Dermatology Case Studies

Clinical Assessment of a Lesion

She has attached a photograph of the lesion:

Figure 4: Pink lump with white centre, under the skin

You assess this photograph according to the ABCDE criteria, a very useful system for examining most skin lesions

Click each of letters of the mnemonic to reveal the assessment:

A is for Asymmetry

A dermatofibroma is usually symmetrical, whereas melanoma and more concerning skin lesions are often irregular or asymmetrical in shape and/or colour
In this case you can clearly see the spot is symmetrical

B is for Border irregularity

A dermatofibroma usually has smooth, even borders, whereas skin cancers often have irregular, blurry, or jagged edges and hard-to-define border
In this case you can clearly see the photograph shows a well circumscribed nodule with a smooth and regular border

C is for Colour variability and/or Changing colour

A dermatofibroma will usually have a central white area in the middle with a pigmented area surrounding it as seen in the image sent by the patient
This would not normally be a feature of melanomas and more concerning skin lesions
The colour demonstrated is a reassuring feature here
It should be noted, however, that the overall colour of dermatofibromas can be pink to light brown in white skin, and dark brown to black in dark skin, hence it is important to carefully check all skin lesions using the ABCDE criteria

D is for Different

Dermatofibromas may occasionally erupt in multiples, particularly in patients with underlying immune suppression
Where patients have multiple, you would expect them to look broadly similar
Any that did not, would warrant special attention
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 ABCDE criteria
Comparing this lesion to the patient's other moles is something that may be useful if you were seeing this patient face-to-face
However, based on image sent by the patient, this is not suggestive of malignancy

E is for Evolving (changing)

Once formed, a dermatofibroma is usually stable and does not change in size, shape, or colour, whereas a melanoma changes over time
In this case the patient is telling you she has just noticed this lesion recently so not much comment can be made here but any change in size, colour, shape, or structure of high-risk lesions should be monitored