Moles are ordinary clusters of pigment cells in the skin, and almost all of them stay harmless for a whole lifetime. What matters is not how many you have, but whether one of them is changing - because a changing mole is the earliest sign of melanoma, and the earliest melanoma is the one that is easiest to cure. Melanoma is a skin cancer that starts in the cells that make pigment. It is much less common than other skin cancers but causes most skin cancer deaths, because it can spread. Found and removed while it is still thin, it is usually curable.
The same eight facts on every condition comparison.
They are clusters of pigment cells.
Moles are usually benign collections of melanocytes.
They vary in appearance.
They can be flat or raised, skin-colored or pigmented.
They appear at different times.
Some are present at birth; others appear later.
New or changing moles need a check.
A stable familiar mole differs from an evolving lesion.
It is a pigment-cell cancer.
Melanoma arises from melanocytes, the cells that produce pigment.
It can look many ways.
It may be dark, multicolored, pink or almost unpigmented.
Early assessment matters.
Invasive melanoma can spread beyond the skin.
Uncertain spots should not be removed at home.
Biopsy, not cosmetic removal, is the right step.
Common mole Small, round, even color.
Atypical mole Larger, uneven border or color.
Congenital mole Present from birth.
Halo nevus Generated illustration. Mole surrounded by a pale ring.
Blue nevus Small blue-gray mole.
Superficial spreading melanoma The most common, a growing flat spot.
Nodular melanoma A fast-growing raised bump.
Lentigo maligna melanoma Slow, flat brown patch on sun-damaged skin.
Acral lentiginous melanoma On palms, soles or under nails.
Moles form when benign pigment cells cluster into small nests. The location and arrangement of these cells help explain why some moles are flat and others are raised.
Abnormal pigment cells escape normal growth controls and multiply within the skin. Some melanomas grow into deeper tissue, and the depth of invasion helps determine their stage.
Moles. Most ordinary moles appear during childhood and adolescence; new or changing adult lesions deserve attention.
Melanoma. More common in adults, but a concerning changing lesion needs assessment at any age.
Moles form when pigment cells grow in a cluster instead of spreading through the skin. Most appear in childhood and early adulthood.
Melanoma starts when pigment cells develop DNA damage and grow out of control. Ultraviolet light is the main cause of that damage for most melanomas.
The number of moles you have is largely inherited.
About 1 in 10 people with melanoma have a family history of it. Genes such as CDKN2A raise the risk.
Evidence labels come from each condition’s own treatment list.
The standard for any mole that is genuinely in doubt: the whole mole is cut out under local anesthetic with a narrow margin of normal skin and sent for examination under a microscope. Taking all of it matters, because the pathologist has to see the full depth and the edges. It leaves a line scar, and results come back in a week or two.
A raised mole that catches on a razor or a collar can be shaved off flush with the skin under local anesthetic, leaving a flat pale mark rather than a line scar. It is a reasonable choice for a mole that is not suspicious, and the tissue still goes to the laboratory. Two honest limits: pigment left at the base can grow back, and a shave through a melanoma cuts across it rather than under it.
A small circular blade removes a small mole whole, down through the full thickness of the skin, and it is closed with a stitch or two. It suits moles smaller than the punch. Used to take a sample from part of a larger suspicious mole it can under-read the depth, so for those an excision is the better choice.
The treatment that cures the great majority of thin melanomas. Once the diagnosis is confirmed, a second and wider operation removes a margin of surrounding skin, with the width set by how thick the melanoma was. The scar is longer than most people expect, and that is the trade that stops it coming back at the site. Anything pigmented that is removed, anywhere, should be sent for pathology.
Above a certain thickness, the first lymph node the area drains to is located with a tracer and removed to see whether cells have reached it. It is a staging test rather than a treatment: it tells you where you stand and shapes what is offered next. It carries its own risks, including lasting swelling of the limb, so it is offered as a discussion rather than an automatic step.
