Age Spot or Melanoma? How to Tell the Difference

A solar lentigo (the medical term for an age spot or liver spot) is a flat patch of increased pigment caused by accumulated UV damage. UV light triggers melanocytes to produce more melanin in localised areas, creating discrete brown spots. Once formed, age spots tend to be stable.

Typical features: flat (not raised); 3-15mm; uniform light to medium brown; smooth, well-defined oval or round border; on sun-exposed skin (face, backs of hands, shoulders, chest, upper back); appears after 40; multiple, often in similar groups.

Age spots are not 'liver spots' in the sense of being caused by liver problems — that is an old misconception. They are entirely sun-driven.

Lentigo maligna. Early in-situ melanoma on chronically sun-damaged skin. Looks like a large, slowly growing, irregularly shaped age spot, especially on the face. Median diagnosis age is 65-70. Often present for years before being noticed.

Lentigo maligna melanoma. The invasive form of lentigo maligna. Same lesion, but now invading deeper layers of skin. May develop a raised area, nodule, or change in colour within an existing 'age spot'.

Superficial spreading melanoma. The most common melanoma subtype overall, can occur on any sun-exposed skin. Usually has more dramatic colour variation than a typical age spot.

Pigmented basal cell carcinoma. A BCC that contains melanin, appearing as a brown or black papule or plaque. Less common than non-pigmented BCC. May have the typical pearly border with telangiectasia visible on close inspection.

Pigmented seborrheic keratosis. A benign growth that can look very dark and irregular. Distinguished by a 'stuck-on' appearance and rough, waxy surface. Frequently mistaken for melanoma but harmless.

Age spot: flat, smooth, level with surrounding skin. You can usually feel no difference between the spot and the skin around it when you run a finger over it.

Suspicious lesion: any raised area, papule, or nodule developing within or alongside what was previously a flat age spot is a major warning sign. The transition from flat to raised within an existing pigmented lesion is the typical pattern of lentigo maligna progressing to invasive lentigo maligna melanoma.

If you have an age spot that has developed a bump in the past 6-12 months, see a dermatologist within 4 weeks. This is one of the more reliable signals.

Age spot: well-defined, smooth, oval or round border. The pigment ends crisply at the edge.

Suspicious lesion: irregular, jagged, scalloped, or fading borders. The pigment trails off into surrounding skin in an asymmetric, uneven way. The B in ABCDE applied to lentigo maligna.

Age spot: uniform light to medium brown across the lesion. May have very subtle shading but no dramatic colour variation.

Suspicious lesion: multiple distinct shades — light brown, dark brown, black, grey, or even pink, red, or blue areas. The C in ABCDE. A 'liver spot' with three or more clearly different colours within it is a flag.

Grey or black areas within an age spot are particularly concerning, as is any pink or red discolouration appearing within a previously brown lesion.

Age spot: stable. May darken modestly with continued sun exposure, but does not enlarge significantly. The same age spot you had at 50 should look essentially the same at 60.

Suspicious lesion: growing — sometimes very slowly. Compare current spots to old photographs (vacation photos, weddings, family albums). If a 'liver spot' on the face has visibly enlarged or changed shape over 5-10 years, it deserves evaluation.

The slow growth pattern is what makes lentigo maligna so often missed. Year-over-year change is subtle. People do not notice their own face changing day-by-day. Photographs are the most useful tool here.

Age spot: no symptoms. Painless, non-itchy, does not bleed.

Suspicious lesion: itching, tingling, bleeding, scabbing, or any new sensation in a previously asymptomatic spot is a warning sign. Spontaneous bleeding from a pigmented lesion is a major red flag — not a feature of solar lentigines.

A single instance of bleeding after rubbing the spot with a towel is unlikely to be significant. Recurring bleeding or a non-healing surface is.

Age spot: usually known to the patient for years. People can often say 'I've had that one since my 40s.'

Suspicious lesion: new in the past 1-3 years, especially in someone over 60. New pigmented lesions in older adults are less common (most pigment changes happen in middle age) and have a higher prior probability of being melanoma in situ or another lesion that needs evaluation.

The rule of thumb: a new pigmented spot in a person over 60 is suspicious until proven otherwise.

Book within 2-4 weeks for any age spot or liver spot that is: developing a raised area within a previously flat spot; new in someone over 60; visibly enlarging over years; multi-coloured; bleeding or itching.

Book urgently (1-2 weeks) for: rapid change in size or colour; persistent bleeding; ulceration; nodule developing within an age spot.

Lentigo maligna and lentigo maligna melanoma are diagnosed by punch biopsy or excisional biopsy. Treatment of in-situ disease is wide local excision, with excellent cure rates and modest scarring. Treatment of invasive lentigo maligna melanoma follows standard melanoma protocols (excision, possible sentinel lymph node biopsy, possibly systemic therapy depending on stage). The advantage of catching it early — when it still looks like 'just an age spot' — is enormous.