Table of ContentsView AllTable of ContentsHow Each LooksAK Progression to BCCSun ExposureTreatment DifferencesRisks of Untreated Symptoms
Table of ContentsView All
View All
Table of Contents
How Each Looks
AK Progression to BCC
Sun Exposure
Treatment Differences
Risks of Untreated Symptoms
Basal cell carcinomais the most common form of nonmelanoma skin cancer. In contrast,actinic keratosisis a precancerous condition that sometimes turns into skin cancer.
If you have actinic (solar) keratosis (AK) lesions, you are at a heightened risk for two types of skin cancer: basal cell carcinoma (BCC) andsquamous cell carcinoma.Actinic keratosis is more likely to progress into squamous cell carcinoma (SCC) than BCC.
This article will discuss the differences in appearance between actinic keratosis and basal cell carcinoma. It will also detail the causes and treatments for both conditions.
This photo contains content that some people may find graphic or disturbing.See PhotoActinic keratosis on ear and basal cell carcinoma under eye.Reproduced with permission from © DermNetdermnetnz.org2023
This photo contains content that some people may find graphic or disturbing.See Photo
This photo contains content that some people may find graphic or disturbing.
Reproduced with permission from © DermNetdermnetnz.org2023
How Actinic Keratosis and Basal Cell Carcinoma Look
Basal cell carcinomas have been known to be misdiagnosed as AK lesions, though this is rare.In general, these conditions don’t resemble each other physically.
AKand BCCmay have the following characteristics:
Actinic KeratosisSmall sizeScaly, rough, or crusty textureRed, tan, white, pink, or flesh-toned in color. In some instances, several colors may appear within one patchCan be raised or flatMay feel dry to the touchBasal Cell CarcinomaOpen sores that don’t heal for weeks or months, or that reemerge after healing; may bleed, ooze, or crustRed, irritated patches of skin that are painful or itchySmall, shiny bumps that vary in color, including being tan, brown, or black in dark-skinned people or pink, red, white, or clear in light-skinned peopleTiny pink growths with raised, rolled edges and crusted, indented centers that may have visible surface blood vesselsScar-like areas of skin that have poorly defined borders that may look shiny or waxy
Actinic KeratosisSmall sizeScaly, rough, or crusty textureRed, tan, white, pink, or flesh-toned in color. In some instances, several colors may appear within one patchCan be raised or flatMay feel dry to the touch
Small size
Scaly, rough, or crusty texture
Red, tan, white, pink, or flesh-toned in color. In some instances, several colors may appear within one patch
Can be raised or flat
May feel dry to the touch
Basal Cell CarcinomaOpen sores that don’t heal for weeks or months, or that reemerge after healing; may bleed, ooze, or crustRed, irritated patches of skin that are painful or itchySmall, shiny bumps that vary in color, including being tan, brown, or black in dark-skinned people or pink, red, white, or clear in light-skinned peopleTiny pink growths with raised, rolled edges and crusted, indented centers that may have visible surface blood vesselsScar-like areas of skin that have poorly defined borders that may look shiny or waxy
Open sores that don’t heal for weeks or months, or that reemerge after healing; may bleed, ooze, or crust
Red, irritated patches of skin that are painful or itchy
Small, shiny bumps that vary in color, including being tan, brown, or black in dark-skinned people or pink, red, white, or clear in light-skinned people
Tiny pink growths with raised, rolled edges and crusted, indented centers that may have visible surface blood vessels
Scar-like areas of skin that have poorly defined borders that may look shiny or waxy
Positive Pathology Findings
Basal cell carcinoma and actinic keratosis are definitively diagnosed through abiopsy(removing a sample tissue for examination in the lab). These conditions do not resemble each other under a microscope.
To get a skin sample to biopsy, part or all of the suspicious lesion will be removed for laboratory analysis. If you have multiple lesions, samples may be taken from some or all.
Apathologistwill analyze the skin samples under a microscope, to check for evidence of cancer. If cancer cells are found, these findings are said to be positive for cancer.
The pathologist will also use the skin samples to determine if you have a different diagnosis, rather than skin cancer or AK. Conditions that mimic skin cancer includebenign moles (nevus)andpsoriasis.
Differences and Similarties Between BCC and SCC
Basal cell carcinomas and squamous cell carcinoma most commonly affect areas of unprotected skin that have been exposed consistently to sunlight.
Around 75% to 80% of nonmelanoma skin cancer is basal cell carcinoma.These skin cancers start in basal cells located in the outermost layer of the skin.
Around 20% of nonmelanoma skin cancer is squamous cell carcinoma.These skin cancers start in squamous cells located in the outer or middle layers of the skin.
