scrotal ultrasound before, it is entirely natural to feel a little apprehensive. Here is what you can expect. The examination is performed in a private room with you lying on your back. You will be asked to lower your trousers and underwear, and a towel will be draped to maintain your dignity as much as possible. Warm gel is applied to the scrotum, and the sonographer gently moves the transducer over the skin.
The scan is painless for most people, though there may be mild discomfort if the area is already tender or swollen. The entire examination usually takes between 15 and 30 minutes, depending on the complexity of the findings. You can return to normal activities immediately afterwards — there is no recovery time, no radiation, and no injections.
During the scan, the sonographer will systematically examine both testicles, the epididymis on each side, and the surrounding structures. They may ask you to cough or bear down (a Valsalva manoeuvre) to assess for varicoceles. Images are captured and documented, and a formal report is generated — usually by the sonographer or a supervising radiologist — which is then sent to your referring doctor.
The pathway after a scrotal ultrasound depends entirely on the findings. If the scan reveals a clearly benign condition — such as a simple cyst, hydrocele, or varicocele — your doctor may reassure you and discuss whether any treatment is needed for symptom relief. Many benign scrotal conditions require no treatment at all.
If the ultrasound identifies a suspicious solid mass within the testicle, you will typically be referred urgently to a urologist. The standard diagnostic pathway in the UK involves a two-week-wait cancer referral, during which you will have blood tests for tumour markers and likely a CT scan for staging. If malignancy is confirmed or strongly suspected, surgical removal of the affected testicle through the groin (radical inguinal orchidectomy) is the standard next step. It is worth noting that losing one testicle does not usually affect fertility or testosterone levels significantly, as the remaining testicle can compensate.
In cases where the findings are indeterminate — not clearly benign but not definitively suspicious either — your doctor may recommend a period of surveillance with repeat ultrasound in six to twelve weeks. This "watch and wait" approach is safe for small, equivocal lesions, as any malignant growth would be expected to show a change in size or character over time. Additional investigations, including an MRI of the scrotum, may also be considered. If you are concerned about your broader health profile, complementary screening such as prostate screening may also be worth discussing with your GP, particularly if you are over 50.
You should see a doctor if you notice any of the following:
Regular self-examination is the simplest way to become familiar with what is normal for you. Most experts recommend checking your testicles once a month, ideally after a warm bath or shower when the scrotal skin is relaxed. Use both hands to gently roll each testicle between your fingers, feeling for any hard lumps, smooth bumps, or changes in size or firmness. If anything feels different from the last time you checked, make an appointment without delay.
It is also important to remember that not all testicular symptoms are related to lumps. Pain, swelling, and changes in size can be caused by infections, fluid collections, or even referred pain from other areas. A thorough clinical assessment — combining history, examination, and ultrasound where indicated — is the best way to reach an accurate diagnosis.
No. A scrotal ultrasound is a non-invasive, painless procedure for most men. The sonographer applies warm gel and gently moves a small probe over the skin. If the area is already sore or inflamed, you may experience mild discomfort, but the scan itself does not involve any needles, incisions, or radiation. Most men describe it as slightly awkward rather than painful.
A scrotal ultrasound can identify features that are suspicious for cancer — such as a solid, irregularly shaped mass within the testicle with increased blood flow — but it cannot provide a definitive cancer diagnosis. Only histological examination of the tissue (typically after surgical removal) can confirm whether a mass is malignant. Ultrasound is best understood as a highly sensitive screening and localisation tool rather than a definitive diagnostic one.
The scan typically takes between 15 and 30 minutes, depending on the findings and the complexity of the examination. You do not need any special preparation, fasting, or recovery time. You can return to your normal activities immediately after the scan.
The majority of testicular lumps are benign. Studies suggest that only a small proportion of scrotal masses referred for ultrasound turn out to be malignant. However, the risk is higher for lumps located within the testicle itself compared with those in the surrounding structures. Regardless of the statistical odds, any new lump should be assessed by a healthcare professional to rule out serious pathology.
In most cases, a referral from a GP or specialist is needed to arrange a scrotal ultrasound. Your doctor will assess your symptoms, perform a physical examination, and determine whether imaging is appropriate. Some private clinics offer self-referral ultrasound services, which can be a convenient option if you want a rapid assessment without waiting for an NHS appointment.
The information provided in this article is for educational purposes only and is based on NHS recommendations. It is not a substitute for professional medical advice. Always consult your doctor or a qualified healthcare provider for advice on medical conditions or treatments.
Our medical centre is at 36 Spital Square, E1 6DY, City of London.
