basal cell carcinoma
Meaning of basal cell carcinoma: Common, local and slow: this skin cancer damages the tissue around it far more often than it travels anywhere else.
Definition of basal cell carcinoma
Basal cell carcinoma is a skin cancer that begins in the basal cells of the deepest layer of the epidermis, the outer sheet of skin. It usually appears on areas that collect years of sun exposure, such as the face, ears, scalp and neck, and it grows slowly in place rather than appearing suddenly. It is the most common form of skin cancer.
What does it look like?
The classic form is a small pearly or flesh-colored bump with a slightly translucent surface and fine blood vessels visible across it. As it enlarges the center may sink into a shallow crater with a rolled, raised border. Many are noticed because they bleed after a minor knock, scab over, and then break down again instead of healing. Growth is measured in months to years, so a lesion that has changed very little over a long period is not thereby reassuring.
Not every one looks like that. A superficial type appears as a flat pink scaly patch that is easily mistaken for eczema, and a sclerosing or morpheaform type looks like a pale waxy scar with no clear edge, which is why its true extent is often wider than it appears.
How does it behave next to the other skin cancers?
| Cancer | Cell of origin | Typical behavior |
|---|---|---|
| Basal cell carcinoma | Basal cells at the base of the epidermis | Grows locally; spread to distant organs is rare |
| Squamous cell carcinoma | Keratinocytes higher in the epidermis | Grows locally and can spread to lymph nodes, though uncommonly |
| Melanoma | Melanocytes, the pigment-making cells | Far fewer cases, but spreads readily and accounts for most skin cancer deaths |
Because it rarely reaches distant organs, the harm it does is nearly always harm in place. Left alone for years it can burrow through the epidermis into deeper skin, then into cartilage or bone, which matters most around the nose, eyelid and ear where there is little tissue to spare. Squamous cell carcinoma is the other common non-melanoma type, and the two are grouped together for that reason.
What raises the risk?
Cumulative ultraviolet light is the dominant factor, from sunlight and from tanning devices, so the head, neck, shoulders and backs of the hands carry most lesions. Fair skin that burns rather than tans, light eyes, older age and a history of previous skin cancer all raise it further. A suppressed immune system, such as after an organ transplant, raises it sharply. Rarer causes include earlier radiation treatment to the area, long-term arsenic exposure, and inherited conditions such as basal cell nevus syndrome, in which many lesions appear from a young age.
Also known as
Used in a sentence
A pearly, slow-growing lesion on the patient's nose was biopsied and confirmed to be basal cell carcinoma.
Good to know
Basal cell carcinoma rarely spreads to distant sites, unlike many other cancers, but it can destroy a great deal of nearby tissue if it continues to grow untreated over an extended period.
Word origin
Where “basal cell carcinoma” comes from
Formed from basal, from Greek basis, meaning base or foundation, and carcinoma, from Greek karkinoma, itself from karkinos, meaning crab.