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June 14, 2012 / molehunter

Dermoscopy is a waste of time

…for lesions like this.

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A fast growing, often tender nodule on a sun exposed area like the back of the hand or bald scalp of an older white man is a squamous cell cancer (SCC) until proved otherwise. The hard keratin top makes the diagnosis very likely in this case. Not all SCCs produce keratin horn, but most fast growing keratinised tumours will be SCCs. They are also seen on ears and over the shin, especially in older white females. These cancers rarely spread but it can happen. New, Firm and Growing (NFG) skin lumps require investigation in any site or age group.

Dermoscopy is of little to no value for such lesions. The diagnosis is made on history and inspection. The enthusiasts for dermoscopy (of whom I am one) need to be realistic about its limitations if we expect to be taken seriously. There is no point teaching dermoscopy skills to doctors or nurses who don’t first of all understand basic things about the natural history of skin cancer and skin lesion recognition.

Some dermoscopists say there are certain diagnostic features that can be seen in these lesions, for example hairpin vessels, but I am unconvinced.

A squamous cell cancer like this is nearly always curable, but needs urgent excision. SCCs can spread if neglected. Cryotherapy or curretage and cautery are not good enough. The dermoscope is no use at all for diagnosing this kind of lesion, and is quite uneccessary.

PS a keratin forming nodular lesion of this sort is sometimes a keratoacanthoma. These are benign lesions that mimic squamous cell cancer, but are harmless and often fall off spontaneously. However, the modern consensus is to refer all suspected keratoacanthomas for urgent removal as even top experts can’t tell the difference reliably. I concur with this wise approach.

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  1. Adrian Bowling / Jun 18 2012 3:52 am

    So true. In fact dermoscopy may mask what is really going on with a lesion. That is why in our MoleMap/MoleSafe program our nurses are taught firstly about skin cancer and then dermoscopy and they always take a clinical and dermsocopy view of the lesions and record relevant history for telediagnosis by a dermatologist. I like the NFG acronym.

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