The medical importance of moles has to do with their relationship to melanoma, which is the malignant version of a mole. When melanoma is diagnosed early it has a simple and effective surgical treatment but diagnosed late metastases are frequent and mortality is high. The importance of moles in relation to melanoma is threefold:
1. Moles are risk markers for melanoma: melanoma is more frequent in people with many moles and/or atypical moles.
2. Moles can be melanoma simulators: digital dermoscopy makes it easier to differentiate atypical moles from incipient melanomas because we can see structures and colors in them that are not visible to the naked eye and we can monitor their evolution and see early which moles present problematic changes.
3. Some moles can be precursors of melanoma: some melanomas arise from healthy skin (like a new mole) but others derive directly from a previous mole, stable for years, which at a given moment starts to grow and change, and degenerates into melanoma.
With these clear concepts in mind we can better understand what a mole mapping with digital dermoscopy is and what it is for.
What is mole mapping?
It is the obtaining, in a systematized and ordered way, of a set of panoramic and dermoscopic images of most of our moles, which are archived to facilitate their subsequent surveillance.
The mapping can be partial if we limit ourselves to include the specific areas with the most moles (for example, the back) or total, in which we include almost the entire skin surface of the patient. Total mapping is more informative, as melanoma does not always appear where the patient had the most moles or the most atypical ones.
Who should have a mole mapping?
Mole mapping is especially indicated in people at higher risk for melanoma and/or more difficult to monitor. This includes patients with many moles and/or atypical moles, people with a personal and/or family history of melanoma, and people with fair skin, abundant freckles, blond or red hair, light eyes, difficulty tanning and easy sunburn.
How is it done?
We currently have modern digital dermoscopy equipment with high-definition imaging that allows us to take, archive and compare panoramic (sector) and dermoscopy (individual moles) images. Obviously, not all mapping is the same.
Factors to consider in the quality and accuracy of mapping are:
– The image quality of the equipment
– The dermatologist’s experience in image interpretation.
– The number of panoramic and dermoscopy images included.
A more exhaustive mapping is more time consuming but more informative for follow-up. I personally favor this option.
How often should it be repeated?
It depends on the patient’s risk profile and the type of moles they have. For most patients an annual check-up may be sufficient. In very high risk patients, check-ups every 6 to 9 months may be considered.
To facilitate the early detection of nodular melanomas, we should always facilitate an immediate check-up if the patient observes any new mole with rapid growth as well as changes or unwarranted discomfort in any mole.