In short. How melanoma is recognised with the ABCDE rule, why Breslow thickness and ulceration drive prognosis, and what excision and surveillance involve.
Key points
- Once melanoma is confirmed, the single most important number in the report is Breslow thickness — how deeply the tumour has invaded, measured to the nearest fraction of a millimetre.
- Ulceration under the microscope is the second.
- A thin melanoma confined to the upper dermis has an excellent long-term outlook after complete excision.
Melanoma arises from melanocytes, the cells that produce pigment. It accounts for only a small fraction of skin cancers and the great majority of skin cancer deaths, because unlike basal and squamous cell carcinoma it can spread through lymph channels and blood while the primary tumour is still small. It is also, when caught thin, one of the most curable cancers there is. Almost everything about melanoma comes down to how early it is found.
Recognition and the ABCDE rule
The ABCDE rule is the standard aid to recognising a melanoma: Asymmetry, where one half does not match the other; Border irregularity, with ragged, notched or blurred edges; Colour variation, with several shades of brown, black, red, white or blue in one lesion; Diameter, commonly greater than six millimetres, though melanomas can be smaller; and Evolution, meaning any change in size, shape, colour, height or symptom such as itching or bleeding. Evolution is the most important of the five, and a lesion that is changing outranks a lesion with an impressive score.
Thickness is the prognosis
Once melanoma is confirmed, the single most important number in the report is Breslow thickness — how deeply the tumour has invaded, measured to the nearest fraction of a millimetre. Ulceration under the microscope is the second. A thin melanoma confined to the upper dermis has an excellent long-term outlook after complete excision. A thick or ulcerated melanoma carries a substantial risk that microscopic deposits have already travelled beyond the skin, and that risk cannot be surgically removed. This is the entire argument for early recognition: nothing in treatment matters as much as what the pathologist measures on the day of removal.
Other features that matter
The report also notes whether the lesion is ulcerated, how many cells appear to be dividing, whether there is invasion into small vessels or nerves, and whether the tumour has regressed or is arising in a pre-existing mole. These features refine the estimate of risk. In higher-risk melanomas, sampling the first draining lymph node is discussed, because it identifies people who may benefit from further treatment and closer surveillance, even though the test does not improve survival on its own.
Excision and surveillance
The diagnostic excision is followed by a wider excision, whose margin is set by the thickness of the tumour rather than by preference. Thin melanomas need a narrow margin; thick ones need more, and sometimes a repair that takes function and appearance into account. After that, follow-up is structured by risk: skin checks for new primaries, examination of the draining node field, and imaging or blood tests in selected higher-risk patients. New melanomas, not only recurrences, are a real risk in people who have had one.
Seek review promptly if
- A mole changes in size, shape, colour or height, or becomes itchy, painful or tender.
- A mole bleeds, crusts or fails to heal, or a new dark lesion appears after the age of forty.
- You notice a new lump under the skin near a melanoma scar, or swelling in the nearest limb.
Frequently asked questions
Which part of the ABCDE rule matters most?
Evolution, meaning any change in size, shape, colour, height or symptom such as itching or bleeding. A lesion that is changing outranks a lesion with an impressive score on the other four features, and change is what usually prompts a biopsy.
What does Breslow thickness mean for prognosis?
It is how deeply the tumour has invaded, measured to the nearest fraction of a millimetre, and it is the single most important number in the report. A thin melanoma confined to the upper dermis has an excellent long-term outlook after complete excision, while a thick or ulcerated one carries a substantial risk of spread.
How is the margin for the wider excision decided?
By the thickness of the tumour rather than by preference. Thin melanomas need a narrow margin, while thick ones need more, and sometimes a repair that takes function and appearance into account. The diagnostic excision is always followed by this wider excision.
Risks & Limitations
- Incomplete excision, which may require a further operation to achieve clear margins.
- Recurrence of the skin cancer, and the need for surveillance for years afterwards.
- Scars are permanent. They mature and fade but never disappear.
- Problems with a graft or flap, including partial or complete loss, which may need further surgery.
- Numbness, altered sensation or nerve injury around the operated area.
- Melanoma carries a risk of spread that surgery cannot remove, even when the excision is complete.
- Pigment change, contour irregularity, or a scar that widens or thickens.
- Final assessment of the scar is made at 6–12 months, and surveillance continues longer.
When to Seek Care
- A lesion that changes in size, shape, colour or height, or that starts to bleed or itch.
- A new, rapidly growing nodule, or a sore that is not healing.
- A mole that becomes painful or bleeds.
- Swelling in a lymph node region — the neck, armpit or groin.
- A graft or flap that turns dark, cold or black, or a wound that opens or discharges.
- Fever above 38 °C, or spreading redness, warmth or pain around a wound.
References & Further Reading
- American Academy of Dermatology (AAD) — skin cancer diagnosis and treatment guidance
- American Cancer Society (ACS) — skin cancer types, staging and outlook
- Skin Cancer Foundation — prevention and skin self-examination resources
- American Society of Plastic Surgeons (ASPS) — reconstruction after skin cancer excision
- Cochrane Library — systematic reviews in skin cancer treatment and prevention
- Chinese Medical Association — clinical guidance for skin tumours and dermatologic surgery
This page is patient education, not medical advice, and it does not cite individual studies. Discuss your own case with a qualified clinician. To arrange an assessment at Chongqing West District Hospital, see Contact & Consultation.