fingerprints in a flat benign skin lesion

This skin lesion was referred as the older white patient was anxious about it.

6mm diameter, flat, even colour, more or less round, edge pretty even. Not much to get excited about. Apply dermoscope.

The innocence of this lesion is made even clearer on dermoscopy. Trivial variation of shade of brown is of no consequence.  There is no colour here other than light to medium brown. As to pattern, there are some circles near the centre, but on the left and between about 4 and 7 o’clock we can see a fingerprint sort of pattern, otherwise termed broad parallel lines. There are NO dots, no globules, no streaks, no blue grey veil and no additional colours. We cannot make this a lentigo maligna, not even close.

This is either a benign solar lentigo or a flat seborrhoiec keratosis. Even the top experts cannot tell between these 2 common flat, brown skin lesions often seen in older white people. It doesn’t matter, since both are equally harmless. The patient can be reassured, and perhaps while they are thinking about potentially worrying moles given a short tutorial on what dangerous moles look like. I talk them through a collection of a dozen images of melanomas downloaded from the web that I keep on my tablet for this purpose (I used to use my Galaxy big screen mobile phone, but the tablet does the job better). People usually follow this with some interest. I think this is a good way to spend 2 or 3 minutes out of a 15 minute consultation when the presenting skin lesion is so obviously harmless the doctor doesn’t need to spend much time on it. Perhaps a little tutorial on melanoma recognition may save a life later by educating just one person about what a dangerous mole looks like.