Actinic Keratosis Progressing to Basal Cell Carcinoma
Not every AK lesion becomes cancerous. Around 1% to 10% of AK progresses to SCC.Actinic keratosis may also transform into basal cell carcinoma, but this is less common.
The transformation of actinic keratosis into squamous cell carcinoma is thought to be faster than the progression of AK into basal cell carcinoma.Both transformations may take up to two years.
Sun Exposure: Actinic Keratosis vs. Basal Cell Carcinoma
Long-term sun exposure of unprotected skin is the main risk factor for basal cell carcinoma and actinic keratosis.That’s why these lesions typically manifest on the face and on areas of the body that get the most sun.
If you don’t protect your skin with sunscreen containing a high sun protection factor (SPF), clothing, or hats, you may be putting yourself at risk for all types of skin cancer, includingmalignant melanoma, the deadliest form. Outdoor workers, exercisers, and sunbathers are all vulnerable populations.
Since damage from the sun’s ultraviolet (UV) rays is cumulative, older adults are at a heightened risk. However, anyone of any age can get skin cancer.
Other Causes
In addition to the sun, exposure to UV radiation from human-made sources can put you at risk for precancers and cancers of the skin. These include:
Additional Risk Factors
Anyone can get skin cancer. However, certain risk factors may make you more vulnerable:
The treatment options for these conditions have some overlap but may vary. When your treatment plan is being determined, several factors will be considered, including your personal preferences, age, and general health.
The size, location, and number of lesions you have will also be a factor. In general, BCC is treated more aggressively than AK, especially if it has spread.
Precancerous Actinic Keratosis
It’s not possible to predict which AK lesions will become cancerous and which won’t, so destroying or removing the lesion or lesions is typically recommended. You may also wish to have AK lesions removed for cosmetic reasons, or to eliminate symptoms, like itching or pain.
Some AK treatments may be done in one or two sessions at a dermatologist’s office. They include:
If you have many AK lesions or lesions that can be felt but not seen, your dermatologist may recommend at-home treatment instead of an in-office procedure. You will apply topical medication for several weeks or longer. Medications used for this purpose include:
Cancerous Basal Cell Carcinoma
Several treatments are used to eradicate BCC tumors. Surgical removal is often recommended. The surgical procedures most commonly used for BCC are:
Other treatments may be recommended if you aren’t a candidate for surgery or have very superficial BCC lesions. They include:
AK may progress into squamous cell carcinoma or basal cell carcinoma. When left untreated, these skin cancers can cause disfigurement, as well as discomfort. SCC can also, in some instances, become deadly.
Always have a specialist, like a dermatologist, assess any lesions you have on your skin. They can best determine if treatment is needed and, if so, which kind makes sense for you.
Summary
Actinic keratosis is a precancerous condition that sometimes progresses into skin cancer. It is most likely to transform into squamous cell carcinoma. It may also transform into basal cell carcinoma.
AK lesions do not typically resemble basal cell carcinoma visually or under a microscope. A dermatologist can diagnose both conditions and guide you towards the best treatment option.
12 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Guorgis G, Anderson C, Lyth J, Falk M.Actinic keratosis diagnosis and increased risk of developing skin cancer: a 10-year cohort study of 17,651 patients in Sweden. Acta Derm Venerol. 2020;100(8):adv00128-6. doi:10.2340/00015555-3486Hwang SM, Pan HC, Hwang MK, Kim MW, Lee JS.Malignant skin tumor misdiagnosed as a benign skin lesion.Arch Craniofac Surg. 2016;17(2):86-89. doi:10.7181/acfs.2016.17.2.86American Academy of Dermatology.Actinic keratosis: signs and symptoms.Skin Cancer Foundation.Basal cell carcinoma warning signs.Canadian Cancer Society.Non-melanoma types of skin cancer.Majidian M, Anderson J, Rock J, et al.Non-invasive diagnosis of sun damaged skin: actinic keratosis vs squamous cell carcinoma. JDD. 2023;22(5):440-444. doi:10.36849/JDD.7097Siegal JA, Walker JL, Sachar M, et al.Actinic keratoses progress more quickly to squamous cell carcinoma than basal cell carcinoma.Dermatology Online Journal. 2016;22(9). doi:10.5070/D3229032516Centers for Disease Control and Prevention.Skin cancer risk factors.American Cancer Society.UV (ultraviolet) radiation and cancer risk.American Academy of Dermatology.Actinic keratosis: diagnosis and treatment.American Cancer Society.Treating basal cell carcinoma.Skin Cancer Foundation.Squamous cell carcinoma overview.
