ON NEVI AND MELANOMAS IN DYSPLASTIC NEVUS SYNDROME PATIENTS

Cutaneous melanoma may occur as isolated, so-called 'sporadic' cases o r in association with multiple atyical naevi and in familial clusters, in which case it is referred to as the familial dysplastic naevus syn drome (DNS). In this retrospective study (a) the number and body distr ibution of naevocytic naevi and (b) the body distribution of malignant melanoma (MM) in individuals with familial DNS were compared in order to study their association. In 45 patients with familial DNS aged 20- 39 years naevus counts on trunk and lower extremities were compared wi th melanoma data and distributions from a second group of 43 patients from the same DNS families aged 12-66 years. Men had significantly mor e naevi of a size greater-than-or-equal-to 2 mm or greater-than-or-equ al-to 5 mm on the back than women (P=0.02). Women showed a tendency to wards a greater number of naevi on the lower extremities than men, but in women no significant difference in naevi between the lower extremi ties and the back was found. The total number of naevi on the trunk an d lower extremities in familial DNS patients was higher than that in t he general population. In conclusion, it was found that predilection s ites for melanoma in familial DNS patients of both sexes correspond wi th the distribution of naevi; in males naevi and melanoma counts and p ercentage distributions were higher on the back, in females both the b ack and the lower extremities were affected. These findings strongly s uggest an association between naevus distribution and melanoma occurre nce and site in familial DNS, analogous to earlier reports on sporadic melanoma.1,2