WCCS 2016

Skin cancer lesions arising in uncommon regions

Dr Josep Malvehy - University Hospital Clinic of Barcelona, Barcelona, Spain

I was talking about diagnosis in skin cancer and particularly in melanoma in special anatomic sites where lesions are really different from other general sites like trunk or limbs. So I was explaining the criteria for the early diagnosis of melanoma on the face and in acral sites.

How can you tell the difference between these sites?

In these particular sites dermatologists may have some challenges in the recognition of early melanoma. For that reason it’s very essential to distinguish particular criteria that have been refined during the last years. Using dermoscopy you achieve a better accuracy in that diagnosis. So we are explaining to the audience how to recognise these lesions that sometimes are very subtle according to the diagnostic features we use in our daily practice. These are what we call silver network and then blue/grey dots. We can see rhomboidal structures, atypical pigmentation of the follicular openings in these lesions particularly, this is very specific, and also the what we call a circle within the circle that is again the invasion of hair follicles by the melanoma. Finally we explain that when the melanoma progresses then you have the destruction of all the anatomy in the skin.

Particularly in amelanotic melanoma in these sites it’s sometimes very subtle to distinguish these criteria so it’s very essential that the doctors are looking properly at these lesions otherwise they can be misdiagnosed and they can wrongly be treated with cryotherapy or some other procedures that are wrong at all.

I was also in this lecture explaining the criteria in another most eccentric site in the body that is in acral sites. In particular in skin, this means in palms and soles, acral melanoma is very different from some other sites because of the particular anatomic structure of the skin. It’s very clear that acral melanoma is many times misdiagnosed by the doctors and this is because this can be misdiagnosed as a common wart or just some other lesions that are benign and because of this we have thicker tumours, thicker melanomas in these sites. It’s because of that that it’s very important to recognise the specific criteria for diagnosis in acral lentiginous melanoma where you can see what we call a parallel reach pattern, what we call diffuse pigmentation and sometimes, of course, with the progression of the tumour you will see many other criteria. Unfortunately many of these tumours are ulcerated and they arrive to their final treatment very late having in their time where the first consultation was done at early stages a long time with delay. For that reason we have to stress the recognition of these early tumours.

It’s very important and very relevant to understand that in acral lentiginous melanoma 10-20% of the tumours are amelanotic again so they don’t have pigmentation. In these situations we have real challenges if we are not able to recognise the vascularisation of the tumour, that is very, very important. Many times these tumours are treated like, again, warts, infections, disease or some other particular situation even like ulcers that are not healing for a long time. This is really devastating the prognosis of the patient in the end.

What can clinicians do to become more aware of these different sites?

I think that every clinician dealing with skin cancer, even if they are not experts within this topic, should understand and should recognise dermoscopic criteria in these particular sites. For that we have several opportunities in vocational meetings, also in workshops and courses.

Any final thoughts?

The many faces of melanoma are challenging for daily practice. Even if in the hands of very expert dermatologists sometimes they are very difficult to be recognised. Otherwise today we have tools that can be used to do a very good job in the early detection of melanoma and this can have the opportunity to save many lives in the future.