Skin cancer doesn’t have one single look. It can appear as a pearly bump, a scaly patch, a dark streak under a nail, or a mole that’s changed shape. The three main types, basal cell carcinoma, squamous cell carcinoma, and melanoma, each have distinct visual features worth learning to recognize.
Basal Cell Carcinoma
Basal cell carcinoma is the most common skin cancer, and it often looks deceptively harmless. On lighter skin, it typically appears as a shiny, translucent bump with a pearly white or pinkish surface. You might notice tiny blood vessels running through or around it. Some basal cell carcinomas don’t form a bump at all. Instead, they look like a flat, white, waxy patch that resembles a scar, sometimes without a clearly defined border. Others show up as a sore that bleeds, scabs over, heals partially, then opens again.
On brown or Black skin, the pearly quality and tiny blood vessels can be harder to spot. The lesion may appear more like a dark, glossy bump or a persistent sore that won’t fully heal. Basal cell carcinomas grow slowly and rarely spread to other parts of the body, but they can damage surrounding tissue if left untreated for years.
Squamous Cell Carcinoma
Squamous cell carcinoma tends to look rougher and more textured than basal cell. Common appearances include a firm bump (or nodule) on the skin, a flat sore topped with a scaly crust, or a raised wartlike growth. The color depends on your skin tone: it can look pink, red, brown, or black. On the lips, it often starts as a rough, scaly patch that may eventually break open into a sore.
One important clue is location. Squamous cell carcinoma favors sun-exposed areas like the face, ears, hands, and forearms. But it can also develop on old scars, chronic wounds, or inside the mouth. A new sore or raised area forming on top of an existing scar is a red flag worth having checked.
Melanoma and the ABCDE Rule
Melanoma is the most dangerous form of skin cancer, and it’s also the one most people picture when they think of suspicious moles. The ABCDE rule, developed by the National Cancer Institute, outlines five warning signs:
- Asymmetry: one half of the mole doesn’t match the other.
- Border: the edges are ragged, notched, or blurred, sometimes with pigment spreading into the surrounding skin.
- Color: the mole contains multiple shades of brown, black, or tan, possibly mixed with white, gray, red, pink, or blue areas.
- Diameter: the spot is larger than about 6 millimeters (roughly the size of a pencil eraser), though melanomas can sometimes be smaller.
- Evolving: the mole has noticeably changed in size, shape, or color over the past few weeks or months.
Not every melanoma hits all five criteria, and not every mole that meets one criterion is cancer. But any mole that is changing, especially one that looks different from the rest of your moles, deserves attention.
The Ugly Duckling Sign
Beyond the ABCDE rule, there’s a simpler instinct worth trusting. Most of your moles tend to look similar to each other in color, size, and shape. If one mole stands out as clearly different from the rest, that’s called the “ugly duckling” sign, and it’s a useful reason to get a professional opinion. The mole that doesn’t fit the pattern is the one to watch.
Melanoma That Doesn’t Look Dark
Not all melanomas are dark brown or black. A subtype called amelanotic melanoma lacks the typical dark pigment. It usually appears pink or light brown, making it easy to mistake for a pimple, bug bite, or minor irritation. It’s still somewhat distinct from the surrounding skin, but because people associate melanoma with dark moles, this type often gets caught later. Any new pink or reddish bump that persists for several weeks and doesn’t heal is worth pointing out to a dermatologist.
Skin Cancer Under the Nails
Melanoma can develop under fingernails or toenails, where it usually appears as a dark vertical streak running from the base of the nail toward the tip. Over time, the nail may split, crack, or become deformed. A key warning sign is when the dark pigment spreads from the nail into the surrounding skin at the cuticle or nail fold, known as the Hutchinson sign.
This type, called subungual melanoma, is easy to dismiss as a bruise or fungal infection. Unlike a bruise, however, it doesn’t grow out with the nail over a few months. It stays in the same position or gets wider.
What It Looks Like on Darker Skin
Skin cancer is less common in people with darker skin, but it can be more dangerous when it does occur because it’s often diagnosed later. The most common form of melanoma in people with dark skin is acral lentiginous melanoma, which develops in places that get little sun: the palms of the hands, the soles of the feet, and under the nails. It can look like a dark patch on your palm or the bottom of your foot, or a dark band under a fingernail or toenail.
These are areas most people don’t think to check. If you notice a dark band appearing under a nail, particularly one that’s widening over time, that’s an important finding. Regularly checking the soles of your feet, between your toes, and your palms is a simple habit that can catch this type of cancer early.
Pre-Cancerous Spots to Watch
Actinic keratoses are rough, scaly patches of skin that haven’t become cancer yet but can progress to squamous cell carcinoma if left alone. They’re usually less than an inch across, feel like sandpaper when you run your finger over them, and range in color from pink to red to brown. Some develop a hard, wartlike surface. They show up on sun-exposed areas like the face, scalp (especially in people with thinning hair), forearms, and backs of the hands. Not all of them turn into cancer, but dermatologists typically recommend treating them as a precaution.
Growths That Look Like Cancer but Aren’t
Seborrheic keratoses are one of the most common benign growths that get mistaken for skin cancer. They’re waxy, slightly raised, painless patches that range from white to black and can appear anywhere on the body. People sometimes describe them as looking like unusual scabs that got stuck to the skin. They can look alarming, especially the darker ones, but they tend to have a “pasted on” quality that distinguishes them from melanoma.
The practical difference: seborrheic keratoses are symmetrical, uniform in color (even if that color is dark), and stable over time. Melanoma is typically asymmetrical, contains multiple colors, and changes. If a growth you assumed was a harmless keratosis starts shifting in shape or color, that assumption is worth revisiting.
Rare Types
Merkel cell carcinoma is uncommon but aggressive. It appears as a firm, painless, shiny lump on the skin, usually skin-colored, red, or purple, ranging from about a quarter of an inch to over two inches across. It often shows up on sun-exposed areas of the head, neck, arms, or legs, and its most distinguishing feature is how fast it grows. Because it can resemble a harmless cyst, any firm lump that appears and grows rapidly over weeks should be evaluated.