ARE BIRTHMARKS A CANCER?
Most of us probably try quite hard not to think about cancer, at least in a personal sense. Even so, almost all of us will have given it a moment’s thought when contemplating the various birthmarks, moles and warts that adorn most human bodies. The thought will have come as two questions: are these cancers and what should I do about them? To which the answers are ‘no’ and ‘nothing’ – almost always. In a strictly technical sense, they are indeed neoplasms because they are an abnormal growth of skin but the best thing to do is simply regard them as a blemish. Some birthmarks, for example, strawberry marks that generally occur on the face, gradually disappear of their own accord. For marks that do not and are felt to be disfiguring it may be possible to reduce their prominence by laser treatment. But there is just one word of warning – hidden in the ‘almost always’ above. The medical fraternity refers to birthmarks as naevi, the most common naevus being composed of melanocytes, melanin-producing cells in the bottom layer of the epidermis. Thus moles are benign tumours formed from clusters of pigmented skin cells. The only real problem with moles is that just occasionally one of them may turn nasty and develop into a fully malignant tumour but there are two reasons why even this should not keep you awake at night. Firstly, that event usually needs some help from you – something that large numbers of us provide by lying in the sun without any protection. Secondly, because these are skin growths you should notice any change in their behaviour; which is: why you are advised to use sun creams and to take action if any of your moles change appearance – get bigger, blacker or itchier or start bleeding.
Warts have much in common with birthmarks and moles but there is one big difference: warts are caused by viral infection. For that reason, we aren’t born with them and indeed they are rare in babies. Nevertheless, most of us get them at some point, often before we are twenty. A recent survey of children in the UK revealed that almost all of them had warts of some description. Fortunately, almost all warts are harmless and disappear of their own accord – though some take years to do so. Warts are rough lumps of skin that commonly arise on the hands or feet or in the anogenital area. Palmar warts occur on the palm of the hand, plantar warts, otherwise known as verrucas (verruca plantaris), on the soles of the feet. Warts are contagious because of their viral cause, the virus in question being human papillomavirus (HPV). There are more than 100 types of HPV, different types causing different wart variants. HPV produces warts because it causes cells in the top layer of skin (epidermis) to make excessive amounts of the protein keratin. Although it is not possible to get rid of HPV once infected, most warts can be treated either chemically or by either freezing (cryosurgery), burning (cauterisation) or by laser treatment.