Background: Clinical and histopathologic features of childhood melanoma are poorly characterized. Atypical clinical presentations and ambiguous microscopic findings may contribute to diagnostic delays.

Objectives: We sought to determine whether conventional ABCDE melanoma detection criteria (Asymmetry, Border irregularity, Color variegation, Diameter >6 mm, Evolution [any morphologic or symptomatic change in the lesion]) adequately detects pediatric melanoma and to evaluate clinicopathologic and outcome differences between younger and older children.

Methods: This was a retrospective study of children given the diagnosis of melanoma (N = 60) or ambiguous melanocytic tumors treated as melanoma (N = 10) before age 20 years from 1984 to 2009 at the University of California, San Francisco. Seventy patients were divided into 2 age groups: 0 to 10 years (N = 19, group A) and 11 to 19 years (N = 51, group B). Clinical, histopathologic, and outcomes data were collected. Main outcome measures were time from diagnosis to death and predictors of metastasis and death.

Results: In all, 60% of group A and 40% of group B children did not present with conventional ABCDE criteria. Rather, amelanosis, bleeding, "bumps," uniform color, variable diameter, and de novo development were most common. Histopathological subtypes differed significantly between groups (P = .002). In all, 44% were histopathologically unclassifiable using current melanoma subtypes. Stage IIA disease or higher comprised 92% and 46% of groups A and B, respectively (P = .05). Ten patients died: 1 in group A and 9 in group B. Of these, 70% had amelanotic lesions, and 60% had at least 1 major risk factor. Breslow thickness predicted metastasis (adjusted odds ratio 12.8 [CI 1.4-115]).

Limitations: The retrospective design resulted in incomplete data capture.

Conclusion: Additional ABCD detection criteria (Amelanotic; Bleeding, Bump; Color uniformity; De novo, any Diameter) used together with conventional ABCDE criteria may facilitate earlier recognition and treatment of melanoma in children.