Basal Cell carcinoma (BCC)
Basal cell carcinomas (BCC) or ‘rodent ulcers’ are the most common type (> 80%) of skin cancer (skin cancer incidence is < 1%) in the UK. The commonest cause is too much exposure to ultraviolet (UV) light from the sun or from sun beds and this explains why it is most common on sun exposed areas.
Apart from a rare familial condition called Gorlin’s syndrome, basal cell carcinomas are not hereditary.
What does basal cell carcinomas look like?
Basal cell carcinomas are very superficial and look like a scaly red flat mark: others have a pearl-like rim surrounding a central crater. They are slow growing and if left can erode the skin causing an ulcer – hence the name “rodent ulcer”. Some basal cell carcinomas are quite lumpy, with one or more shiny nodules with very small ‘spider like’ blood vessels running across the nodules.
The typical features of a basal cell carcinoma are:
- Slowly growing plaque or nodule
- Skin coloured, pink or pigmented
- Varies in size from a few millimetres to several centimetres in diameter
- Spontaneous bleeding or ulceration
What types of basal cell carcinomas are there?
- Most common type of facial BCC
- Shiny or pearly nodule with a smooth surface
- May have central depression or ulceration, so its edges appear rolled
- Blood vessels cross its surface
- Micronodular, microcystic and infiltrative types are potentially aggressive subtypes
- Most common type in younger adults
- Most common type on upper trunk and shoulders
- Slightly scaly, irregular plaque
- Thin, translucent rolled border
- Usually found in mid-facial sites
- Scar-like plaque with indistinct border
- May infiltrate cutaneous nerves (perineural spread)
- Mixed basal cell carcinoma (BCC) and squamous cell carcinoma (SCC)
- Infiltrative growth pattern
- Potentially more aggressive than other forms of BCC
How will my basal cell carcinoma be diagnosed?
Sometimes the diagnosis is clear from its appearance. If further investigation is necessary a small area of the abnormal skin (a biopsy) or all of the lesion (an excision biopsy) may be cut out and examined under the microscope. You will be given a local anaesthetic beforehand to numb the skin.
What is the treatment for primary basal cell carcinoma?
The treatment for a BCC depends on its type, size and location, the number to be treated, patient factors, and the preference or expertise of the doctor. Most BCCs are treated surgically. Long-term follow-up is recommended to check for new lesions and recurrence; the latter may be unnecessary if histology has reported wide clear margins.
Most appropriate treatment for nodular, infiltrative and morphoeic BCCs and should include 3 to 5 mm margin of normal skin around the tumour. Larger lesions may require a skin flap or skin to repair the defect from where the skin cancer was removed.
Mohs surgery involves examining carefully marked excised tissue under the microscope, layer by layer, to ensure complete excision. This is performed while the patient is still in the operating room. When Mohs surgery is not available, surgeons perform a delayed or ‘Slow Mohs’ when the surgical defect is dressed and the sample is sent to the histopathology and the patient returns at another appointment to have the surgical defect closed.
Superficial skin surgery
Superficial skin surgery includes curettage, shave and electrocautery. These techniques are suitable for small, well-defined nodular or superficial BCCs.
Cryotherapy is the treatment of a superficial skin lesion by freezing it with liquid nitrogen. Cryotherapy is suitable for small superficial BCCs on covered areas of trunk and limbs. The treatment can leave a permanent white mark on the skin.
Photodynamic therapy (PDT) refers to a technique in which BCC is treated with a photosensitising chemical, and exposed to light several hours later. Topical photosensitisers include aminolevulinic acid lotion and methyl aminolevulinate cream. PDT is suitable for low-risk small, superficial BCCs or multiple BCCs and large areas of filed changes.
Imiquimod is an immune response modifier.
5-Fluorouracil is a topical cytotoxic agent