There are three common types of skin cancer and at least nine recognized rare types, bringing the total to a dozen or more distinct diseases that originate in the skin. The three main types, basal cell carcinoma, squamous cell carcinoma, and melanoma, account for the vast majority of cases. But several rarer cancers also start in the skin, and they behave very differently from one another.
The Three Common Types
All skin cancer begins in the epidermis, the outermost layer of skin. Which type you get depends on which cell goes wrong. The epidermis contains three kinds of cells: flat squamous cells on the surface, round basal cells beneath them, and melanocytes deeper down, which produce the pigment that gives skin its color. Each cell type can become cancerous, producing a different disease.
Basal cell carcinoma (BCC) is the most common skin cancer and the most common cancer of any kind. It grows in the round basal cells and almost never spreads to distant parts of the body. It can usually be cured with treatment, though it sometimes leaves scars and can be costly to manage.
Squamous cell carcinoma (SCC) is the second most common. It arises in the flat cells on the skin’s surface and is also highly treatable when caught early. In a small percentage of cases, roughly 4 to 5%, it spreads to nearby lymph nodes. That risk climbs when tumors are large, deep, or located on the lip or ear.
Melanoma is the third most common but the most dangerous. It starts in the melanocytes and has a strong tendency to spread to vital organs like the brain and liver. An estimated 112,000 new cases will be diagnosed in the U.S. in 2026 alone. When caught while still localized to the skin, melanoma has a five-year survival rate of about 98%. Once it spreads to distant organs, that number drops to around 16%.
Rare Skin Cancers
Beyond the big three, the Skin Cancer Foundation recognizes at least nine additional types. These are uncommon individually, but collectively they represent a meaningful number of diagnoses each year. The most notable include:
- Merkel cell carcinoma (MCC): An aggressive cancer that forms painless, fast-growing bumps, most often on sun-exposed skin of the head or neck. It tends to spread quickly. The Merkel cell polyomavirus, which lives on normal skin, plays a role in many cases. People over 50, those with lighter skin, and those with weakened immune systems face the highest risk.
- Kaposi sarcoma: Develops from cells lining blood vessels or lymph vessels. A “classic” form appears slowly in older men of European or Mediterranean descent and rarely causes serious problems. A more aggressive form is linked to immune suppression, particularly HIV infection.
- Dermatofibrosarcoma protuberans (DFSP): A slow-growing tumor in the deeper layers of skin. It rarely spreads to distant sites but tends to grow into surrounding tissue, making complete surgical removal important. A technique called Mohs surgery, where tissue is removed one thin layer at a time and checked under a microscope, is often used for larger tumors.
- Cutaneous T-cell lymphoma: A cancer of immune cells that shows up on the skin as flat, scaly, or raised patches that can look pink, red, brown, or gray. Patches typically appear on skin that doesn’t get much sun, like the upper thighs, breasts, or buttocks. One aggressive subtype, Sézary syndrome, can eventually cause a rash over the entire body.
- Sebaceous carcinoma: Originates in the oil-producing glands of the skin, most commonly around the eyelids.
- Microcystic adnexal carcinoma (MAC): A locally invasive cancer that most often appears on the face, particularly around the lips and near the eyes, in older adults. It grows deep into the skin and can invade fat, muscle, or even bone, but distant spread is rare.
- Extramammary Paget’s disease (EMPD): A slow-growing cancer that typically affects the skin of the groin or genital area.
A few other rare types round out the list, including acral lentiginous melanoma (a subtype of melanoma that appears on palms, soles, or under nails and is the most common melanoma subtype in people with darker skin) and undifferentiated pleomorphic sarcoma.
Why the Count Isn’t a Simple Number
Depending on how finely you divide them, the number of recognized skin cancer types ranges from about a dozen to several dozen. Some sources group all melanoma together as one type, while others count its subtypes (like acral lentiginous or nodular melanoma) separately. Lymphomas of the skin include multiple subtypes as well. A practical answer for most people is that there are three common types and roughly nine to ten rare types that are well characterized and widely recognized.
What Raises Your Risk
Ultraviolet radiation from the sun or tanning beds is the biggest modifiable risk factor for most skin cancers. But not all skin cancers appear on sun-exposed areas, which tells researchers that other factors matter too.
A weakened immune system significantly raises risk across multiple types. This includes people who take immune-suppressing medications after an organ transplant and those living with HIV. A family history of skin cancer, particularly in a parent or sibling, also increases your likelihood. For Merkel cell carcinoma and Kaposi sarcoma specifically, certain viruses play a direct role in triggering the cancer.
Lighter skin that burns easily is a risk factor for most types, though people of any skin color can develop skin cancer. In people with darker skin, cancers sometimes appear in less expected locations, like the palms, soles, or lower legs, which can delay diagnosis.
How Detection Changes Outcomes
The survival gap between early and late detection is enormous, especially for melanoma and Merkel cell carcinoma. Melanoma caught before it spreads beyond the skin has a five-year survival rate near 98%. Once it reaches regional lymph nodes, that drops to about 60%. Basal and squamous cell carcinomas are almost always curable when found early, but they can cause significant tissue destruction if ignored.
Any new bump, patch, or mole that changes in size, color, or shape deserves attention. For rare types, the challenge is that they often don’t look like what most people think of as skin cancer. Cutaneous lymphoma can mimic eczema. Merkel cell carcinoma can look like a harmless cyst. Sebaceous carcinoma near the eye can be mistaken for a stye. When a skin change doesn’t heal or keeps growing, that pattern itself is the warning sign worth acting on.