Used at some centers for lentigo maligna on the face, where sparing skin matters and the true edge of the pigment is hard to see. It is not the standard operation for melanoma generally — wide excision is, and the evidence sits with that. If Mohs is offered to you, it is fair to ask why it suits this particular lesion in this particular place.
Nothing diagnoses melanoma except a biopsy. Where it is possible, the whole spot is removed with a narrow margin rather than sampled, because the pathologist needs the full depth to measure the thickness, and thickness sets everything that follows. It is done under local anesthetic and usually takes under half an hour. A biopsy does not make melanoma spread, and believing that it does is a common cause of delay.
Most moles remain harmless, but their appearance can change over a lifetime. A changing mole, a new unusual pigmented spot or one that looks different from the others needs examination. Monitoring should follow the person's individual risk.
Melanoma does not progress on a fixed schedule. Some variants change over years, others over weeks, so this is the sequence, not a timetable. Skin checks continue for years after treatment, because a second melanoma and a recurrence are both possible, and close relatives are usually advised to have their skin checked.
Most moles are benign. Having many or atypical moles can mark increased melanoma risk, and a changing lesion should be examined rather than assumed to be an ordinary mole.
Cells travel to the nearest nodes first
A lump near a previous melanoma site is significant and checked promptly.
Treated by an oncology team
Melanoma can spread to organs far from the skin. Immunotherapy and targeted therapy have changed outcomes substantially in the last decade.
Arrange prompt assessment for an evolving, unusual or bleeding mole. Comparing a spot with your other moles is useful, but photographs cannot confirm a diagnosis.
Arrange prompt assessment of a new or changing unusual spot, especially an evolving lesion or one that bleeds. Diagnosis requires clinical evaluation and usually biopsy.
Use two checks together. ABCDE covers asymmetry, an uneven border, more than one color, a diameter above about 6 millimeters, and - most important - evolving, meaning changing. The ugly duckling check asks whether the mole looks like your others. A spot that fails either, or passes both but keeps changing, should be examined in person.
New moles keep appearing through the teens and twenties and become uncommon after about 40. Many new pigmented spots in older adults turn out to be seborrheic keratoses or sun spots. That is a reason to have a new spot identified, not to assume it is one of those.
Yes, and it is a reasonable request. What matters is how it is done — cut out under local anesthetic and sent to a laboratory. Lasering, freezing or burning leaves nothing to examine, so ask for the version that gets checked.
No. Your risk is higher than average and regular checks are worth doing, but most people with a high mole count never develop melanoma. The response is a schedule of skin exams, not worry.
Yes — most melanomas arise on skin that had no mole before. That is why a new spot that grows, or a sore that will not heal, deserves the same attention as a changing mole.
Moles commonly darken slightly in pregnancy, and skin stretching over a growing abdomen or breasts can change a mole's shape. Melanoma does occur in pregnancy, though. A mole that changes in shape, border or color should be looked at while you are pregnant, not after.
It varies more than people expect. The common superficial spreading variant often changes over months to a few years. Nodular melanoma can grow downward over weeks to a few months. You cannot tell which you have by looking, so a changing spot gets examined now, not in six months.
No, and this belief causes delay. Removing a suspicious lesion is how melanoma is diagnosed and how the thickness is measured, and thickness determines the treatment. There is no evidence a biopsy spreads it.
No. Most melanomas arise as new spots, so removing moles does not remove the risk and means many scars for no benefit. Many or unusual moles are a reason for regular examinations, not preventive removal.
Usually not. Pigmented nail bands are common and often normal in deeper skin tones, frequently on several nails at once. It needs examining if it is on one nail only, if it is getting wider, if it has more than one shade, if the nail is splitting, or if the pigment spreads onto the skin around it.
The melanoma is treated, but you are not discharged. Having had one raises the chance of a second, so skin checks continue for years, and close relatives are usually advised to have their skin examined. Ask how often yours should be and who arranges it.
Yes. Sun exposure raises risk, but melanoma also occurs on soles, palms, under nails and on skin never exposed, and in people who have never burned. Sun history changes your risk profile, not whether a particular spot should be looked at.
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