Diagnosis of the dysplastic nevus in different populations

Because of the relationship of the dysplastic nevus to melanoma, physicians are being encouraged to identify the clinical features of this newly defined entity. However, the dysplastic nevus was originally characterized in the familial setting, and application of equivalent criteria to the general population will be disappointing. The ability of the clinician to diagnose the presence of dysplastic nevi will be markedly influenced by the true underlying prevalence of dysplastic nevi in the population subjected to the examination. Even with superlative (and perhaps unattainable) examining skills (e.g., sensitivity and specificity both 90%), the positive predictive value in the general population will be relatively low (less than one third). Grading the severity of clinical dysplasia, obtaining serial observations, and improving specificity of clinical examination are important but irrelevant to this problem because these items focus only on examining skills. Consideration given to the epidemiologic and referral characteristics of the person undergoing examination will substantially improve the ability to predict dysplastic nevi on clinical evaluation. Although comprehensive recommendations must await further research, some priorities in the diagnosis and management of patients with presumptive dysplastic nevi are suggested.