12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Guorgis G, Anderson C, Lyth J, Falk M.Actinic keratosis diagnosis and increased risk of developing skin cancer: a 10-year cohort study of 17,651 patients in Sweden. Acta Derm Venerol. 2020;100(8):adv00128-6. doi:10.2340/00015555-3486Hwang SM, Pan HC, Hwang MK, Kim MW, Lee JS.Malignant skin tumor misdiagnosed as a benign skin lesion.Arch Craniofac Surg. 2016;17(2):86-89. doi:10.7181/acfs.2016.17.2.86American Academy of Dermatology.Actinic keratosis: signs and symptoms.Skin Cancer Foundation.Basal cell carcinoma warning signs.Canadian Cancer Society.Non-melanoma types of skin cancer.Majidian M, Anderson J, Rock J, et al.Non-invasive diagnosis of sun damaged skin: actinic keratosis vs squamous cell carcinoma. JDD. 2023;22(5):440-444. doi:10.36849/JDD.7097Siegal JA, Walker JL, Sachar M, et al.Actinic keratoses progress more quickly to squamous cell carcinoma than basal cell carcinoma.Dermatology Online Journal. 2016;22(9). doi:10.5070/D3229032516Centers for Disease Control and Prevention.Skin cancer risk factors.American Cancer Society.UV (ultraviolet) radiation and cancer risk.American Academy of Dermatology.Actinic keratosis: diagnosis and treatment.American Cancer Society.Treating basal cell carcinoma.Skin Cancer Foundation.Squamous cell carcinoma overview.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Guorgis G, Anderson C, Lyth J, Falk M.Actinic keratosis diagnosis and increased risk of developing skin cancer: a 10-year cohort study of 17,651 patients in Sweden. Acta Derm Venerol. 2020;100(8):adv00128-6. doi:10.2340/00015555-3486Hwang SM, Pan HC, Hwang MK, Kim MW, Lee JS.Malignant skin tumor misdiagnosed as a benign skin lesion.Arch Craniofac Surg. 2016;17(2):86-89. doi:10.7181/acfs.2016.17.2.86American Academy of Dermatology.Actinic keratosis: signs and symptoms.Skin Cancer Foundation.Basal cell carcinoma warning signs.Canadian Cancer Society.Non-melanoma types of skin cancer.Majidian M, Anderson J, Rock J, et al.Non-invasive diagnosis of sun damaged skin: actinic keratosis vs squamous cell carcinoma. JDD. 2023;22(5):440-444. doi:10.36849/JDD.7097Siegal JA, Walker JL, Sachar M, et al.Actinic keratoses progress more quickly to squamous cell carcinoma than basal cell carcinoma.Dermatology Online Journal. 2016;22(9). doi:10.5070/D3229032516Centers for Disease Control and Prevention.Skin cancer risk factors.American Cancer Society.UV (ultraviolet) radiation and cancer risk.American Academy of Dermatology.Actinic keratosis: diagnosis and treatment.American Cancer Society.Treating basal cell carcinoma.Skin Cancer Foundation.Squamous cell carcinoma overview.
Guorgis G, Anderson C, Lyth J, Falk M.Actinic keratosis diagnosis and increased risk of developing skin cancer: a 10-year cohort study of 17,651 patients in Sweden. Acta Derm Venerol. 2020;100(8):adv00128-6. doi:10.2340/00015555-3486
Hwang SM, Pan HC, Hwang MK, Kim MW, Lee JS.Malignant skin tumor misdiagnosed as a benign skin lesion.Arch Craniofac Surg. 2016;17(2):86-89. doi:10.7181/acfs.2016.17.2.86
American Academy of Dermatology.Actinic keratosis: signs and symptoms.
Skin Cancer Foundation.Basal cell carcinoma warning signs.
Canadian Cancer Society.Non-melanoma types of skin cancer.
Majidian M, Anderson J, Rock J, et al.Non-invasive diagnosis of sun damaged skin: actinic keratosis vs squamous cell carcinoma. JDD. 2023;22(5):440-444. doi:10.36849/JDD.7097
Siegal JA, Walker JL, Sachar M, et al.Actinic keratoses progress more quickly to squamous cell carcinoma than basal cell carcinoma.Dermatology Online Journal. 2016;22(9). doi:10.5070/D3229032516
Centers for Disease Control and Prevention.Skin cancer risk factors.
American Cancer Society.UV (ultraviolet) radiation and cancer risk.
American Academy of Dermatology.Actinic keratosis: diagnosis and treatment.
American Cancer Society.Treating basal cell carcinoma.
Skin Cancer Foundation.Squamous cell carcinoma overview.
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