Acral Lentiginous Melanoma (ALM), The Melanoma Most People Have Never Heard Of, And Why Early Detection Can Save Your Life

When most people picture melanoma, they imagine a suspicious mole on sun-damaged skin, the kind you might find on your back, shoulders, or chest after years of outdoor activity. But there's a type of melanoma that doesn't follow those rules. It shows up in places you'd never think to look, it affects people of all skin tones equally, and it's frequently caught too late because most people simply don't know it exists.

It's called Acral Lentiginous Melanoma, ALM for short, and it deserves far more attention than it gets.

What Is Acral Lentiginous Melanoma?

ALM is a rare but serious form of melanoma that develops on the palms of the hands, the soles of the feet, and under the fingernails or toenails. The word "acral" refers to the extremities of the body, and that's exactly where this cancer likes to hide.

Unlike other types of melanoma, ALM isn't caused by sun exposure. That distinction matters enormously, because it means the usual "protect yourself from UV rays" message doesn't apply here, and it also means people with darker skin tones are just as vulnerable. In fact, ALM accounts for a disproportionately high percentage of melanoma cases in Black, Hispanic, and Asian populations, and it's historically been diagnosed at later stages in these communities, often with worse outcomes as a result.

The reasons for this disparity are complex, but a lack of awareness is a major factor.

Why It's So Easy to Miss

Part of what makes ALM particularly tricky is location. Most of us don't spend much time scrutinizing the bottoms of our feet or the skin under our nails. These are easy-to-overlook areas that often get dismissed, especially when a spot appears gradually over months or years.

A lesion on the sole of the foot might be brushed off as a bruise, a callus, or simply a "dark spot." A discoloration under a toenail or fingernail might be attributed to trauma, a dropped object, tight shoes, or a sports injury. And because these spots aren't on the face or arms, they're far less likely to catch someone's attention in a mirror.

The slow, subtle growth pattern of ALM adds to the challenge. It often begins as a flat, irregularly shaped patch, tan, brown, or black, that slowly spreads over time. Without knowing what to look for, it's very easy to ignore.

What to Look For

The same "ABCDE" criteria used for other melanomas apply to ALM:

Asymmetry - One half doesn't match the other.

Border - The edges are irregular, ragged, or blurred.

Color - Multiple shades of brown, black, tan, or even pink and red may be present within the same lesion.

Diameter - Larger than 6mm (about the size of a pencil eraser), though ALM can be smaller in early stages.

Evolving - Any change in size, shape, color, or new symptoms like bleeding or itching.

For nail involvement specifically, look for a dark streak or band running lengthwise through the nail. This can look similar to a bruise, but a bruise will grow out with the nail, a melanoma won't. Another warning sign is dark pigment that extends onto the skin surrounding the nail, a phenomenon called Hutchinson's sign.

It's also worth mentioning: these signs don't always look dramatic. Early-stage ALM can be subtle. That's exactly why regular professional skin exams are so important.

Who Should Be Paying Attention?

Everyone. But there are a few groups who should be especially vigilant:

People with darker skin tones are statistically more likely to be diagnosed with ALM relative to other melanoma types. Because the myth persists that skin cancer isn't a concern for people of color, these individuals are also less likely to seek evaluation early, which is when treatment is most effective.

Athletes and active individuals who experience frequent foot trauma may be at higher risk, though the exact relationship between trauma and ALM is still being studied. If you regularly wear tight footwear or engage in high-impact activity, making nail and foot checks part of your routine is worthwhile.

Anyone over 50 should be particularly attentive. ALM tends to appear in older adults, though it can occur at any age.

Why Early Detection Changes Everything

Like most cancers, ALM is far more treatable when caught early. When the melanoma is confined to the outermost layers of skin (in situ or thin stage I), surgical removal is typically the primary treatment and prognosis is generally very good. As the cancer advances and spreads to lymph nodes or other organs, treatment becomes significantly more complex and outcomes less predictable.

The five-year survival rate for early-stage melanoma is dramatically higher than for late-stage disease. That's not a statistic to take lightly, it's a compelling reason to act sooner rather than later.

What this means practically: don't wait for something to look alarming before you get it checked. If you notice anything unusual on your palms, soles, or under your nails, even if it seems minor, have it evaluated. You're not being overcautious. You're being smart.

Make Skin Checks Part of Your Routine

Performing regular self-exams is a great habit to develop. Once a month, take a few extra minutes to examine your feet (including the soles and between your toes), your palms, and your nails. Use a mirror or ask someone you trust to help with hard-to-see areas.

But self-exams have their limits. A trained dermatologist can spot changes that are easy to miss with the naked eye, and they have the tools (dermoscopy, biopsy capability) to evaluate suspicious lesions properly. Annual professional skin exams are recommended for most adults, and more frequent visits may be appropriate based on your personal and family history.

If something has been nagging at you, now is the time to act.

Concerned about a spot on your foot, palm, or nail, or just overdue for a skin check? The team at Specialists in Dermatology is here to help. Our experienced dermatologists provide thorough, compassionate skin evaluations for patients of all skin types and backgrounds. Don't wait for "someday." Call us today at (520) 382 - 3330 or click book now to schedule your appointment. Early detection saves lives, and your skin health is worth prioritizing.