Amelanotic Melanoma: The Skin Cancer That Doesn't Look Like One

Without pigment, the spot blends in. People put it down to a pimple, a bite, a blood blister or a scar, and doctors who aren't expecting a pink melanoma can make the same mistake. DermNet notes that patients and clinicians may not think of a non-pigmented spot as melanoma, that diagnosis is often delayed, and that amelanotic melanomas are often more advanced than pigmented ones when they're found ^[1].

It overlaps heavily with nodular melanoma, the fast-growing raised type: one in three nodular melanomas has no pigment ^[2]. So whether a spot is raised and growing matters more than its color.

There isn't one look. These are the common ones.

A pink or red bump. Smooth and dome-shaped, sometimes shiny. Easily taken for a pimple, a cyst or a basal cell carcinoma, but it doesn't clear up the way a pimple does.

A flat pink or red patch. Early lesions can be flat, uneven patches that are evenly pink or red ^[1].

A skin-colored spot. The classic description is simply skin-colored ^[1], which is why it can go unnoticed until it grows.

A red nodule that bleeds. A firm bump that may look like a blood-vessel growth and bleeds easily. Ulceration and bleeding are common in nodular melanoma ^[2].

A faint fleck of pigment. Some have a small brown or gray patch at the edge or in the middle. It's easy to miss, so look for it.

None of these matches the textbook melanoma photo, which is exactly why they get missed.

Pictures only go so far. With our photo skin cancer checker you can see which warning signs a photo of your own spot shows, with a suggested next step. It is paid and does not diagnose.

For raised spots, doctors add three checks to ABCDE: elevated, firm and growing ^[3].

Elevated: the spot stands up from the surrounding skin.

Firm: when you press it gently it feels solid, not soft like a pimple or a cyst.

Growing: it gets bigger over weeks. A pimple clears up, and a cyst tends to stay the same size. Australian melanoma guidelines say any spot that keeps changing or growing over more than a month should be removed or seen promptly by a specialist ^[4].

EFG applies to nodular melanoma in general, pigmented or not. In UK guidelines, a pigmented or non-pigmented lesion that suggests nodular melanoma is a reason for an urgent suspected-cancer referral ^[5].

Pyogenic granuloma. A red, fleshy bump that grows over a few weeks, often after a small injury, and bleeds very easily ^[6]. DermNet calls amelanotic melanoma its most important look-alike, even under the dermatoscope ^[6].

Cherry angioma. Small bright red bumps, usually several of them, that are harmless.

Basal cell carcinoma. A shiny, pearly pink bump, sometimes with fine vessels on the surface. It is the closest mimic, and it needs treatment too.

Molluscum contagiosum. Small pearly bumps with a dimple in the middle, mostly in children.

Telling these apart by eye isn't something you, or most family doctors, can do with confidence. A dermatoscope helps and a biopsy settles it. For you, the practical rule is simpler: a pink bump that is new, growing, bleeding or still there after a month should be looked at.

Anyone can. DermNet lists older age, very fair skin, red hair, heavy freckling and a tendency to burn as risk factors ^[1]. Amelanotic melanoma also makes up a significant share of the rare melanomas in young children ^[1], which is one reason a growing pink bump in a child should be shown to a doctor. A past melanoma, a family history of melanoma, many unusual moles and a weakened immune system raise the risk of melanoma in general.

Photograph it today with a ruler or coin for scale and note the date.

Book within 2 weeks: it is raised and firm, it has grown, it bleeds or crusts without an injury, or it has developed a fleck of pigment. If you've had melanoma before, or several of the risk factors above apply to you, book now rather than waiting for a second photo.

Book in the next few weeks: it's small, soft and not bleeding, but it's new and you can't explain it. Take a second photo after four weeks, and book sooner if it has changed.

When you book, describe it as 'a pink bump that is growing' rather than 'probably just a pimple'. At the appointment you can ask directly whether it could be an amelanotic melanoma.