What Is Basal Cell Carcinoma? Symptoms, Causes, and Treatment
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer: What is basal cell carcinoma?
Basal cell carcinoma is a type of skin cancer that forms in the basal cells of the epidermis, often appearing as a small, shiny bump or scaly patch on sun-exposed skin. [1] It usually follows UV damage to DNA. [1] It is treated by removing the cancer through surgery, curettage, cryotherapy or laser. [1] The prognosis is excellent, and it very rarely spreads. [1]
Key Takeaways
Basal cell carcinoma is the most common type of cancer overall, with more than 4 million new US cases each year. [1]
It starts in the basal cells, which make new skin cells in the lower layer of your epidermis. [1]
The four main types are nodular, superficial spreading, sclerosing (morpheaform), and pigmented. [1]
UV exposure from the sun or tanning beds is the usual trigger behind the DNA change that causes it. [1]
Treatment removes the cancer, and the prognosis is excellent because it very rarely spreads. [1]
Daily sun protection and monthly self-checks are your best prevention tools. [1]
What the research says
Basal cell carcinoma is the most common human cancer worldwide, and cases keep rising. A continuing medical education review describes BCC as the most common human cancer worldwide, with incidence continuing to increase and a significant burden in illness and cost. (Cameron et al., J Am Acad Dermatol, 2019) [2]
Nicotinamide lowered new skin cancers in high-risk people, though the basal cell result alone was not statistically significant. In a randomized trial of 386 people who had at least two nonmelanoma skin cancers in the previous 5 years, 500 mg of nicotinamide twice daily for 12 months lowered the rate of new nonmelanoma skin cancers by 23% (95% CI 4 to 38) versus placebo. For basal cell carcinomas alone the rate was 20% lower (95% CI -6 to 39; P=0.12), and there was no evidence of benefit after nicotinamide was stopped. (Chen et al., N Engl J Med, 2015) [3]
What Is Basal Cell Carcinoma?
Basal cell carcinoma (BCC) is a type of skin cancer that causes a lump, bump, or lesion to form on the outside layer of your skin, called the epidermis. These growths develop on areas of your skin that receive a lot of sun exposure. With treatment to remove the cancer from your skin, the outlook is positive. [1]
What Are Basal Cells?
Basal cells are microscopic cells in the outer layer of your skin (the epidermis), which is the skin layer you can see and touch. These cells are responsible for making new skin cells by dividing and copying themselves. As basal cells create new cells, older skin cells push to the surface of the epidermis, where they die and leave your body. [1]
What Are the Types of Basal Cell Carcinoma?
There are four main types of basal cell carcinoma, and each has a different look and common location on the body. [1]
Type | What it looks like | Where it commonly appears |
Nodular | The most common type; a round pimple with visible blood vessels surrounding it (telangiectasias) [1] | Sun-exposed areas, especially the face |
Superficial spreading | Small, shallow marks that are slightly lighter in color than the surrounding skin [1] | Trunk (torso), arms, and legs [1] |
Sclerosing (morpheaform) | Lesions that look like scars that slowly expand over time; can also appear as a small red dot [1] | Most common on the face [1] |
Pigmented | A rare type that causes hyperpigmentation — an area of skin darker than the surrounding skin [1] | Sun-exposed areas |
Who Does Basal Cell Carcinoma Affect?
BCC can affect anyone. It occurs more often in people older than 50, and people with fair skin and light eyes are more likely to develop it. Anyone who has had BCC once is at higher risk of developing another nonmelanoma skin cancer in the future. [1]
How Common Is It?
Basal cell carcinoma is the most common type of cancer overall and the most common type of skin cancer. [1] [2] The number of new cases in the United States exceeds 4 million each year. [1]
What Are the Signs of Basal Cell Carcinoma?
