Nonmelanoma Skin Cancer: Introduction

What is nonmelanoma skin cancer?

Cancer starts when cells in the body change and grow out of control. The abnormal cells may form a lump or mass, called a tumor. Some cells may spread into nearby tissues or other parts of the body. This is called metastasis.

Nonmelanoma is the most common type of skin cancer. It is successfully treated if found early. It is not the same as melanoma. Melanoma is a serious and fast-growing type of cancer. It starts in the pigment cells of the skin and may spread to other parts of the body.

Understanding the skin

The skin is the largest organ of the body. It protects us from heat, sunlight, injury, and infection. It stores water and fat, and makes vitamin D. The skin has 3 layers:

• The outer layer called the epidermis

• The middle layer called the dermis

• The inner, deep layer called the hypodermis (or subcutaneous tissue)

The epidermis has multiple layers. It has 2 types of cells: keratinocytes and melanocytes. Keratinocytes are the most common type. They are divided into basal cells and squamous cells. Basal cells are small, round cells in the inner basal layer of the epidermis. They divide to replace lost skin cells. Squamous cells are in the outer layer of the epidermis. These thin, flat cells are always shedding as new ones form.

What are the different types of nonmelanoma skin cancer?

Basal cell carcinoma

This is the most common type of skin cancer. It starts in abnormal keratinocytes in the basal layer of the epidermis. It grows slowly and rarely spreads to other parts of the body. Having basal cell carcinoma puts you at higher risk for other types of skin cancer.

• Where is it found? Skin that is exposed to the sun. This includes the face, ears, head, neck, arms, and hands. But it can start on any patch of skin.

• What does it look like?

  • Pinkish, small, raised, shiny, or pearly bumps

  • Crusty, itchy, scaly patches

  • Flat white or yellow spots

  • Crusty, bleeding, nonhealing open sores

Treatment helps prevent this cancer from growing deeper into tissues under the skin, including bone, which can cause serious damage. Sometimes, basal cell carcinoma comes back after treatment. But nearly all cases can be cured, and for most people it is not life-threatening.

Squamous cell carcinoma

This is the second most common type of skin cancer. It starts in abnormal keratinocytes in the squamous layer of the epidermis.

• Where is it found? Skin that is exposed to the sun. This includes the face, ears, head, neck, arms, and hands. It can also grow on genital skin, in scars, and in skin sores that don’t go away.

• What does it look like? Red, firm bumps or flat, rough, scaly, crusty, wart-like growths

Squamous cell carcinoma tends to grow quickly. But it rarely spreads to other parts of the body. Most cases are found early enough to be treated and cured.

Merkel cell carcinoma

This is a very rare type of skin cancer that grows fast. It starts deep in the epidermis. Merkel cells are very close to nerve endings. They help your skin sense light touch.

• Where is it found? Skin that is exposed to the sun. This includes the face, ears, head, neck, arms, and hands. But it can start on any patch of skin.

• What does it look like? A single firm, raised shiny lump that doesn't hurt. The lump may be red, pink, purple, or blue.

A Merkel cell cancer tumor tends to grow very fast and spread (metastasize). The sooner it is found, the easier it is to treat before it can spread.

Cutaneous lymphoma

This is also known as lymphoma of the skin. It’s a type of non-Hodgkin lymphoma. (NHL). NHL is a cancer that starts in white blood cells called lymphocytes. These white blood cells are part of your immune system. They normally fight infections.

• Where is it found? It can start on any patch of skin on the body.

• What does it look like? Itchy, scaly patches or rash, or red, purple or brown bumps

Cutaneous lymphoma can develop over many years. There are several subtypes. These are based on what kind of white blood cell the cancer starts in, how the cancer cells look, and proteins found on the cancer cells.

Kaposi sarcoma

This cancer starts in the cells that line lymph or blood vessels. There are 4 main types of Kaposi sarcoma, but the cancer cells look almost the same in all of them.

• Where is it found? It can grow on skin on the legs, feet, face, and genitals. It can grow in the mucous membranes of the mouth, nose, and throat. And it can grow on internal organs.

• What does it look like? Purple, brown, or red patches

Talk with your healthcare provider

It’s normal to feel uncertain about what comes next. If you have questions about nonmelanoma skin cancer, reach out to your healthcare provider. They are here to help you understand more about your diagnosis and work with you every step of the way.