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April 21, 2015 / molehunter

World Dermoscopy Congress-controversies part 1

This is part of a series of write ups of presentations I attended at the recent World Dermoscopy Congress at the Hofburg Palace, Vienna. With all these write ups, I am working from my contemporaneous notes, not a transcript, so I may have added some interpretation but have tried to report as accurately as possible. I am open to any corrections.

Scott Menzies (Australia) and Ashfaq Marghoob (USA) chaired a discussion on controversies in dermoscopy

kittler_4558

Professor Harald Kittler (photo from web) spoke on the metaphorical versus descriptive language. As he said, much of this was repetition from the consensus meeting that had taken place just before the start of the conference  on Thursday morning. There was not so much of a controversy any more.

The first dermoscopy consensus meeting had taken place in Hamburg in 1990, the next conference between experts of the International Dermoscopy Society (IDS) was run over the internet in 2003. The 2003 consensus was still pretty good, but since then the literature on dermoscopy had  grown exponentially, and at the same time the number of metaphorical terms introduced to denominate dermoscopic structures had also grown exponentially. He showed a chart of some of these terms, some sounded rather silly and at best ambiguous, although probably they made sense to the people who came up with them! I had to laugh as I have invented a couple of terms, ‘charcoal flecks’ for the thrombosed capillaries we see in resolving traumatised seborrhoiec keratoses and ‘raspberry and orange trifle’ for the micro-erosions on a pink background we see on some superficial spreading basal cell cancers.

Examples included the  ‘Mushroom cloud sign’, ‘mosaic like pattern’, ‘spermatozoa’ ‘bonbon toffee sign’, ‘dirt trails’. and ‘Barrel shaped areas.‘ Barrels seen and drawn from what angles, I wondered? Some terms, such as ‘ashy holes’ were even more obscure. Interestingly, none of the recently invented terms that were not found in the 2003 consensus document were in common and widespread use. This suggests that the leaders of 2003 got it right. However, the 2003 consensus was now in need of refinement.

As Professor Kittler said, the terms did not define themselves. In order to simplify the growing complexification of terminology, in  2007 he had proposed a descriptive terminology consisting of just 5 terms: lines, clods, dots, circles and pseudopods. Using just 5 nouns, with some adjectives to refine them such as (e.g. lines could be thick, curved, radial, parallel, shiny etc) or colours (e.g. clods could be yellow, red, white etc). Adding in spatial arrangements (e.g. central, eccentric, multiple, single etc) it should be possible to describe all known sub-macroscopic structures seen on dermoscopy in no more than 6 words.

Some of this is quite easy. For example, peppering becomes grey dots, lacunae in haemangiomas become red or blue clods, radial streaming becomes peripheral lines radial, the chrysalis sign/crystalline structures becomes shiny white lines.

He said ‘You can use these 5 basic terms to describe practically everything, so you don’t have to use metaphoric terms unless you want to. ‘ I appreciated the ‘practically’ and ‘unless you want to’. Following on from the very constructive discussion at the consensus meeting, it was made clear that where metaphorical terms were agreed and made sense, there would be no ‘1984 Newspeak’ tyranny against their use-although they needed to be pruned and defined-and please no more invented unless there was a clearly defined gain.

Misunderstandings were discussed. Firstly, the descriptive term is not the definition of the structure. The descriptive term may sound more like a definition but it is not-the definition of the description will come out in the dictionary which is to be published soon.

Also, it was made clear that descriptive language does not exclude the possibility of using metaphoric terms, since in fact terms like pseudopods and clods are metaphors. The difference is that they are limited in number and defined. He compared the metaphorical and descriptive language as being like Chinese compared with English language

On the subject of English versus Chinese, the point was made that all metaphoric terms can be translated into descriptive language and this will help colleagues share insights internationally through books, papers and other communications which will help put dermatoscopy on to a firmer scientific footing.

Sometimes with dermoscopy, like when we see a picture of an elephant, we ‘just know’ immediately. When you know the diagnosis you can use metaphors-however, this may mislead us into being more confident than we ought to be.

Advantages of the descriptive terminology is that it is simple, can describe everything, does not imply diagnosis, is easily translated into all global language and is independent of cultural baggage and assumptions e.g. elephants, maple leaf, tatami, spoke wheel.  Kittler also stated that some people claimed that t he descriptive terminology was difficult to learn, but he denied this was so and suggested that perhaps some people simply did not want to learn to use something different. I can see both sides of the argument as I learned dermoscopy from older books and teachers using metaphorical language.

Descriptive is more scientific and limits the development of new terms

However, metaphorical language has some advantages. We enjoy making and using these terms and that can be catchy, sometimes shorter. Some metaphoric terms are so good, and have been tested in use, so that we do not want to give them up. But the IDS survey showed that almost nobody switched from using descriptive to metaphoric language, while a growing number were switching from the old to the new. Most people still use both.

Professor Kittler finished his presentation with a quote from Aristotle

‘ To learn easily is pleasant, words signify something, and so whatever words create knowledge in us are the pleasantest.’

In conclusion, it seems clear to me that the arguments for moving to limit (although not totally exclude) the use of metaphorical terminology in dermoscopy and replace it with a simplified, definitively described, globally applicable, descriptive set of terms is gaining strength. It also seems likely that a tipping point will arrive when the new consensus is presently published in the form of a dictionary. I have already begun moving in this direction in the way I describe structures here, for example out with the chrysalis sign and in with shiny white streaks-or should that be shiny white lines?

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