oPatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
Black and brown skin lesions can be considered as melanocytic neoplasms. The essential task is to exclude malignant melanoma. See also separate articles Malignant Melanoma of Skin and Skin Biopsy Techniques in General Practice. There are excellent photographs of skin lesions on the DermIS and DermNet websites (under 'Document references' 2 and 3 links, below).
Melanomas may have a variety of colours, including tan, dark brown, black, blue, red and occasionally light grey. Use the 7-point weighted checklist for assessment of pigmented skin lesions:
- Major features of lesions (2 points each):
- Change in size.
- Irregular shape.
- Irregular colour.
- Minor features of lesions (1 point each):
- Largest diameter 7 mm or more.
- Change in sensation.
- Lesions scoring 3 points or more in the 7-point checklist above are suspicious (if you strongly suspect cancer any one feature is adequate to prompt urgent referral). For low-suspicion lesions, undertake careful monitoring for change, using the 7-point checklist (see below) for eight weeks. The National Institute for Health and Clinical Excellence (NICE) recommends ideally making measurements with photographs and a marker scale and/or ruler.
- An alternative aide-mémoire to the 7-point checklist described below is the 'ABCDE' list:
- A symmetry.
- B order irregular.
- C olour irregular.
- D iameter greater than 7 mm.
- E volving.
- However, not all these features may be present and, if malignant melanoma cannot be excluded, then excision biopsy is required.
- Change in size: naevi may change in size over years, but any change over weeks or months is suspicious.
- Change in colour:
- Melanomas often show irregular pigment in a lesion, with shades of black, brown, grey, and pink. In nodular melanoma the lesion is often black throughout.
- Rarely, a melanoma can present as a non-pigmented red nodule (amelanotic melanoma), which is more likely on the hands and feet.
- Change in outline: melanomas often show a geographical outline with a sharp cut-off from normal skin.
- Itching may be a late sign and is often unreliable, as many benign naevi intermittently itch.
- Bleeding is also a late sign and is often present in advanced melanoma.
- Melanoma in women occurs more commonly on the extremities and in men on the trunk or head and neck, but it can arise from any site on the skin surface.
Multiple lesions with irregular pigmentation and edge
- Examination of suspicious lesions should include a thorough assessment for other suspicious skin lesions, palpation for regional lymph nodes and examination of the abdomen for enlarged liver and/or spleen.
Nodular melanomaNodular melanoma tends to lack the typical ABCDE melanoma warning signs and therefore may be diagnosed late with a much worse prognosis. A nodular melanoma most often presents on the legs and trunk. A nodular melanoma is usually uniform in colour with early ulceration and bleeding.
Multiple cutaneous melanomas
- About 3-5% of melanoma patients present with a second primary melanoma.
- Subsequent melanomas may appear at the same time or up to decades after the first primary melanoma, emphasising the need for thorough complete skin examination and continued careful self-examination and follow-up.
- The incidence of a second primary invasive melanoma has been shown to be increased in men and for initial melanoma thickness greater than 2 mm.
- Lesions may be classified as synchronous if they present at the same time or within two months, or metachronous if the second melanoma presents later.
Other causes of pigmented skin lesions
Also called common naevi. See separate article Intradermal and Compound Naevi.
Most adults will have approximately 30 moles which they have been acquiring from infancy. Naevi remain static whereas melanoma change in size, shape, or colour over weeks or months. New common moles rarely develop after age 40 years and any that do are suspicious.
Typical features of common naevi are:
- Symmetrical in area.
- Even, brown colouring (light or dark).
- Sharp margin.
- <5 mm in diameter.
- Profile varying from flat to pedunculated.
Anyone with >50 moles is at greatly increased risk of malignant melanoma, which may or may not arise from an existing mole. These patients need careful skin monitoring, including baseline skin photography. Any lesion that starts to change colour, bleed, itch, be painful or increase in size needs excisional biopsy.
Also known as dysplastic naevi. They are found in approximately 1 in 12 Caucasians and do not usually become evident until puberty. Unlike melanoma, atypical naevi are usually symmetrical and do not have a sharp edge with geographical border; asymmetry and sharp-edged borders are clear signs of malignant transformation. Atypical moles are easily mistaken for malignant melanoma because of their:
- Lack of symmetry.
- Lack of sharp margin.
- Size >6 mm.
- Variation in colour within the lesion.
Unlike common moles they continue to appear throughout life and occur in areas not often exposed to the sun, eg buttocks. They are a strong, independent risk factor for malignant melanoma, especially when they are present in numbers (12% risk over ten years). Patients should be very careful with sunlight and undergo regular skin surveillance. Excision of dysplastic naevi is not performed routinely.
