Two years ago, my dermatologist found a suspicious spot on my shoulder during a routine skin check. She said it looked like basal cell carcinoma and wanted to biopsy it immediately. I sat there confused. I’d heard of melanoma because everyone talks about that one, but basal cell carcinoma? I had no idea there were multiple types of skin cancer, each with different risks and treatments.

That tiny spot turned out to be benign, but the experience sent me down a research spiral. I learned that skin cancer isn’t just one disease. There are four main types, each starting in different skin cells, appearing differently, and requiring different treatment approaches. Understanding these differences matters because early detection saves lives.

The Four Main Types of Skin Cancer

Skin cancer develops when skin cells grow abnormally and uncontrollably. The type of skin cancer is determined by which cells become cancerous. The four main types are basal cell carcinoma, squamous cell carcinoma, melanoma, and Merkel cell carcinoma.

These four types differ dramatically in frequency, appearance, aggressiveness, and treatment requirements. Understanding these differences helps you know what to look for during self-exams and when to see a dermatologist.

Basal Cell Carcinoma

Basal cell carcinoma (BCC) is the most common type of skin cancer, accounting for about 80% of all skin cancer cases. Approximately 3.6 million cases are diagnosed in the United States annually as of 2025.

BCC starts in the basal cells, which are found in the lowest part of the epidermis (the skin’s outer layer). These cells constantly divide to create new cells that push upward to replace dead skin cells on the surface.

What it looks like

BCC often appears as a flesh-colored, pearl-like bump or a pinkish patch of skin. It can also look like a waxy bump, a flat scaly patch, or a sore that bleeds, scabs over, heals, and then reopens in a repeating cycle.

Where it appears

BCCs typically develop on sun-exposed areas including the face, head, neck, shoulders, arms, and back. I’ve seen them most commonly on people’s noses, ears, and scalps.

How dangerous is it

BCC grows slowly and rarely spreads to other parts of the body. However, if left untreated, it can grow into nearby areas and invade bone or other tissues beneath the skin. Early treatment is important to prevent local tissue damage.

Who gets it

People with fair skin, blonde or red hair, and light eyes face higher risk. Those with extensive sun exposure history or who used tanning beds are particularly vulnerable.

I know three people who’ve had BCC removed. All three caught it early through routine dermatologist visits. The removals were simple office procedures with minimal scarring. This is why regular skin checks matter so much.

Squamous Cell Carcinoma

Squamous cell carcinoma (SCC) is the second most common skin cancer, accounting for about 20% of cases. More than 1.8 million cases are diagnosed annually in the United States.

SCC starts in squamous cells, which make up most of the epidermis’s upper layers. These are the flat cells that constantly shed as new ones form underneath.

What it looks like

SCC often appears as a firm, red nodule or a flat lesion with a scaly, crusted surface. It can look like a rough, scaly patch or a sore that doesn’t heal. Sometimes it resembles a wart or looks like a raised growth with a central depression.

Where it appears

SCC tends to form on sun-exposed skin including the face, ears, neck, arms, chest, and back. It’s particularly common on the rim of the ear, face, and backs of hands.

How dangerous is it

SCC grows faster than BCC and has a higher risk of spreading to other parts of the body, though this is still relatively uncommon if caught early. SCC can grow deep into the skin, causing significant damage and disfigurement if not treated promptly.

Who gets it

Like BCC, people with fair skin and extensive sun exposure history are at highest risk. SCC also develops more frequently in people who are immunocompromised or have had organ transplants.

My uncle had SCC removed from his ear five years ago. The dermatologist caught it early, but even so, the removal required plastic surgery to reconstruct part of his ear because the cancer had grown deeper than initially expected. This taught me that “less dangerous than melanoma” doesn’t mean harmless.

Melanoma

Melanoma is the most serious type of skin cancer, accounting for only about 1% of skin cancer cases but causing the majority of skin cancer deaths. An estimated 104,960 new melanoma cases will be diagnosed in 2025, with approximately 8,430 deaths.

