Reliability of the Histopathologic Diagnosis of Malignant Melanoma in Childhood

OBJECTIVE: To assess interrater reliability in the diagnosis of malignant melanoma in children. DESIGN, SETTING, AND PARTICIPANTS: We collected 85 slides of melanomas diagnosed in patients younger than 17 years through a network of dermatopathologists and dermatologists. The slides were classified into 3 categories: (1) slides from children with metastatic melanoma; (2) slides from disease-free children with a follow-up of less than 5 years; (3) slides from disease-free children with a follow-up of 5 years or longer. Category 1 was considered the gold standard. Four pairs of expert dermatopathologists reviewed the slides and classified them into melanoma, nevus (including Spitz nevus), or ambiguous tumors. INTERVENTION: None. MAIN OUTCOME MEASURE: Concordance between pairs of experts. RESULTS: For category 1 slides (n = 20), the concordance was weak to moderate. For category 2 slides (n = 47), the concordance was weak. For category 3 slides (n = 18), the concordance was poor to moderate. CONCLUSION: This study demonstrates that the reliability of diagnosis of melanoma in childhood is poor, even when submitted to experts.