See also separate article Congenital Pigmented Naevus. Very large congenital naevi are known as giant naevi. Patients with large congenital naevi have a risk of up to 10% of developing malignant melanoma, often by age 10 years. These appear either within the lesion or as CNS melanoma. Treatment is either excision or close monitoring. Laser treatment is also available.
See also separate article Blue Naevus. A blue naevus is a small blue or grey lesion, with an appearance similar to a mole. A newly occurring lesion may need excision biopsy to exclude nodular melanoma.
Spitz naevi usually affect the face or limbs of young children. They initially grow rapidly but may then remain static for years. They often disappear spontaneously after a period of time.
See separate article Epidermal Naevus.
- Epidermal naevi may be congenital lesions or develop during the early years of life. They tend to grow during childhood and then stabilise during the teenage years. They may be localised to a small area or occur in more diffuse forms.
- Epidermal naevus syndromes are a heterogeneous group of disorders characterised by the presence of one or more congenital hamartomatous ectodermal naevi of the skin with other organ involvement, including brain, eye and the skeleton.
- Becker's naevus: this is a form of epidermal naevus (birthmark). It usually appears around puberty as a hyperpigmented patch, most often found on the upper trunk or shoulders.
See separate article Halo Naevus. Usually, these consist of a central uniformly pigmented naevus, usually round or oval in shape, with a surrounding area of depigmentation of uniform width from the naevus's edge.
See separate article Junctional Naevus.
- Junctional naevi are often quite darkly pigmented and are macular or very thinly papular with only minimal elevation above the level of the skin.
- They are an acquired lesion and as they age they can change their characteristics to that of compound naevi.
See separate article Intradermal and Compound Naevi.
- Compound naevi arise from a flat (junctional) naevus that exists earlier in life. Pigmentation may be uneven within the naevus but is usually symmetrically distributed.
- They are usually of a round/oval shape and roughly 2-7 mm in diameter. They may exist with a variable degree of pigmentation and even be the same colour as the surrounding skin.
See also separate article Sebaceous Naevus. Usually a single hairless patch (round or linear) is noted on the scalp at birth or shortly afterwards. The classic appearance is velvety tan or yellow-orange.
See also separate Seborrhoeic Wart. A flat-topped or warty-looking lesion that appears to be stuck on to the skin. They are usually pigmented, sometimes deeply and may even be black.
Further reading & references
- Roth RR et al; Blue Nevi, Medscape, Jan 2012
- Revised U.K. guidelines for the management of cutaneous melanoma 2010, British Association of Dermatologists
- Cutaneous Melanoma, Scottish Intercollegiate Guidelines Network - SIGN (2003)
- DermIS (Dermatology Information System)
- Skin lesions, tumours and cancers, DermNet NZ
- Referral for suspected cancer; NICE Clinical Guideline (2005)
- Melanoma skin cancer, CancerHelp UK
- Swetter SM, Cutaneous Melanoma, Medscape, Nov 2011
- Carli P, De Giorgi V, Chiarugi A, et al; Multiple synchronous cutaneous melanomas: implications for prevention. Int J Dermatol. 2002 Sep;41(9):583-5.
- Kang S, Barnhill RL, Mihm MC Jr, et al; Multiple primary cutaneous melanomas. Cancer. 1992 Oct 1;70(7):1911-6.
- Brobeil A, Rapaport D, Wells K, et al; Multiple primary melanomas: implications for screening and follow-up programs for melanoma. Ann Surg Oncol. 1997 Jan;4(1):19-23.
- McCaul KA, Fritschi L, Baade P, et al; The incidence of second primary invasive melanoma in Queensland, 1982-2003. Cancer Causes Control. 2008 Jun;19(5):451-8. Epub 2008 Jan 1.
- Improving Outcomes for People with Skin Tumours including Melanoma (update): The Management of Low-risk Basal Cell Carcinomas in the Community; NICE (2010)
- Bataille V, de Vries E; Melanoma--Part 1: epidemiology, risk factors, and prevention. BMJ. 2008 Nov 20;337:a2249. doi: 10.1136/bmj.a2249.
- Schaffert A; CNS Melanoma, Medscape, Jan 2010
- Dave R, Mahaffey PJ; Combined early treatment of congenital melanocytic naevus with carbon dioxide and NdYag lasers. Br J Plast Surg. 2004 Dec;57(8):720-4.
Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.
Dr Richard Draper
Dr Colin Tidy
Dr John Cox