The prevention, diagnosis, referral and management of melanoma of the skin: concise guidelines

Melanoma of the skin is an increasingly common tumour, which often has a slow early growth rate during which curable lesions may be detected and removed. Physicians therefore have the potential to reduce mortality and this guideline is intended to promote early diagnosis of melanoma. The majority of melanomas occur in white-skinned people. The most common risk factors are pale sun-sensitive skin and the presence of increased numbers of melanocytic naevi (moles). Melanoma is more common in women than men; the mean age of onset is 50 years; and a fifth of cases occur in young adults. In the UK population the most common sites are on the lower leg in women, and on the back in men. The predictors of melanoma are progressive change in the shape, size and colour of moles. This guideline provides a series of photographs of moles, melanomas and other skin lesions, which may resemble melanomas.

Histopathological characteristics of small diameter melanocytic naevi

BACKGROUND/AIMS

The clinical definition of an atypical naevus ("dysplastic naevus" or "naevus with architectural disorder and cytological atypia of melanocytes") stresses size larger than 5 mm in diameter as a major diagnostic criterion. Because malignant melanomas and their precursors may arise in smaller lesions, a histological study of melanocytic lesions smaller than 4 mm in diameter was conducted to evaluate their histological appearance.

METHODS

Two hundred and sixty one naevi smaller than 4 mm in diameter were collected and characterised by histological examination into benign naevi without architectural disorder and naevi with architectural disorder and mild, moderate, and severe atypical melanocytes according to criteria used on larger lesions.

RESULTS

Small melanocytic naevi covered the same complex histological spectrum from benign naevi to severely atypical naevi when compared with larger lesions. A high proportion of small naevi (72%) exhibited features diagnostic for naevi with architectural disorder and cytological atypia.

CONCLUSION

There is a discrepancy between histological and clinically defined atypical naevi. The same generally accepted criteria for the histological diagnosis of atypical naevi should be used for small melanocytic naevi in addition to large ones. Thus, small naevi exhibiting atypical features on histological examination should be categorised as atypical naevi, regardless of their small diameter.