35336 Do dermatologists realize a reliable clinical diagnosis of melanocytic nevi?

Abstract

Background: The presence of melanocytic nevi (MN) is due to the accumulation of melanocytes in the epidermis, dermis or both. A clinical-histopathologic concordance was sought in a previous study, where MN and other dermatoses were included, finding a global concordance of 64%. There is no previous literature of clinical-histopathologic concordance of MN in our population. Objective: To determine clinical-histopathologic concordance of MN, and to evaluate sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of clinical diagnosis of MN. Cross-sectional, observational and retrospective study from a registry of patients who requested medical care in an outpatient dermatology clinic. Patients who underwent biopsy during a 2-year period were included. We determined frequency and percentages of histopathologic findings from patients with a clinical diagnosis (by dermatologists) of MN. Sensitivity, specificity, PPV and NPV of clinical diagnosis was evaluated. Data were analyzed using the IBM SPSS Statistics program. From 102 biopsies, 41 were included; 68.3% of patients were women, mean age was 40.37 years, the most frequent topography was the head (82.9%). Diagnosis of MN was confirmed in 73.2% of biopsies. Lesions clinically confused with MN were mainly seborrheic keratoses (14.6%) and basal cell carcinomas (4.9%). Sensitivity of clinical diagnosis was 83.3%, specificity 83.3%, PPV 73% and NPV 90%. Conclusion: diagnosis of MN was confirmed by histopathology in 73.2%, a higher percentage when compared with previous literature. The diagnosis most frequently confused with MN was seborrheic keratosis. Our findings highlight the importance of the clinical diagnosis made by the dermatologist, which reached a sensitivity and specificity of 83.3% in this study.