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Basal Cell Carcinoma
If you have a basal cell carcinoma or are close to someone who does, knowing what to expect can help. Here you can find out all about this cancer, including risk factors, symptoms, how it is found, and how it is treated.
About basal cell carcinoma
Basal cell carcinoma (BCC), also called basal cell skin cancer or basal cell cancer, is the most common type of skin cancer. About 8 out of 10 skin cancers are basal cell carcinomas.
BCCs start in the basal cell layer of the skin, usually on sun-exposed areas, especially the face, head, neck, and arms.
These cancers tend to grow slowly. But they are left untreated, it can grow into nearby areas and invade the bones or other tissues beneath the skin. It’s rare for BCC to spread to other parts of the body.
If not removed completely, BCC can come back (recur) in the same place on the skin. People who have had basal cell skin cancers are also more likely to get new ones in other areas of the skin.
Understanding the skin
The skin is an organ that has several layers and is made up of several types of cells.
Epidermis
Most skin cancers start in the top layer of skin, called the epidermis. There are 3 main types of cells in this layer.
Squamous cells are flat cells in the upper (outer) part of the epidermis, which are constantly shed as new ones form. When these cells grow out of control, they can develop into squamous cell skin cancer, also called squamous cell carcinoma (SCC).
Basal cells are in the lower part of the epidermis, called the basal cell layer. These cells constantly divide to form new cells to replace the squamous cells that wear off the skin’s surface. As these cells move up in the epidermis, they get flatter, eventually becoming squamous cells. Basal cell carcinomas (BCCs) are cancers that start in the basal cell layer.
Melanocytes make the brown pigment called melanin, which gives the skin its tan or brown color. Melanin acts as the body’s natural sunscreen, protecting the deeper layers of the skin from some of the harmful effects of the sun. Melanoma skin cancer starts in these cells.
Other skin layers
The basement membrane is a thin layer of tissue below the epidermis.
Two layers of skin called the dermis and the subcutis lie below the basement membrane. When a skin cancer becomes more advanced, it grows through the basement membrane and into these layers.
Other types of skin cancer
Aside from BCC, there are several other types of skin cancer.
About 2 out of 10 skin cancers are squamous cell carcinomas (SCCs). They are also called squamous cell skin cancers, cutaneous squamous cell cancers, or squamous cell cancers. These cancers start in the flat cells in the upper part of the epidermis.
SCCs commonly appear on sun-exposed areas of the body such as the face, ears, neck, lips, arms, and backs of the hands. They can also develop in scars or chronic skin sores elsewhere. Less often, they form in the skin of the genital area.
Learn more in Squamous Cell Carcinoma of the Skin.
These cancers develop from melanocytes, the pigment-making cells in the epidermis. Melanomas are much less common than basal and squamous cell cancers, but they are more likely to grow and spread if left untreated.
Learn more in Melanoma Skin Cancer.
Other types of skin cancer are much less common and are treated differently. These include:
- Merkel cell skin cancer
- Kaposi sarcoma
- Skin lymphoma
- Skin adnexal tumors – tumors that start in hair follicles or skin glands
- Various types of sarcomas
Together, these cancer types account for less than 1% of all skin cancers.
Benign skin tumors
Most skin tumors are benign (not cancerous) and rarely, if ever, turn into cancer. There are many kinds of benign skin tumors, including:
- Most types of moles
- Actinic keratoses (AKs), which are small, rough, or scaly spots on the skin that often appear on sun-exposed areas. If not treated, some AKs might progress to SCC over time.
- Seborrheic keratoses, which are tan, brown, or black raised spots with a waxy texture, or occasionally a whitish, slightly rough and crumbly surface when they are on the legs (also known as stucco keratosis)
- Hemangiomas, which are benign blood vessel growths often called strawberry spots
- Lipomas, which are soft tumors made up of fat cells
- Warts, which are rough-surfaced growths caused by some types of human papillomavirus (HPV)
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- References
Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).
Christensen SR, Wilson LD, Leffell DJ. Chapter 90: Cancer of the Skin. In: DeVita VT, Lawrence TS, Rosenberg SA, eds. DeVita, Hellman, and Rosenberg’s Cancer: Principles and Practice of Oncology. 11th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2019.
National Cancer Institute. Skin Cancer Treatment (PDQ®)–Health Professional Version. 2025. Accessed at https://www.cancer.gov/types/skin/hp/skin-treatment-pdq on June 1, 2026.
Wu PA. Basal cell carcinoma: Epidemiology, pathogenesis, clinical features, and diagnosis. UpToDate. 2026. Accessed at https://www.uptodate.com/contents/basal-cell-carcinoma-epidemiology-pathogenesis-clinical-features-and-diagnosis on June 1, 2026.
Xu YG, Aylward JL, Swanson AM, et al. Chapter 67: Nonmelanoma Skin Cancers. In: Niederhuber JE, Armitage JO, Doroshow JH, Kastan MB, Tepper JE, eds. Abeloff’s Clinical Oncology. 6th ed. Philadelphia, Pa: Elsevier; 2020.
Last Revised: August 11, 2026
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