More Than Melanoma: Different Types of Skin Cancer

People often use the terms melanoma and skin cancer interchangeably, but they are not the same thing.  We asked Dr. Raffaele Murace, a surgeon specializing in Dermatology and Venereology at UPMC Salvator Mundi International Hospital, to help us clarify.

Dr. Murace can you tell us what is the difference between melanoma and skin cancers?

Although melanoma accounts for only 5 percent of all skin cancers (source: AIRC), it is responsible for a very high cause of death because it is the most serious and aggressive form of skin cancer. It develops from melanocytes, which are cellular elements found within the epidermis, one of the layers that make up the skin. Melanocytes are the cells that produce the pigment, which gives color to our skin, namely melanin. All other skin cancers, however, form in the basal, squamous or Merkel cells and have different causes, symptoms and courses.

What are the causes of melanoma?

When melanocytes mutate and proliferate out of control, melanoma develops. While no exact cause of all melanomas has been identified, exposure to ultraviolet (UV) rays from sunlight or tanning beds significantly increases the risk of developing some types of melanoma. Other risk factors include familiarity, heredity, phenotype (light skin, hair, and eyes), and the presence of other predisposing diseases.

Doctor, where does melanoma usually strike?

Melanomas can develop in any part of the body, most often in the areas most exposed to the sun, namely the arms, legs, back, and face. However, the tumor can also attack areas of the body with little or no sun exposure such as the scalp, genitals, palms of the hands, and soles of the feet. In rare cases then, melanoma can develop in the eyes, inside the nose, and even in the throat.

Can you tell us what are the other types of skin cancer instead?

Besides melanoma, the three main types of skin cancer are basal cell carcinoma, squamous cell carcinoma and Merkel cell carcinoma. All are formed in the epidermis, which is the upper layer of the skin.

Basal cells reside in the lower part of the epidermis, perpetuating their division to constantly generate new cells, replacing those that are naturally depleted on the skin surface. Basal cell carcinoma, also known as basalioma or basal cell epithelioma, is the most common form of skin cancer. Its typical manifestations include scarring, growths with slightly raised and rolled edges, pink growths, red spots, open sores and shiny bumps.

This type of neoplasm progresses slowly, tends to be curable, and generates minimal damage when diagnosed and treated early, i.e., it has local invasiveness. Although it rarely metastasizes beyond the site of origin, it can cause disfigurement and pose a threat if not treated properly.

Squamous cell carcinomas, also known as squamous cell or spiny cell tumors, are the second most common form of skin cancer. When detected early, they are successfully treatable.

They originate from the squamous cells of the epidermis, which are the flat cells found near the surface of the skin that are constantly renewing themselves. Squamous cell carcinoma commonly manifests as raised wart-like growths with a central depression, scaly red spots, open sores, or rough, thickened warts. Although these tumors typically appear on sun-exposed skin, they can also occur on other parts of the body, including the genitals. People who have undergone a solid organ transplant or are taking immunosuppressive drugs are also at particular risk.

Merkel cell carcinoma, which is extremely rare and aggressive, develops when malignant cancer cells form in the skin. Prolonged sun exposure and a compromised immune system can increase the risk of developing Merkel cell carcinoma. It typically manifests as a single painless lump on sun-exposed skin, such as the head, neck, arms, and legs.

Doctor, what can we do to protect ourselves from melanoma and other skin cancers?

It is critical to understand how and where each type of skin cancer tends to appear, as well as to recognize the associated risk factors. Although melanoma is less common than other skin cancers, it poses a more serious threat. Its danger lies in the fact that, if not detected and treated early, it is more likely to spread to other organs and tissues. Usually, it is diagnosed after age 65 and affects men more frequently. The main way to prevent the development of all types of skin cancers, including melanoma, is to adopt protective behaviors and undergo periodic screenings.

First of all, it is good to minimize exposure to ultraviolet rays, especially for fair-skinned people, avoiding using tanning beds and sunbathing during the hottest hours (10 a.m. to 4 p.m.). Fundamental is sunscreen, which should always be put on before exposure to the sun, with an SPF of at least 30 or better 50, repeating the application about every two hours. Another aspect that should not be underestimated is self-analysis. In the case of melanoma, certain indicators can help detect it and distinguish it from other forms of skin cancer, not to mention that about a third of melanomas originate from moles we already have. The ABCDE (Asymmetry, Border, Color, Diameter, Evolution) method allows people to independently check their moles and detect any changes. Most melanomas are asymmetrical or have asymmetrical growth, have irregular borders, show different shades of color, and are larger in size. In addition, it is important to keep an eye on the evolution of moles: if changes in color or shape are observed, a referral to a specialist should be made. Last but not least, it is good to conduct periodic screenings, especially in the presence of the risk factors mentioned earlier.

Learn about UPMC's Dermatology Services and make an appointment with one of our specialists.