After discovering evidence of cancer, a physician’s next step will be determining the specific type. Correctly identifying the type of cancer that a patient has is critical, since this information will affect their prognosis and treatment options. There are numerous types and subtypes of nonmelanoma skin cancer, which are outlined below.
Common types of nonmelanoma skin cancer
The two most common types of nonmelanoma skin cancer are basal cell carcinoma and squamous cell carcinoma.
Basal cell carcinoma
Basal cell carcinoma is the most common type of skin cancer, with approximately 3.6 million cases diagnosed in the United States each year. As its name suggests, this malignancy originates in the basal cells, which are located at the bottom of the outermost layer of skin (the epidermis). These cells are responsible for producing new skin cells, which replace the older skin cells as they die.
Researchers agree that long-term ultraviolet (UV) radiation exposure can cause basal cell carcinoma to develop, so it commonly occurs in places that have been regularly exposed to the sun (such as the face and neck). Fortunately, basal cell carcinoma rarely spreads (metastasizes) to other areas of the body.
Squamous cell carcinoma
Each year, approximately 1.8 million cases of squamous cell carcinoma are diagnosed. It develops in the squamous cells, which line the outer layer of the epidermis, the body’s hollow organs and the respiratory and digestive tracts.
Like basal cell carcinoma, squamous cell carcinoma usually appears on areas of the body that have been exposed to the sun. However, squamous cell carcinoma can also develop on the lips, mucous membranes (like the skin that lines the mouth or nose) and parts of the body where patients have experienced chronic inflammatory skin conditions. Although squamous cell carcinoma is more likely than basal carcinoma to spread or metastasize to distant areas of the body, it’s still relatively rare for it to do so.
Less common types of nonmelanoma skin cancer
Although basal cell carcinoma and squamous cell carcinoma make up the large majority of nonmelanoma skin cancer cases, there are various other rare forms of this malignancy that together comprise a small percentage of the total number of diagnoses.
Merkel cell carcinoma
Merkel cell carcinoma develops in the hormone-producing cells of the skin and hair follicles. It gets its name due to its resemblance to normal Merkel cells of the skin under a microscope. This skin cancer can appear as a firm lesion on the skin. These lesions can appear in various sizes and are typically red, blue or skin-colored.
The word “cutaneous” simply refers to the skin. Some of the body’s lymphocytes (immune cells) are found in the skin, so when the cancer originates there, it is called cutaneous lymphoma. Depending on the type of lymphocytes affected (B cells or T cells), this type of skin cancer may be classified as cutaneous B-cell lymphoma or cutaneous T-cell lymphoma. The skin lesion often looks red and scaly, similar to eczema.
Skin adnexal neoplasm
These tumors originate in the hair follicles or skin glands. Most often, these tumors are benign, although it is possible for them to be malignant and to spread or metastasize.
Sarcomas, in general, are rare tumors that can occur in almost any soft tissues of the body, including the skin. Only 13,000 soft-tissue sarcoma cases occur in the United States each year, and the majority of those cases develop in the extremities, the chest region (thorax) and the midsection.
When sarcomas develop in the skin, they’re referred to as cutaneous sarcomas or skin sarcomas. These sarcomas of the skin often appear as a lump under the skin and are usually painless. Cutaneous sarcomas represent only a small portion of soft-tissue sarcomas, and subtypes include angiosarcoma, dermatofibrosarcoma protuberans, Kaposi’s sarcoma and cutaneous leiomyosarcoma.
Like other forms of soft-tissue sarcoma, cancerous (malignant) skin sarcomas are often treated by surgically excising them. It’s relatively common for skin cancer sarcomas to recur in the area in which they originally developed, but it’s rare for them to spread to distant areas of the body.
As was noted above, dermatofibrosarcoma protuberans (DFSP) is a subtype of cutaneous sarcoma skin cancer. DFSP cancer is a rare type of sarcoma that develops in the deep layers of the skin. While DFSP is most commonly found on the torso, it can also be found on the arms, head, neck or legs. It usually looks like a flat or slightly raised skin patch that feels rubbery or hard, and is typically violet, reddish brown or skin colored. As DFSP progresses, it may cause lumps of tissue (protuberans) to form near the skin’s surface.
When compared to various other malignancies, DFSP is slow-growing and rarely spreads beyond the skin. In fact, less than 5% of patients experience metastasis. As such, the dermatofibrosarcoma protuberans survival rate is very high. As with other types of skin sarcomas, DFSP is usually treated with surgery to remove the cancer.
Skin cancer diagnosis and treatment at Moffitt
The Cutaneous Oncology Program at Moffitt Cancer Center offers multispecialty treatment for all types of skin cancer in one convenient location. No matter what point you are at in your journey, you will be welcome here at Moffitt. A referral is not required to schedule an appointment. Call us today at 1-888-663-3488, or complete a new patient registration form. We’ve disrupted the traditional patient care model in order to start necessary treatment as early as possible, so you can expect to be connected with a cancer expert in just one day.
National Cancer Institute: Squamous Cell Carcinoma
National Library of Medicine: Dermatofibrosarcoma Protuberans
National Library of Medicine: Advances in the Systemic Treatment of Cutaneous Sarcomas
Skin Cancer Foundation: Basal Cell Carcinoma Overview