Diagnosis & staging
More common skin cancers are
Basal Cell Carcinoma and Squamous Cell Carcinoma.
Another type of skin cancer is
Ocular melanoma is melanoma in the eye:
Moles, or nevi, are not usually cancers. However, melanoma often starts in a new or existing mole (nevus).
Melanomas can spread through the lymphatic system or blood stream.
Skin keeps moisture inside the body. It is part of the immune system.
Epidermis: outer layer of the skin.
- New skin cells are made in the bottom layer, called the basal layer.
- Contains melanocytes – cells that make melanin. Melanin gives your skin colour. Melanoma starts in the melanocytes.
Dermis: made up of connective tissue, blood vessels, and nerves.
- Contains hair follicles, sweat glands, sebaceous glands and nerve endings.
Hypodermis: made of fat and connective tissue.
Cancers of the skin are also called cutaneous cancers or dermatological cancers. Melanoma may also be called cutaneous malignant melanoma.
- Mole that changes shape or colour.
- Mole that is itchy or has a burning or tingling feeling.
- The ABCDE rule can help you look for common signs of melanoma. Talk to your doctor or nurse practitioner if you see any of these changes on your skin:
A is for Asymmetry - One half of a mole does not have the same shape as the other half.
B is for Border - The edge of the mole is uneven. The edge can be jagged, notched or blurry.
C is for Colour - The colour of the mole is not the same throughout. It can have shades of brown, black or tan. Sometimes there is blue, grey, red, pink or white.
D is for Diameter - The size of the mole is larger than 6 mm (1/4 inch) across. This is about the size of the eraser on the end of a pencil.
E is for Evolving - There is a change in the colour, size, shape or feel of the mole. The mole may be itchy or have a burning or tingling feeling.
If you have any signs or symptoms that you are worried about, please talk to your family doctor or nurse practitioner.
Tests that may help diagnose melanoma include:
Complete medical history: with a focus on skin problems or family history of skin cancer or other cancers.
Physical exam: a careful exam of skin all over your body, especially hard to see areas like the back of the neck, genital area, buttocks and scalp.
Excision biopsy: a doctor completely removes the mole or area of skin. If the area is quite large, only part of it may be removed. The tissue is then examined by a specialist doctor (pathologist) under a microscope.
Chest x-ray: to see if cancer has spread to the lungs.
Computerize Tomography (CT) scan: to see if cancer has spread.
Ultrasound: to see if cancer has spread.
Lymphoscintiscan: scan of lymph nodes near the area.
There are a few types of melanomas. All types can grow and spread quickly.
- About 66% (66 out of 100) of all melanomas.
- May start from an existing mole (dysplastic nevus).
- A nodule appears, usually not related to an existing mole.
- Less common.
- Most commonly appears on the sun-exposed faces of the elderly.
- Occurs on the palms or the soles of the feet or under the nail
- Accounts for the majority of malignant melanomas for dark-skinned people but for only a small percentage of all melanomas for light-skinned people.
Staging describes the cancer. Staging is based on how much cancer is in the body, where it was first diagnosed, if the cancer has spread and where it has spread to.
The stage of the cancer can help your health care team plan your treatment. It can also tell them how your cancer might respond to treatment and the chance that your cancer may come back (recur).
Stage 0 (melanoma in situ): Cancer cells are only in the top layer of the skin (epidermis). Sometimes called precancerous condition of the skin.
Stage 1A: Tumour is 0.8 mm thick or less and there is no ulceration of the tumour (there is no broken skin or open wound)
OR Tumour is more than 0.8 mm but not more than 1 mm thick and there may be ulceration.
Stage 1B: Tumour is more than 1mm thick but not more than 2 mm thick. No ulceration.
Stage 2A: Tumour is more than 1mm thick but not more than 2 mm thick and there is ulceration
OR Tumour is more than 2 mm thick and there is no ulceration.
Stage 2B: Tumour is more than 2 mm thick but not more than 4 mm thick and there is ulceration OR Tumour is more than 4 mm thick and there is no ulceration.
Stage 2C: Tumour is more than 4 mm thick. There is ulceration.
Stage 3: Cancer has spread to 1 or more lymph nodes near the cancer. After the lymph nodes are removed and examined by a pathologist, cancer is given stage 3A, 3B, 3C, or 3D. This staging depends on:
- Number of lymph nodes with cancer.
- How much cancer is in the lymph nodes.
- If the cancer has spread to nearby areas of the skin or lymph vessels.
Stage 4: Cancer has spread to other parts of the body (distant metastasis), such as the liver or lungs. This is also called metastatic melanoma skin cancer.