Basal cell carcinoma (BCC) is the most common type of skin cancer. It occurs more often in men than in women. The incidence of this skin cancer among Caucasians in the US is .19% per year, and the incidence is increasing worldwide. Most basal cell carcinoma is seen after the age of 40, but those seen in patients who are younger than 35 tend to be more aggressive.
What is Basal Cell Carcinoma?
Basal cell carcinoma arises in cells called basal keratinocytes in the deepest layer of the epidermis, hair follicles, and sweat ducts. UVB radiation is important for the induction of this skin cancer damaging DNA and its repair system, also causing mutations in tumor-suppressing genes. Basal cell carcinoma grows by direct extension and appears to rely on the surrounding supportive tissue to grow. Therefore, it does not metastasize through blood vessels or lymphatics. Its course is unpredictable. It may grow slowly for years, then suddenly grow rapidly.
Basal Cell Carcinoma Risk Factors
Some common risk factors for basal cell carcinoma include:
- Chronic sun exposure mainly to UVB radiation but also UVA
- A history of repeated sunburns or childhood exposure to the sun
- A suppressed immune system
- HIV disease
- Ionizing radiation used for acne in the 1940's
- Fair skin and the propensity to freckle or burn rather than tan
Some rare risk factors for basal cell carcinoma include:
- Exposure to arsenic
- A condition called granuloma inguinale
- Scarred or previously damaged skin, especially radiation damage
- Rare genetic diseases such as xeroderma pigmentosa, nevoid basal cell carcinoma syndrome, and albinism
Appearance of Basal Cell Carcinoma
The skin changes caused by this skin cancer depend on the type of basal cell carcinoma involved. The most common appearance is of a raised pink or pearly white bump that may have a translucent, rolled, pearly edge and small visible blood vessels. Some basal cell carcinomas are pigmented and may look like a mole with a pearly border. Another type is flat and scaly with a waxy appearance and an indistinct border. All of the basal cell carcinoma types have a tendency to bleed with minimal to no trauma. If the lesion has invaded the surrounding tissues, it may be fixated and difficult to move. 85% occur on the face and neck since these areas are the most exposed to the sun.
Pictures of Basal Cell Carcinoma
The following pictures show various basal cell carcinoma lesions:
- Basal cell carcinoma on the face
- Basal cell carcinoma on the nose
- Pigmented basal cell carcinoma
- Spreading basal cell carcinoma on the back
- Basal cell carcinoma behind the ear
Diagnosis of Basal Cell Carcinoma
The only way to diagnose basal cell carcinoma is to biopsy suspicious looking lesions. The preferred type of biopsy is called a shave biopsy in which the lesion is shaved off with a flexible razor. Depending on the extent of the skin cancer, another biopsy option is to excise the lesion. Useful information such as whether the complete tumor was removed and tumor depth can only be obtained by biopsy.
Find out more about how basal cell carcinoma is treated.