Author: Qiuyu Jin, Medical Student, University of Auckland, Auckland, New Zealand. DermNet Editor in Chief: Adjunct A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand. Copy edited by Gus Mitchell/Maria McGivern. June 2019. DermNet Update July 2021
Different pigmented lesion just to the left of the spine between the shoulderblades
The EFG of melanoma is another acronym designed to help the public and clinicians identify skin changes in a lesion suggestive of nodular melanoma.
Elevated
Firm
Growing
Asymmetry
A is for Asymmetry.
A melanocytic naevus (harmless mole) is usually symmetrical, whereas melanoma is often irregular or asymmetrical in shape and/or colour.
Asymmetry of shape and/or colour in a melanoma
Macro image of superficial spreading melanoma 8
0.8 mm lentigo maligna melanoma
Border irregularity
B is for Border irregularity.
A melanocyticnaevus has smooth, even borders, whereas a melanoma often has irregular, blurry, or jagged edges and hard-to-define border.
On careful inspection, the pigmented component of a flat melanocytic naevus fades out towards the edge, whereas the edges of a solar lentigo or a seborrhoeic keratosis are well defined. The edges of a melanoma tend to have both well-defined and fading segments.
B can also used for 'black', which is an uncommon colour for a melanocytic naevus in a white-skinned individual, but may be typical in skin of colour. The colour black however can occur in seborrhoeickeratoses in all skin types and ink spot lentigo in fair skin.
Borders of pigmented skin lesions
Melanocytic naevus with fading border
Seborrhoeic keratosis with sharp border
Melanoma with mixed sharp and fading border
Colour variability and Changing colour
C is for Colour variability.
A melanocytic naevus usually has a single shade of colour or two colours with one occurring inside the other or regularly repeated (generally pink, brown, or tan).
Variation in colour of melanocytic naevi
Pink dermal naevus
Melanocytic naevus
Dermal naevus
Melanoma can be brown (96%) but can have as many as five or six colours such as blue, black, tan, grey, pink, and red: 50% of melanomas include these uncommon colours. These colours are unevenly or irregularly distributed. C is also for Changing Colour.
Variation in colour of melanoma
Melanoma in situ
Invasive melanoma
Invasive melanoma
Different
D is for Different.
Most people have a 'signature naevus' - all their melanocytic naevi resemble each other. A melanoma appears unique and very different from the patient’s other lesions.
A pigmented lesion that is obviously different from the others is sometimes called an 'ugly duckling', 'black sheep', 'lone ranger', or 'odd-mole-out' and must be considered suspicious even if it does not fulfil the ABCDEFG criteria.
The melanoma is different from the other pigmented lesions
Evolving
E is for Evolving (changing).
A melanocytic naevus is usually stable and does not change in size, shape, or colour, whereas a melanoma changes over time. Change in size, colour, shape, or structure may be noted over months to years. However melanoma accounts for less than 3% of all changing skin lesions.
A nodular melanoma tends to grow rapidly with changes noted over days or weeks. Benign skin lesions tend to remain stable or change slowly over years to decades. Although they can rapidly change in appearance over hours to days if injured, inflamed, bleeding, or affected by eczema (eg, Meyerson naevus), they do not usually grow in size.
Nodular melanoma with EFG characteristics
Nodular melanoma
Nodular melanoma
Nodular melanoma
What other skin lesions might have ABCDEFG features?
Melanocytic naevi can also evolve in some circumstances such as darkening after exposure to the sun, during pregnancy, and become more elevated with age; seborrhoeic keratoses and solar lentigines routinely evolve over time.
Clinicians trained in dermoscopy can often correctly diagnose skin lesions, but sometimes a biopsy will be needed to confirm a diagnosis.
Benign melanoma mimics
Seborrhoeic keratosis
Solar lentigo
Melanocytic naevus
Do all melanomas display ABCDEFG characteristics?
While the ABCDEFG criteria has been proven to be very helpful in identifying a potential melanoma, they cannot be used to reliably recognise all melanomas. A melanoma may be symmetrical in shape, with a uniform border, and without much colour variation.
The ABCDEFG criteria are particularly unhelpful in the diagnosis of some less common subtypes of melanomas such as desmoplastic melanoma and melanoma in childhood, as these often lack the ABCDEFG features.
Melanomas without ABCDs
Nodular melanoma
Amelanotic melanoma
Small melanoma
Why are these ABCDE and EFG signs important?
Melanoma is a serious form of skin cancer and can progress quickly. It is treatable if identified early but if it is untreated, it may spread to other parts of the body (metastatic melanoma) and this can be life-threatening.
Knowing the ABCDE and EFG features of melanoma can help you look for early signs of melanoma when performing a regular self-skin examination.
I have a skin lesion I am concerned about, what should I do?
If you have a skin lesion with ABCDE or EFG characteristics that concerns you, see your doctor as soon as possible for assessment. You may be referred to a specialist for another opinion and surgery.
References
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Gachon J, Beaulieu P, Sei JF, et al. First prospective study of the recognition process of melanoma in dermatological practice. Arch Dermatol. 2005;141:434–8. PubMed
Grobb JJ, Bonerandi JJ. The 'ugly duckling' sign: identification of the common characteristics of nevi in an individual as a basis for melanoma screening. Arch Dermatol. 1998;134:103–4. doi: 10.1001/archderm.134.1.103-a. PubMed
Harrington E, Clyne B, Wesseling N, et al. Diagnosing malignant melanoma in ambulatory care: a systematic review of clinical prediction rules. BMJ Open. 2017;7:e014096. doi: 10.1136/bmjopen-2016-014096. PubMed
Jensen JD, Elewski BE. The ABCDEF rule: Combining the “ABCDE Rule” and the “ugly duckling sign” in an effort to improve patient self-screening examinations. J Clinical Aesthet Dermatol. 2015;8:15. PubMed Central
Whited JD, Grichnik JM. The rational clinical examination. Does this patient have a mole or a melanoma? JAMA. 1998;279:696–701. doi: 10.1001/jama.279.9.696. PubMed
Yagerman SE, Chen L, Jaimes N, Dusza SW, Halpern AC, Marghoob A. 'Do UC the melanoma?' Recognising the importance of different lesions displaying unevenness or having a history of change for early melanoma detection. Australas J Dermatol. 2014;55(2):119-24. doi:10.1111/ajd.12143 PubMed