Comprehensive Guide to Skin Cancer Types, Signs, and Biopsy Procedures
Understanding Skin Cancer and Diagnosis
Skin Cancer Signs & Symptoms
Skin cancers—including melanoma, basal cell carcinoma, and squamous cell carcinoma—often start as changes to your skin that are noticeable. They can be new growths or precancerous lesions—changes that are not cancer but could become cancer over time. Learning to spot the early warning signs can prevent serious issues in the future. Most types of skin cancer can be cured if found and treated early.
Melanoma
Because melanoma is a type of cancer that is likely to spread, catching it early can greatly improve your chance of being cured.
In general, keep an eye out for moles or any such skin blemishes that are changing, new, or in any way unusual. Melanomas can appear on parts of the body that are exposed to sun, as well as areas that stay covered. While this cancer can develop anywhere, in women it frequently shows up on the legs, and in men it frequently shows up on the torso of the body.
In particular, watch any moles for the “ABCDE” warning signs of melanoma. If you notice any of these symptoms, see your dermatologist.
Asymmetry (A):
Unlike a common mole, which tends to be symmetrical, one side of a melanoma doesn’t match the other.
Border (B):
Unlike the smooth edges of a common mole, melanoma borders appear uneven, possibly with notched or scalloped edges.
Colour (C):
While moles are usually a consistent brown colour, melanomas could have shades of tan, black, or brown. Red, blue, or white may also appear as melanoma grows.
Diameter or Dark (D):
If a lesion is as large as the diameter of a pencil eraser (1/4 inch) or if it appears unusually dark, it could be melanoma.
Evolving (E):
Changes in colour, shape, or size, or new symptoms such as itching, crusting, or bleeding could all indicate melanoma.
Basal Cell Carcinoma
Basal cell carcinoma often appears as a slightly translucent bump on the skin, though it can take other forms. You may be able see a bit through the surface, and tiny blood vessels are often visible. In people with darker skin tones, the lesion may be darker but still somewhat translucent. Basal cell carcinomas can also look like open sores, red scaly patches, scar-like growths, or a brown, black, blue, or pink lesion. At times, basal cell carcinomas may ooze, crust, itch, or bleed. The lesions commonly appear in sun-exposed areas of the body. It’s important to note that basal cell carcinoma can look quite different from one person to another.
Bowen’s disease
Bowen’s disease is a form of skin cancer affecting the upper layer of skin (epidermis); it is considered a squamous cell carcinoma in situ. Most of these lesions are due to chronic ultraviolet radiation, typically from the sun. It most commonly affects the head, neck, trunk, arms or lower legs. If left untreated, Bowen’s disease can progress into invasive skin cancer referred to as squamous cell cancer (SCC).
Actinic Keratoses (AK): The Earliest Skin Cancer
Actinic keratoses are considered the earliest stage in the development of skin cancer. They are small red rough spots most commonly found on the face, ears, neck, lower arms, and back of the hands in fair-skinned individuals who have had significant sun exposure. Actinic keratoses can be treated by cryotherapy (freezing), topical chemotherapy (applying a cream or lotion), chemical peeling, dermabrasion, laser surgery, curettage, and photodynamic therapy (a chemical is applied to the skin prior to exposure to a light source). Proper use of sunscreens can help prevent actinic keratoses even after extensive sun damage has already occurred.
Squamous Cell Carcinoma
Squamous cell carcinomas can appear as rough, scaly patches that may crust or bleed. The skin around them usually shows signs of sun damage such as wrinkling, pigment changes, and loss of elasticity. They typically appear on sun-exposed skin, but they can occur anywhere—including the inside of your mouth, the bottoms of your feet, and on the genitals. Squamous cell carcinomas can also look like warts, sores, or firm, red nodules. They can also show up as growths that are raised at the edge with a lower area in the centre that may itch or bleed.
Merkel cell carcinoma
Merkel cell carcinoma (MCC) is a highly aggressive form of skin cancer. It occurs most commonly on the head and neck, appearing as a painless, flesh-coloured, red or purple nodule (lump).
Given its innocuous appearance, MCC can often be dismissed as harmless or benign (non-cancerous). As a result, there can be a delay in diagnosing MCC, meaning it has time to spread and has a higher chance of coming back in nearby lymph nodes or elsewhere in the body, even after it has been treated.
Treatment of MCC may involve a combination of surgery, medicines and radiotherapy. As such, cases of MCC are often discussed at multidisciplinary team meetings where multiple specialists from various specialties can recommend the best treatment for the patient.
Other rarer skin cancers
There are number of other rare types of skin cancer, including:
- sebaceous carcinoma
- eccrine carcinoma
- dermatofibrosarcoma protuberans (DFSP)
- atypical fibroxanthoma
- undifferentiated pleomorphic sarcoma (formerly malignant fibrous histiocytoma, MFH)
- angiosarcoma
- Kaposi sarcoma
