Little black dots under skin on fingers

You know what melanoma looks like, right? You’ve probably seen the iconic pictures of a big, brown mole with jagged edges. And while that’s the image that most of us conjure when we think of melanoma, it’s not the only sign of this skin cancer. Some are far less obvious. Melanoma may not be brown; it may not be a mole—it might not even appear on your skin! We talked to top skin cancer experts to pinpoint the sneakiest forms of malignant melanoma.

An Unevenly Pigmented Patch of Skin

In people of color, melanoma doesn’t always show up as a mole. Sometimes it just looks like a dark lesion or patch of dark skin. And it often surfaces in places you wouldn’t expect melanoma to grow: the soles of your feet or the palms of your hands. Melanoma in dark skin is far less common than it is in fair complexions, but when it does happen, it’s often deadlier because it’s typically found at a later stage. One more reason to be attuned to any changes in your body!

A Dark Line in Your Nail

“When melanoma pops up on your nails, it looks more like a bruise under your nail plate,” says Heather Woolery-Lloyd, M.D., director of the skin of color division in the department of dermatology of the University of Miami. Called subungual melanoma, which translates to “melanoma beneath a fingernail or toenail,” this type typically shows up as a dark, vertical line down the length of your nail. Over time, the line may spread, covering more of your nail. It’s also known as acral lentiginous melanoma (ALM), melanoma on your hands, feet, or nails.

Pigmentation in Your Gums

A dark spot on your gums can signal mucosal melanoma, an extremely rare form of the skin cancer that appears on mucus membranes—in your mouth, your nose, genitals, and even within your respiratory and GI tracts. Mucosal melanoma accounts for 1.4% of all melanoma cases, but it’s particularly lethal compared to other forms of the disease. Aside from pigmented lesions in these mucous-lined areas, other symptoms may include pain, bleeding, lumps, or changes in your GI tract such as diarrhea or constipation.

A Mole With a Halo

A halo might have a positive association (angels!), but when there’s a white ring surrounding a mole, you may want to show it to a dermatologist. In rare cases, the white circle around a mole can signify melanoma. “Depigmentation can appear around normal moles, too, but it can suggest there’s something going on with your immune system,” says Dr. Woolery-Lloyd. So, it’s worth checking it out, especially if the mole with a halo is oddly shaped and asymmetrical.

A Colorless Bump

We tend to think of melanomas as brown or black in color, but they can be pink or reddish, or lack color all together, appearing as a flesh-colored spot or bump, says Ava Shamban, M.D., assistant clinical professor of dermatology at UCLA-Geffen School of Medicine in Los Angeles. “It’s called amelanotic melanoma,” she explains. It can be particularly tricky to diagnose because it often looks like other forms of skin cancer such as basal cell carcinomas, or even just a cystic pimple or scar tissue.

A Load of Funny-Looking Moles

If you’re blanketed in oddly-shaped moles, you have a greater chance of developing melanoma—12 times the risk if you have just 10 atypical moles, according to the Skin Cancer Foundation. “It’s called dysplastic nevi syndrome, which means you have a lot of moles that have some irregular features,” says Ellen Marmur, M.D., Mohs surgeon and associate clinical professor of dermatology at The Mount Sinai School of Medicine in New York City. “Many of us will have dysplastic nevi that are considered mild and moderate, but anything that’s severely dysplastic will become melanoma if left untouched.”

Any Sign of Blood

A new or existing spot that suddenly starts to bleed is a red flag for melanoma or another type of skin cancer. “I once had a patient with melanoma that looked more like a bloody skin tag, as if it had been traumatized,” says Dr. Woolery-Lloyd. “I wasn’t even thinking melanoma at first.” Bottom line: Any mole that’s itching, bleeding, or oozing needs to be checked out by a physician, ideally a board-certified dermatologist, trained to spot these rare forms of melanoma.

A Teeny-Tiny New Spot

You may have heard to flag moles that have a diameter larger than a pencil eraser (1/4-inch). That’s pretty hard to miss, right? But that doesn’t mean you should ignore the little stuff. “Even though we think of malignant melanoma as being large, it can appear initially as a small, dark spot that just looks creepy,” says Dr. Shamban. Melanomas can be tiny black dots that are no bigger than a pen tip. Any new or existing moles that stand out from the rest in color, shape, or size, should be looked at by a physician.

You Have a Dark Spot in Your Eye

Sometimes melanoma is not on your skin, but inside your eye (a.k.a. uveal melanoma). This type is particularly tricky because the tumor isn’t readily visible to, well, the naked eye. You’d need an ophthamologist to spot it. But you may notice a darker spot on the iris of your eye or a change in the shape of your pupil. Other symptoms of uveal melanomas include blurry vision, loss of vision, and floaters (those golden flecks that float around your vision). If you’re experiencing any of these, get thee to an eye doc, stat.