The signs of basal cell carcinoma center on changes to your skin — lumps, bumps, pimples, scabs, or scaly lesions. The bump may be slightly see-through (translucent) and close to your normal skin color, or range from white to pink, brown to black, or black to blue. It may appear shinier than the surrounding skin with tiny visible blood vessels, grow slowly over time, and be itchy or painful. In some cases, the lump forms an ulcer that can ooze clear fluid or bleed with contact. [1]
Sign | What to look for |
Skin lumps and lesions | Lumps, bumps, pimples, scabs, or scaly lesions on your skin |
Color variation | Translucent, skin-colored, white to pink, brown to black, or black to blue |
Visible blood vessels | Shiny appearance with tiny blood vessels around the lump |
Slow growth | The lump grows slowly over time |
Sensations | The lump may be itchy or painful |
Ulceration | The lump may form an ulcer that oozes clear fluid or bleeds with contact |
Where Do Symptoms Appear?
Basal cell carcinomas most commonly appear on areas of your body exposed to the sun. The most common locations are the face, scalp, nose, eyelids, legs, ears, and arms. [1]
What Causes Basal Cell Carcinoma?
A change to your DNA causes basal cell carcinoma. This change usually happens after your skin has too much exposure to ultraviolet (UV) rays from sunlight or tanning beds. [1]
How Does the DNA Change Work?
Your genes give your body's DNA instructions to make new cells to replace cells that reach the end of their lifespan, by copying and replicating themselves. If a mutation affects one of your genes, your DNA no longer has the correct instructions for making new cells the way it should. [1]
Basal cells make new cells similar to how you turn on a light switch when you enter a room — and turn it off when you leave. When a genetic mutation targets your DNA, your basal cells can't turn off the switch when they "leave the room." The cells keep multiplying, which causes lumps (tumors) or lesions to form in the epidermis. [1]
Are There Genetic Causes?
Yes. A rare inherited condition called basal cell nevus syndrome (Gorlin syndrome) causes BCC to appear in childhood. [1]
How Is Basal Cell Carcinoma Diagnosed?
Depending on the appearance of the skin lesion, your provider might immediately suspect a basal cell carcinoma diagnosis. To confirm, your provider completes a physical exam and asks questions about your symptoms. [1]
Diagnostic question | What it reveals |
When did the lump or lesion appear? | How long the growth has been developing |
Did the lesion change in size? | Whether it is actively growing |
Does it look different than when you first noticed it? | Whether the appearance is evolving |
Is the lesion painful or itchy? | Whether symptoms are present |
Have you had skin cancer previously? | Your personal history and future risk |
What Tests Confirm the Diagnosis?
After the physical exam, your provider might order tests to confirm the diagnosis.
How Is the Stage Determined?
After the exam and test results, your provider determines the stage of the diagnosis using several qualifiers: the size of the lesion and whether it grew deeper into your tissues, any signs of cancer in your lymph nodes, whether the cancer spread (metastasized) to other parts of your body, and the size, shape, location, and growth speed of the lesion. [1]
How Is Basal Cell Carcinoma Treated?
Treatment removes the cancer from your body. Your provider chooses the best option by factoring in your overall health, age, the location of the cancer, and the size of the BCC. [1]
Treatment | How it works |
Electrodessication and curettage | Scraping off the cancerous lump with a curette, then burning with a special electric needle [1] |
Surgery | Removing the lump or lesion with a scalpel (excision or Mohs surgery) [1] |
Cryotherapy or cryosurgery | Freezing the cancerous lump to remove it [1] |
Chemotherapy | Using powerful medicines to kill cancerous cells [1] |
Photodynamic therapy (PDT) | Applying blue light and a light-sensitive agent to your skin [1] |
Laser therapy | Using high-energy laser beams to remove cancer instead of a scalpel [1] |
What Happens If It's Left Untreated?
If basal cell carcinoma goes untreated, the skin cancer can slowly grow in size and invade deeper tissues like muscle, bone, and cartilage. It may become painful and ulcerated, which can cause bleeding and infection. In extremely rare cases, BCC can spread to other parts of the body and cause life-threatening side effects. [1]
Are There Medications for Advanced Cases?
