Twenty nevi on the arms: a simple rule to identify patients younger than 50 years of age at higher risk for melanoma

Patients with a high total nevus count (TNC) merit a total-body examination, but a simple strategy to identify these high-risk individuals is essentially missing. The aim of this study was to investigate the correlation between the number of melanocytic nevi on both arms and the TNC, and to evaluate patient variables that may have an effect on this association. In this multicenter, cross-sectional study, 2175 patients were examined and the mean number of arm nevi in relation to TNC was calculated. A mean value of fewer than 10 arm nevi was found in patients with TNC lower than 51 and a mean value of greater than 19 arm nevi was scored in patients with TNC greater than 50. These values remained unchanged after adjustment for various patient variables. In relation to TNC greater than 50, the presence of 20 or more arm nevi had specificity and negative predictive values of 95.2 and 89.6%, respectively. The sensitivity was 65.5% in patients younger than 50 years of age and 37.5% in the older age group. The number of arm nevi was significantly higher in individuals with a history of melanoma and in those with a melanoma detected during the study period. The presence of 20 or more nevi on the arms is an independent predictor of a high TNC and risk of melanoma. This sign thus represents a simple and rapid screening tool for either the primary care physician or the dermatologist to help identify high-risk patients