Suspicious but harmless mole
A mole on a white adult’s trunk gave rise to concern and was seen urgently. The specialist didn’t much like the look of it.
This lesion violates several of the ABCD rules, being Asymmetrical, irregular Border and mixed Colour. Diameter was just on 6mm, not very impressive (but as we know, size is relatively unimportant in appraising suspicious moles since you can have a 3mm melanoma or a 25mm benign skin lesion). Dermoscopy is clearly required.
Not VERY dramatic, but questionable. I can see 2 colours (pink and brown…maybe a touch of grey?) and 2 patterns (amorphous and globular). The globules are distributed asymmetrically, a few at the 9 o’clock apex and a cluster around 12 o’clock. Most of the top experts I heard teach at the World Congress in Vienna last April took a similar view-if someone has a large number of slightly worrying naevi, digital monitoring is good, but why lose sleep (patient and doctor) over a solitary odd lesion? Into the jar it accordingly went.
Histology was dysplastic naevus. As discussed (see earlier post linking to Harald Kittler’s presentation ‘The myth of dysplastic naevi’ there is a lot we don’t know about dysplastic naevi. In plain English, they are ‘funny looking moles’ (funny peculiar, not funny amusing) on plain view, on dermoscopy, and under the microscope, but they are not malignant. Maybe some of them will go bad, but we don’t know this. Is it a failure then when we excise one?
As I see it, if we are being careful with our patients’ safety, we will most certainly end up excising a proportion of dysplastic naevi, because we cannot reliably distinguish them from melanoma in situ or even some thin melanomas. Dermoscopy very often enables us to safely reassure a patient over a suspicious mole, but let’s be careful and not try to be too clever.