Although rare, if BCC becomes locally advanced or spreads (metastasizes) to another location, the FDA has approved two medicines for people who aren't good candidates for surgery or radiation therapy. [1]
If you take either medication, you must not get pregnant while on therapy and for several months after completing it. Any surgical removal will also leave a scar, with a low risk of bleeding or infection. [1]
What Can I Expect After Treatment?
The prognosis for people diagnosed with basal cell carcinoma is excellent. BCC rarely spreads to other areas of your body and causes harm. [1]
There is a low chance that BCC returns after removal. If you notice a new lesion around the scar from previous treatment, visit your provider immediately. [1]
How Can Basal Cell Carcinoma Be Prevented?
While not all cases can be prevented, you can take steps to reduce your risk.
Prevention step | Details |
Avoid peak sun hours | Limit sun exposure from 10 a.m. to 4 p.m. [1] |
Skip tanning beds | Avoid indoor tanning entirely [1] |
Use daily sunscreen | SPF 30 or higher each day; reapply every two hours when outdoors or swimming [1] |
Wear protective clothing | UPF clothing, broad-brimmed hats, and sunglasses [1] |
Monthly self-exam | Check your skin once per month for unusual lumps or lesions [1] |
Annual skin exam | Visit a dermatologist once a year for a professional skin examination [1] |
Consider a supplement | Nicotinamide (vitamin B3) 500 milligrams twice a day can reduce the risk of new BCC and squamous cell carcinoma [1] |
Ask questions | Contact your provider with any questions or changes in your skin |
When Should I See My Provider?
It's important to contact a provider any time you have a skin problem that doesn't resolve on its own. If you develop any new marks on your skin, if a mole gets larger, or if you experience pain or itchiness associated with a lump or lesion, contact a provider right away. [1]
What Questions Should I Ask My Doctor?
Question | Why it matters |
What stage is my diagnosis? | Guides treatment decisions |
Did cancer spread to other parts of my body? | Determines whether imaging is needed |
Do I need to see a dermatologist? | Ensures specialist care |
Are there side effects to the treatment you recommend? | Helps you weigh the options |
How Does BCC Compare to Other Skin Cancers?
Basal cell carcinoma is one of several skin cancers. For comparison, see our guides to squamous cell carcinoma of the skin and melanoma.
Cancer type | How it differs |
Squamous cell carcinoma (SCC) | The second most common type of skin cancer after BCC; caused by overproduction of squamous cells; most common on sun-exposed skin of the head and neck, trunk, and extremities [1] |
Melanoma | Starts in melanocytes, the cells that give your skin pigment; less common than BCC or SCC, but may spread quickly throughout your body if not caught early and treated [1] |
A precancer, such as actinic keratosis, is a benign (non-cancerous) growth of cells in your epidermis caused by long-term sun exposure. It is most commonly seen on the sun-exposed skin of your head and neck — including the tops of your ears and lips — as well as your arms and legs. While benign on its own, it can develop into skin cancer, specifically squamous cell carcinoma. [1]
Conclusion
Basal cell carcinoma is the most common type of cancer in the world, but it is also one of the most manageable. Because it grows slowly, rarely spreads, and responds well to removal treatments, finding it early makes all the difference. Know your skin: do a monthly self-check, protect yourself from UV exposure every day, and get any new lump, bump, or changing spot examined promptly. If you'd like to share this information visually, Rinnit's infographic templates can help you turn health content like this into clear, beautiful graphics.
Frequently Asked Questions
Is basal cell carcinoma the most common type of cancer?
Yes. Basal cell carcinoma is the most common type of cancer overall and the most common type of skin cancer, with more than 4 million new cases in the United States each year. [1]
Is basal cell carcinoma dangerous?