Melanoma develops in melanocytes, the cells that produce melanin (the pigment that gives skin its color). Unlike BCC and SCC, melanoma can spread quickly to other organs if not caught early.

What it looks like

Melanoma often resembles a mole or may develop from an existing mole. It can appear as a dark spot that looks different from other spots on your skin. The ABCDE rule helps identify suspicious moles: Asymmetry, Border irregularity, Color variation, Diameter larger than a pencil eraser, and Evolving or changing over time.

Where it appears

Melanoma can develop anywhere on the body, even in areas not typically exposed to sun. In men, it’s most common on the back. In women, it’s often found on the legs. It can also appear under fingernails, on palms, soles of feet, or inside the mouth.

How dangerous is it

Melanoma is highly curable when caught early. However, it can be dangerous even when very small because it tends to spread to lymph nodes and distant organs. The five-year survival rate is 99% for localized melanoma but drops significantly once it spreads.

Who gets it

While more common in fair-skinned people, melanoma can affect anyone regardless of skin tone. Intense, intermittent sun exposure leading to sunburn significantly increases risk, as does tanning bed use.

My friend’s mother was diagnosed with stage 1 melanoma on her calf three years ago. Because she caught it early through routine skin checks, treatment involved only surgical removal with no additional therapy needed. She’s cancer-free now. This story drives home how critical early detection is with melanoma.

Merkel Cell Carcinoma

Merkel cell carcinoma (MCC) is the rarest skin cancer, with about 3,000 annual US cases. Despite being rare, it’s extremely aggressive. MCC develops in Merkel cells located near nerve endings in the skin.

What it looks like

MCC appears as a firm, painless lump or nodule. The lump can be flesh-colored, red, blue, or purple, often growing quickly to dime-size or larger.

Where it appears

Most MCCs appear on sun-exposed areas, particularly the face, head, neck, and arms. About half occur on the head and neck.

How dangerous is it

MCC is highly aggressive with high risk of recurring and spreading. Early detection and treatment are critical.

Who gets it

Most common in fair-skinned individuals over 50. Associated with Merkel cell polyomavirus. Immunocompromised people face elevated risk.

Any rapidly growing, painless lump should be evaluated immediately because MCC requires aggressive treatment and early intervention dramatically improves outcomes.

Prevention and Early Detection

1. Most skin cancers are caused by UV radiation from sun exposure or tanning beds. Prevention requires consistent habits.
2. Use broad-spectrum SPF 30+ sunscreen daily. Reapply every two hours outdoors. I keep sunscreen in my car, bathroom, and desk for easy access.
3. Avoid tanning beds completely. The WHO classifies them as Group 1 carcinogens, same as cigarettes.
4. Wear protective clothing including wide-brimmed hats, long sleeves, and sunglasses. UPF-rated clothing provides extra protection.
5. Seek shade during peak UV hours (10am to 4pm) when rays are strongest.
6. Perform monthly self-exams checking for new spots or changes to existing moles. Use mirrors for hard-to-see areas or ask a partner to help.
7. See a dermatologist annually for professional skin checks, especially if you have fair skin, family history, many moles, or history of severe sunburns.

Conclusion

The four main types of skin cancer are basal cell carcinoma (most common, least dangerous), squamous cell carcinoma (second most common, moderately dangerous), melanoma (rare but deadly if not caught early), and Merkel cell carcinoma (rarest and most aggressive).

One in five Americans will develop skin cancer by age 70. These aren’t rare conditions affecting only elderly people with sun damage. Skin cancer impacts people of all ages and skin tones, though risk varies by individual factors.

The good news is that most skin cancers are highly treatable when caught early. This makes prevention and early detection your most powerful tools. Sunscreen, protective clothing, avoiding tanning beds, and annual dermatologist visits can prevent most skin cancers or catch them when treatment is simplest and most effective.