A clinical, histopathologic, and outcome study of melanonychia striata in childhood

Background The current literature suggests that approximately 5% to 10% of melanonychia striata cases in adults are the result of subungual melanoma. Objective We sought to evaluate the clinical and histopathologic features and to determine the outcomes and causes of melanonychia striata in a cohort of children. Methods We assessed 30 childhood cases of melanonychia striata for features typically associated with melanoma such as Hutchinson sign, width of the pigmented band, evolution, color, and nail dystrophy. We assessed the histopathology of lesional biopsy specimens, including melanocyte counts and suprabasal movement of melanocytes. Clinical follow-up information was reviewed when available. Results Histopathologic diagnoses included subungual lentigo in 20 cases, subungual nevus in 5 cases, and atypical melanocytic hyperplasia in 5 cases. Although a number of cases exhibited worrisome clinical or histopathologic features, none showed evidence of aggressive behavior or warranted a diagnosis of melanoma. Limitations The sample size and follow-up times are limited. Conclusions Melanonychia striata is typically associated with benign stable melanocytic proliferations in childhood. The overwhelming majority of cases can be managed conservatively. Biopsy is required in select cases.