In most cases, no. BCC rarely spreads to other parts of the body and causes harm, and the prognosis after treatment is excellent. Untreated, it can invade deeper tissues like muscle, bone, and cartilage, and in extremely rare cases it can spread and become life-threatening. [1]
What does basal cell carcinoma look like?
It typically appears as a small, sometimes shiny bump or scaly flat patch on sun-exposed skin. The lump may be translucent, skin-colored, white to pink, brown to black, or black to blue, and may have tiny visible blood vessels around it. [1]
What causes basal cell carcinoma?
A change to your DNA causes BCC, and this change usually happens after your skin has too much UV exposure from sunlight or tanning beds. A rare inherited condition called basal cell nevus syndrome (Gorlin syndrome) can cause it in childhood. [1]
Who is at risk for basal cell carcinoma?
Anyone can develop BCC, but it occurs more often in people older than 50 and in people with fair skin and light eyes. Previous BCC also raises your risk of another nonmelanoma skin cancer. [1]
Is basal cell carcinoma curable?
Yes. Treatment removes the cancer from your body through methods like surgery, electrodessication and curettage, cryotherapy, photodynamic therapy, or laser therapy. The prognosis is excellent, with a low chance of the cancer returning after removal. [1]
Does basal cell carcinoma spread?
It is extremely rare for BCC to spread. If your provider suspects it has, they may order an MRI or CT scan to check the lymph nodes or internal organs. [1]
Can I take anything to lower my risk?
Taking nicotinamide (vitamin B3) 500 milligrams twice a day can reduce the risk of developing new basal cell and squamous cell carcinomas, alongside daily SPF 30+ sunscreen and monthly skin self-exams. [1]
What is the difference between nodular and superficial BCC?
Nodular BCC, the most common type, looks like a round pimple with visible blood vessels around it. Superficial spreading BCC causes small, shallow marks that are slightly lighter in color than the surrounding skin, typically on the torso, arms, and legs. [1]
Is basal cell carcinoma the same as melanoma?
No. BCC starts in the basal cells of the epidermis and rarely spreads. Melanoma starts in melanocytes, the pigment-producing cells, and while less common, can spread quickly through the body if not caught early and treated. [1]
Can a basal cell carcinoma come back after treatment?
There's a low chance that BCC returns after removal. If you notice a new lesion around the scar from previous treatment, visit your provider immediately. [1]
How do I know if a bump is basal cell carcinoma?
Look for a lump that is shiny, slowly growing, translucent or pearly, has tiny visible blood vessels, forms a scab or ulcer that bleeds or oozes, or is itchy or painful. Any skin problem that doesn't resolve on its own should be examined by a provider.
Related Reading
Electrosurgery: Types, Uses and Risks explains electrosurgery.
Photodynamic Therapy (PDT): Uses, Procedure, Recovery and Risks explains how a light-activated drug treats precancer and some skin cancers, with recovery and light-safety tips.
Learn more in our guide to Skin Biopsy: Types, What to Expect, Results and Aftercare.
Skin Self-Exam: How to Check Your Skin and the ABCDEs of Melanoma explains how to check your own skin monthly using the ABCDEs of melanoma.
References
Cleveland Clinic. Basal Cell Carcinoma. Cleveland Clinic. Last updated August 31, 2022. https://my.clevelandclinic.org/health/diseases/4581-basal-cell-carcinoma
Cameron MC, Lee E, Hibler BP, et al. Basal cell carcinoma: epidemiology; pathophysiology; clinical and histological subtypes; and disease associations. J Am Acad Dermatol. 2019;80(2):303-317. PMID 29782900. https://doi.org/10.1016/j.jaad.2018.03.060
Chen AC, Martin AJ, Choy B, et al. A phase 3 randomized trial of nicotinamide for skin-cancer chemoprevention. N Engl J Med. 2015;373(17):1618-1626. PMID 26488693. https://doi.org/10.1056/NEJMoa1506197
Medical disclaimer
This article is for informational purposes only and is not medical advice. Always consult a qualified healthcare provider for diagnosis and treatment decisions.
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