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April 22, 2015 / molehunter

a bland skin lesion

Most skin lesions that present to the doctor or practice nurse are harmless. This is the most fundamental fact of dermoscopy. Obviously dangerous skin lesions, notably melanomas, do exist or we wouldn’t be having this discussion, but they are relatively uncommon. But most times (way over 90% of the time) when we as clinicians are asked to see a patient who is ‘worried about a mole’ our job will be to safely diagnose it as harmless and reassure and advise.

case 15  A

This lesion on an older white man’s face had caused sufficient anxiety for them to seek medical advice. It had been growing over the recent year or so. On plain examination it appears to be a fairly even light to medium brown colour. a fissure is just visible running down from around 12 o’clock. To my trained eye, it looks like a seborrhoiec keratosis. Dermoscopy further refines the diagnosis.

As usual, left click on the image to enlarge.

case 15  B

Dermoscopy confirms the evenness of colour. As to structures, we see numerous pale circles of even size, mainly evenly located throughout the lesion. This is normal pseudonetwork (*). Interestingly, the pale circles are absent from a central area just below the mid line (circled in image below), where instead we see more solid looking and smaller brown clods. This fits with a seborrhoiec keratosis which is developing from flat to elevated, as they naturally tend to do over time.

case 15  B  - Copy

The pale circles represent adnexal gland openings, either sweat ducts or hair follicles. Pigment ‘flows’ around them. Where they are absent just below the middle of the lesion, the keratosis has grown thicker so they are no longer seen.

This is a developing seb k, couldn’t be anything else. No apologies for posting images of banal lesions that are (or should be) immediately recognisable as harmless. As we heard at the Dermoscopy World Congress in Vienna last week, skin cancer and the fear of it is rising steadily world wide, dermatology services are under significant pressure, so it is necessary to train Primary Care based health workers (doctors and nurses) to screen out the mass of lesions which are benign. This isn’t happening as well as it might do.

(*) pseudonetwork is one of the metaphorical terms (see last posting) which is too good to lose. It has a very specific meaning once you know, and is short and memorable. In the Kittlerian terminology I suppose it would be ‘pale circles on facial skin surrounded by pigment’. Perhaps using both sets of terms while defining the metaphorical terms more rigorously as is proposed by the International Dermoscopy Society will help us to triangulate our thinking and ‘mean what we say and say what we mean’ more consistently.


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