Pediatric Melanonychia: When to Recommend Biopsy or Excision

Conclusions

• Most pediatric longitudinal melanonychia is caused by benign melanocytic lesions such as nail matrix nevi, while melanoma remains rare.
• The diagnostic approach should be age-stratified because benign and secondary causes differ by age, with younger children more often showing benign lesions and older children more often showing secondary causes.
• Many classic adult warning signs, including wide bands, irregular pigmentation, triangular patterns, and Hutchinson sign, are less specific in children and do not automatically indicate melanoma.
• Some features that appear alarming in children can regress over time, suggesting that pediatric nail pigmentation can follow a dynamic and sometimes self-limited course.
• Hutchinson sign in children may reflect benign longitudinal brush pigmentation rather than melanoma, so it requires careful interpretation rather than immediate assumption of malignancy.
• Biopsy should be reserved for cases with rapid change, progressive atypical features, or persistent concern, especially in older children.
• Clinical monitoring is appropriate for reassuring cases, but shared decision-making is important because biopsy can reduce anxiety and provide a definitive diagnosis.
• When performed well in selected cases, nail matrix biopsy can yield both diagnostic clarity and acceptable cosmetic outcomes.