A Spot on the Sole That Won't Go Away — and Acral Melanoma

Why won't a spot on the bottom of my foot go away?

Feet take constant pressure and friction, so spots there are slow to settle and easy to re-injure: plantar warts, corns and calluses, a blood blister from a long day, a healing cut, or a patch of irritated skin. Most are harmless. The reason a persistent foot spot still deserves attention is that one form of melanoma appears on exactly this skin — the sole, which never sees the sun — and it is easy to mistake for a callus or a bruise. The large majority of spots on the sole are not cancer. But a wart or callus generally changes with time or treatment, while a spot that only persists, slowly grows, or looks unlike anything else on your foot is the one worth having examined rather than watched forever.

What acral melanoma can look like on the sole

The melanoma that turns up on palms and soles is called acral lentiginous melanoma, and it often begins as a flat brown or black patch with an uneven edge or more than one shade of color. Early on it can look deceptively dull — no lump, no pain. Dermatologists screen a changing pigmented spot with the ABCDE criteria: asymmetry, border irregularity, color variation, diameter larger than about 6 millimeters, and evolution over time 1Ref 1Tsao H, Olazagasti JM, Cordoro KM, et al. (2015).Early detection of melanoma: reviewing the ABCDEs.The ABCDE criteria (asymmetry, border irregularity, color variation, diameter over 6 mm, evolution) used to flag a pigmented spot for evaluation.. On the foot, though, the ordinary rules bend. Acral lentiginous melanoma is a recognized subtype that arises on the palms, the soles, and under the nails 2Ref 2National Cancer Institute (PDQ Adult Treatment Editorial Board) (2025).Melanoma Treatment (PDQ®)–Health Professional Version.Melanoma biology including the acral lentiginous subtype that arises on palms, soles, and nail units, and standard treatment options (surgical excision, sentinel lymph node biopsy, immunotherapy, targeted therapy).. Because it favors skin people rarely inspect and is not the sun-exposed skin most skin-cancer warnings describe, it can grow larger than the classic size threshold or hide under callus — one more reason a description or an online photo cannot settle what a spot is.

The ABCDE letters, read on a foot spot

The ABCDE letters give you a shared vocabulary for what to photograph and describe to a clinician — not a scoring system that rules cancer in or out. Each letter names a feature that makes a pigmented spot more worth examining. Apply them to a foot spot the way you would anywhere, and bring the answers, and your photos, to the visit 1Ref 1Tsao H, Olazagasti JM, Cordoro KM, et al. (2015).Early detection of melanoma: reviewing the ABCDEs.The ABCDE criteria (asymmetry, border irregularity, color variation, diameter over 6 mm, evolution) used to flag a pigmented spot for evaluation..

A single feature is reason enough to be seen — you do not need all five.

How quickly should I get a foot spot checked?

There is no benefit to waiting, and there is a real cost to it: melanoma found early is far more treatable than melanoma found late. A reasonable approach is to photograph the spot now — with a coin or ruler beside it for scale and in steady light — and then book a skin exam rather than watching for weeks. A spot that is bleeding, forming an open sore, spreading, or clearly changing between photos is a reason to be seen soon rather than eventually. Public advice can confuse this. The US Preventive Services Task Force concluded there is not enough evidence to recommend for or against routine whole-body skin checks in people without symptoms — but that finding is about symptomless screening and explicitly does not cover evaluating a spot you have already noticed 3Ref 3US Preventive Services Task Force (2023).Skin Cancer: Screening.USPSTF 2023 found insufficient evidence on routine whole-body visual skin screening in asymptomatic adults, and notes it does not address diagnostic evaluation of a lesion already noticed.. A non-healing foot spot is not screening; it is a reason to be examined.

How a spot on the foot gets diagnosed

Diagnosis is by biopsy, not by inspection. If a clinician thinks a pigmented spot could be melanoma, the preferred sample removes the whole lesion at full thickness — an excisional or saucerization biopsy — rather than a superficial shave or a small punch through part of it, because sampling the full depth preserves the thickness measurement that drives staging 4Ref 4American Family Physician (2011).Shave and Punch Biopsy for Skin Lesions.For a suspected melanoma, a narrow full-thickness excisional or saucerization biopsy sampling the whole lesion is preferred over a superficial shave or partial punch to preserve staging accuracy.. On the sole, where skin is thick and load-bearing, exactly how this is done is tailored to the site. The American Academy of Dermatology's melanoma guideline lays out these biopsy techniques, the surgical margins scaled to how deep a tumor goes, and when a sentinel lymph node biopsy is considered to check whether cells have reached the nearest nodes 5Ref 5Swetter SM, Tsao H, Bichakjian CK, et al. (2019).Guidelines of care for the management of primary cutaneous melanoma.AAD melanoma guideline: recommended biopsy techniques, surgical excision margins scaled to tumor thickness, and the role of sentinel lymph node biopsy.. None of this is decided from a photo — the tissue answers the question the eye cannot.

Why melanoma on the foot is so often caught late

Two things delay a foot melanoma. First, the sole is out of sight — most people never look there, so a spot can grow for months before anyone notices. Second, skin cancer is widely, and wrongly, assumed to be a fair-skin problem, which means melanoma on the foot in skin of color is checked for less often and found later. Acral melanoma in skin of color is a well-recognized pattern for exactly this reason, and late melanoma diagnosis is what turns a highly treatable cancer into a dangerous one. Skin cancer in skin of color earns its own attention because the sites differ — palms, soles, nails, and mouth rather than sun-exposed faces and arms. A black spot on the sole of the foot or a dark spot on the palm of the hand deserves the same scrutiny as a changing mole anywhere else. Checking your own soles, the spaces between your toes, and your nails, and asking someone to look where you cannot, closes part of that gap.

If a foot spot turns out to be melanoma

A melanoma diagnosis on the foot is frightening, but the number that matters most is how early it was caught. When melanoma is still confined to the skin, five-year relative survival is very high — on the order of 99% for localized disease — and it falls substantially once the cancer reaches lymph nodes or distant sites 6Ref 6National Cancer Institute, Surveillance, Epidemiology, and End Results (SEER) Program (2025).Cancer Stat Facts: Melanoma of the Skin.US melanoma five-year relative survival is very high for localized disease and falls substantially once it reaches regional nodes or distant sites.. That gap is the entire argument for having a changing spot looked at now rather than later. Treatment for early disease centers on surgical removal with a margin of normal skin; a sentinel lymph node biopsy may be used to check the nearest nodes; and for melanoma that has spread, immunotherapy and targeted therapy have changed what advanced treatment can achieve 2Ref 2National Cancer Institute (PDQ Adult Treatment Editorial Board) (2025).Melanoma Treatment (PDQ®)–Health Professional Version.Melanoma biology including the acral lentiginous subtype that arises on palms, soles, and nail units, and standard treatment options (surgical excision, sentinel lymph node biopsy, immunotherapy, targeted therapy).. The single biggest predictor of outcome is how early the spot is found — which is within reach when it is examined promptly.