Acral Nevus ICD-10: D22.6

Benign pigmented lesion / Melanocytic nevus

Often searched as: dark spot on bottom of foot, mole on sole of foot, brown spot on palm of hand, pigmented spot on foot, dark mark under toenail, mole on foot, black spot on sole, is a mole on foot dangerous…

Clinical urgency level

lowmediumhigh

Systems Affected

skin (palms, soles, nail unit)

Severity Levels

mild

Stable, symmetric, uniformly pigmented acral nevus with no change over time — regular monitoring sufficient.

moderate

Acral nevus with irregular borders or streaks but stable on serial dermoscopy — requires dermatologist evaluation and follow-up imaging every 6–12 months.

severe

Any acral pigmented lesion showing rapid change, asymmetry, color variation, or bleeding — must urgently rule out acral lentiginous melanoma.

Red Flags

A pigmented spot on the sole or palm that is growing or changing
Irregular, asymmetric, or multi-colored pigmentation on the sole
A dark streak under a toenail or fingernail (especially if new or expanding)
Any acral lesion larger than 7mm
Bleeding or ulceration of a pigmented spot on the foot or hand
A new dark spot on the sole in a person over 50 — higher melanoma risk

Clinical Presentation

Acral nevus — uniform brown macule on the plantar surface

View gallery on DermNet NZ (image gallery reference)

Acral lentiginous melanoma vs acral nevus — comparative dermoscopy reference

Source: Wikimedia Commons (CC BY-SA 3.0 )

When to See a Doctor

See a dermatologist for any new or changing pigmented spot on your palm, sole, or under a nail — especially if you are of East Asian, African, or Hispanic descent, where acral lentiginous melanoma is proportionally more common. Dermoscopy by a trained dermatologist is the gold standard for evaluating acral lesions.

Differential Diagnosis

Acral lentiginous melanoma (most critical — asymmetric, irregular, changing)
Subungual melanoma (dark streak under nail — Hutchinson's sign if extends to nail fold)
Plantar wart (rough, black dots — viral cause)
Blood blister / hematoma (dark, history of trauma — resolves with nail growth)
Talon noir (black heel — friction hemorrhage in athletes)
Blue nevus (blue-gray, uniform)

Comorbidities

Dysplastic nevus syndrome (higher overall nevus burden)
Personal or family history of melanoma
Immunosuppression (higher malignant transformation risk)

Prognosis

Acral nevi are benign and the vast majority remain stable throughout life with no malignant potential. The challenge is clinical and dermoscopic distinction from acral lentiginous melanoma (ALM), the most common melanoma subtype in darker-skinned populations. When an acral nevus is excised due to diagnostic uncertainty, the prognosis is excellent. ALM caught early (thin lesion) also has a favorable prognosis (>90% 5-year survival). Regular dermoscopic monitoring every 6–12 months is standard practice for atypical acral lesions.

Detailed Overview

Causes, Symptoms, and When to Take Action An acral nevus is a benign melanocytic lesion that appears on the skin of the palms, soles, or nail units. It typically occurs on non-hair-bearing areas of the hands and feet and is considered harmless. How It Looks Texture: Usually a flat or slightly elevated macule or papule Color: Uniform brown to black pigmentation Shape: Typically symmetrical and well-defined, although some may appear asymmetrical or irregular Location: Commonly found on the palms, soles (especially the arch), and nail apparatus Why Does It Appear? The exact cause of acral nevus remains unclear. Genetic factors may play a role, and chronic pressure or trauma to the skin may contribute in some cases. These lesions are genetically distinct from acral melanoma and generally show stable benign characteristics. Should You Be Concerned? Acral nevi are benign and rarely transform into melanoma. However, it's important to remain vigilant. Consult a healthcare provider if the lesion: Changes in size, shape, or color Grows beyond typical dimensions or develops an irregular appearance Differs significantly from your other moles Can You Prevent It? There's no known prevention for acral nevi. Regular skin monitoring is advised, especially for lesions in areas subject to friction or pressure, and if multiple nevi are present across the body. 👉 How Piel AI Can Help Piel AI supports you in tracking lesions over time using regular imaging. While it does not diagnose, it helps detect subtle changes in shape, color, or size, and supports discussion with healthcare professionals. Summary Acral nevus is a benign mole occurring on the palms, soles, or nails. It's usually symmetrical, uniformly pigmented, and stable. Rarely progresses to melanoma, but changes should prompt evaluation. Regular visual monitoring helps ensure ongoing skin health.

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