Another ugly duckling on the back
This middle aged white man has a stand-out pigmented lesion on his back to which the eye is drawn as it looks completely different from any other lesion we can see on his skin. This is the single most useful diagnostic feature of skin cancers including melanoma-the ‘ugly duckling’. Never neglect an ugly duckling.
So naturally we want to take a closer look with the dermoscope.
We see clear cut features of a seborrhoiec keratosis. the patient can be confidently reassured and no treatment is necessary.
the third image outlines the typical features. the three largest comedo like openings (keratin pits) are circled, 2 arrows point to milia-like cysts (not the most prominent examples of milia like cysts in my image collection but clear) and the very clean stuck-on edge is outlined. the keen dermoscopists can also pick out some ‘frogspawn’ i.e. tiny looped vessels in papillae. These are not so easy to see, but I can see them and they add to the level of confidence. It should also be noted that there are no signs of a BCC, haemangioma or a melanocytic lesion (see other posts for discussion of what these signs are).
So, the ugly duckling sign is a good pointer to a melanoma, but very often an ugly duckling will be a ‘sheep in wolf’s clothing’, a harmless skin lesion that looks worrying The dermoscope can relieve anxiety by finding positive signs of a benign lesion, as in this case. Skilled dermoscopy can screen out lesions like this at the first consultation, avoiding the cost and anxiety of an urgent skin cancer referral.