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December 11, 2015 / molehunter

asymmetrical melanoma on dermoscopy

I posted this lesion earlier, this is a look from a different angle to make a point about a couple of diagnostic algorithms.


If we apply the 2 step algorithm, we find

  1. it is melanocytic, because we see reticular network, also brown globules, either of which are characteristic of melanocytic naevi. Also, it is melanocytic by default since there are no clues allowing us to positively identify another type of skin lesion, e.g. seborrhoiec keratosis, haemangioma, BCC etc.
  2. if melanocytic (which it is-see above) could it be a melanoma? Or to ask the same question in a different way, can we say with confidence that it is benign? The answer is, no we can’t prove its benign because it is very irregular-both pattern and colour evidence significant lack of symmetry.

We must therefore excise as a suspected melanoma.


If we apply the Harald Kittler ‘chaos and clues’ algorithm we get the same answer by a different route.

  1. Is the lesion chaotic? (Kittler defines chaotic as more than one pattern and/or more than one colour. However, there are degrees of chaos between zero and complete and utter chaos, we get a feel for evaluating degrees of chaos by studying hundreds of lesions). Anyway, we see structureless areas plus lines reticular and clods, also at least 3 colours, so yes it’s chaotic.
  2. Since chaotic, look for clues. I have already mentioned clues to melanocytic, and no clues to anything else, so by the Kittler method we now have a chaotic melanocytic lesion, which by definition must be excised.


Histology confirmed a thin (therefore eminently curable) melanoma.



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