A number of scoring algorithms, such as the 3-point and 7-point checklists, can be used in the dermoscopic assessment of melanocytic lesions. While they can help in the assessment of skin lesions, they do have flaws and the PCDS does not recommend that they be relied on for deciding whether or not any given lesion is benign or malignant.
Dermoscopy should never be relied upon as the sole tool in diagnosing skin lesions - a good history and careful naked-eye examination are also needed. The algorithm below can help you work through any given skin lesion.
Notes about the algorithm
Step I: history and naked-eye examination
- At presentation a concise history and naked-eye examination are necessary
- It may be possible at this stage to make a diagnosis of a benign lesion or of one that is suspicious of malignancy
If needed refer to the skin lesion diagnostic table on this website
Step 2: dermoscopic evaluation is likely to be of value in the following:
Pre-malignant tumours and BCC
Step 3: dermoscopic evaluation of melanocytic lesions
Benign melanocytic lesions
- Atypical melanocytic naevi
Considerable experience is often required to differentiate between various benign melanocytic naevi, atypical naevi and melanoma, indeed some cases of melanoma have very subtle dermoscopic features. As such all melanocytic lesions that are suspicious of melanoma in terms of the history and naked-eye examination should be referred urgently to Secondary Care as a 2 Week Rule, regardless of their dermoscopic appearance
Step 4: unknown, the safety net
- In some instances, following on from clinical and / or dermoscopic evaluation, the diagnosis may not be clear
- In such cases it can be difficult to rule out subtle melanomas and other skin cancers, and so urgent referral to a dermatologist as a 2 Week Rule is recommended