Worrying mole on back
Reported as bleeding and itching (*) ‘mole’ on the back. Older white person with sun damaged skin. On paper that’s concerning.
On inspection the lesion is of mixed colour and looks angry with a red halo. How do we know it’s not a melanoma?
Let’s get the dermoscope out (in this case the Dermlite D1 that clips to my IPad mini, which I’m posting this on from a hotel in Birmingham where I’m staying for a PCDS education conference.)
‘CHAOS AND CLUES’
Harald Kittler asks the question ‘Is it chaotic? If yes, is it a seborrhoeic keratosis?’ This is a little chaotic, so we look for clues.
In the upper part of the lesion we see looped vessels of similar size and disposition. This is a clue to a keratinising lesion, most likely a seb k. Beware though as we may see radially arranged looped vessels in squamous cell cancers (SCCs). Does this look like an SCC? No, not solid or fleshy enough.
any other clues? Yes, there is brown pigment in the lower half. Is it lines or clods? A bit of both really. Broad lines curved is a fair description. The image quality isn’t fantastic. But I can’t see the dots, globules or reticular network we expect in a melanocytic lesion, more like a rough cerebriform pattern.
Other features include a very well defined rounded border and some white flakes of keratin at 5 and 10 o’clock. All this points to a seborrheic keratosis. I see no features pointing to a skin cancer.
(*) In my experience, most skin cancers don’t itch and most skin lesions that itch aren’t skin cancers. The feature of itch is therefore useless in diagnosis, regardless of the fact that a very few cancers present with itching. A skin lesion that presents with a story of recent itching and bleeding will nearly always be a seborrheic keratosis that had been scratched or caught on a bra strap.