What is basal cell carcinoma?|
A malignant tumour of the skin thought to arise from epidermal basal cells. It is locally invasive and rarely metastasises. It resembles the undifferentiated cells of the basal layer of the epidermis. When these cancers are detected and treated early the cure rate and prognosis is very high.
Causes and symptoms
In white populations, BCC is seen to be the most common cancer. It does occur in darker populations, but is not as prevalent. Light skin color, inability to tan and freckling in childhood are all predisposing factors. The cause behind the cancer is disputable.
Exposure to ultraviolet light has always been considered to be the primary cause, but it has been shown that about 20% of BCC have developed in non-sun exposed areas. Some studies suggest intermittent exposure, especially those resulting in sunburn, during childhood and adolescence may be important in the underlying cause of BCC. Chronic and occupational sun exposure, radiation therapy, treatment with arsenicals and a family history of skin cancer should also be taken into account.
BCC is commonly seen on the head and neck, but any area of the skin may be affected; however it does not occur on mucosal surfaces.
The most common clinical presentation of BCC is the nodular type. This appears as a raised dome-shaped, flesh colored spot on the surface of the skin with a pearly translucent boarder and an umbilicated or depressed center and a rolled boarder.
Occasionally there is mild oozing and crusting.The major clinical complication is local extension into other structures such as the sinuses or orbital areas.
Other variants include:
- Nodular or cystic - BCC looks tense and shiny.
- Superficial - A shiny thin patch or plaque. Usually slightly raised with a pink/red scaly, focally crusted surface and a thread-like boarder.
- Pigmented - ranging from a black pigment to a few specks, otherwise similar to the nodular type.
- Rodent ulcer - central depression forms a pit, which often oozes.
- Sclerosing, scarring, or morpheaform - A firm, fibrous reaction with small tiny pearly colored spots at the boarder. May extend deeply and more laterally and therefore is often more difficult to treat.
Examination of the skin area for evidence of solar damage and other tumors is necessary, as well as education about skin care in the sun.
In uncomplicated cases there is a success rate of about 95%. The site of the BCC as well as tumor type, age, and cosmetic desires all play a role in determining the type of procedure used.
- Topical application of fluorouracil (Efudex, Fluoroplex) is a good option for superficial BCC.
- Surgical excision is the most commonly used method, and often used if the BCC is small and simple. It is a quick procedure with few postoperative complications. Cosmetically the damage is minimal.
- Micrographic (Moh's) surgery is the most preferred treatment for difficult or recurrent BCC forms. The area is mapped and excised and margins checked immediately on frozen sections. If positive, then the areas are immediately removed, and this continues until all specimens are clear.
- Currettage and Electrodessication are used in simple, superficial lesions and can be used if the diameter is large. A scab forms post-therapy, and scarring is marked, but minimal on certain areas of the face.
- Cryotherapy is associated with tissue freezing using liquid nitrogen spray or applicators. A generous area is selected to ensure treatment is effective. Post-therapy pain, swelling, tissue necrosis and oozing may be persistent. There is very little scarring due to this procedure. This treatment avoids cartilage, and is useful to treat areas around the nose and ear regions.
- Radiation therapy is used only with complex tumors, but unlike Cryotherapy, it may be harmful to