A varicocele looks like a cluster of swollen, twisted veins sitting above or around one testicle, often described as a “bag of worms” beneath the skin of the scrotum. Not all varicoceles are visible, though. Smaller ones can only be felt by touch or detected on ultrasound, while larger ones create a noticeable bluish, lumpy mass that changes size depending on your position and activity.
The “Bag of Worms” Appearance
The classic visual sign is a soft, irregular mass of dilated veins above the testicle. The veins bunch together and twist over one another, creating a lumpy texture under the skin that genuinely resembles a small bag of worms. The mass typically sits on the left side of the scrotum, though it can occur on either side or both. When the veins are large enough, you may see them bulging slightly through the scrotal skin, sometimes with a bluish or purplish tint.
What’s actually happening is that blood flowing away from the testicle gets backed up in the veins, causing them to widen and swell. Healthy scrotal veins are too small to see or feel. Once they dilate, they become soft, compressible cords you can roll between your fingers. The texture is distinctly different from the firm, smooth surface of the testicle itself or the tube-like structure of the epididymis behind it.
How Size Changes With Position
One of the most telling features of a varicocele is that it changes depending on what you’re doing. When you stand up, gravity pulls blood downward into the dilated veins, making them fuller and more visible. When you lie down, the blood drains back toward the body, and the swelling often shrinks or disappears entirely. This positional change is a hallmark that helps distinguish a varicocele from other scrotal lumps.
Bearing down, like straining during a bowel movement, also makes the veins swell more noticeably. Doctors use this during exams by asking you to take a deep breath, hold it, and push down (called a Valsalva maneuver). The increased abdominal pressure temporarily prevents blood from draining out of the scrotal veins, making even subtle varicoceles easier to see and feel.
The Three Grades of Varicocele
Varicoceles are classified into three grades based on how detectable they are:
- Grade I: Not visible and not felt under normal conditions. Only detectable when you bear down during an exam.
- Grade II: Can be felt at rest when standing, but not visible through the skin.
- Grade III: Clearly visible on exam without any need for straining or special positioning.
Most people searching “what does a varicocele look like” are noticing something they can see or feel and trying to figure out what it is. If you can see twisted, rope-like veins above your testicle that become more prominent when you stand or strain, that’s consistent with a Grade III varicocele. If you feel soft, squishy cords but can’t see anything, you’re likely dealing with a Grade II.
What It Looks Like on Ultrasound
When a varicocele is too small to see or feel reliably, a scrotal ultrasound can confirm it. On the screen, dilated veins appear as dark, winding channels clustered near the testicle. The key measurement is vein diameter: veins wider than about 3 millimeters are generally considered abnormal, though some research suggests the threshold for healthy veins may extend up to 3.7 or 3.8 millimeters. The ultrasound also checks whether blood is flowing backward in the veins, which confirms the underlying valve problem causing the varicocele.
Effect on Testicle Size
Over time, a varicocele can cause the affected testicle to shrink, a condition called testicular atrophy. This is sometimes the most obvious visual change, particularly in teenagers who develop varicoceles around puberty. The testicle on the affected side may look noticeably smaller than the other one. This size difference is one of the main reasons doctors recommend treatment, because a shrinking testicle signals that the blood pooling is interfering with normal testicular function and sperm production.
How It Differs From Other Scrotal Lumps
Several other conditions can cause lumps or swelling in the scrotum, and they look and feel quite different from a varicocele.
A hydrocele is a collection of fluid around the testicle. It feels smooth and firm rather than lumpy, and if you hold a flashlight against the swelling in a dark room, light passes through it because it’s fluid-filled. A varicocele won’t transilluminate like this because it’s made of blood-filled veins, not clear fluid.
A spermatocele is a small, fluid-filled cyst that forms near the top of the testicle. It feels like a distinct, round, pea-sized lump, very different from the tangled, worm-like texture of dilated veins.
The key distinguishing feature of a varicocele is its response to position and straining. No other common scrotal mass swells when you stand and bear down, then flattens when you lie on your back. If you notice a lump that behaves this way and has that characteristic ropy, soft texture, a varicocele is the most likely explanation.