Pediatric melanoma: A wolf in sheep’s clothing
Sept. 27, 2016
Despite its rarity, the incidence of pediatric melanoma (PM) has been increasing. Every practicing dermatologist, past or present, has been humbled or fooled by the clinical appearance of melanomas, examples being amelanotic or desmoplastic variants.
The A (asymmetry), B (border irregularity), C (color variegation), D (diameter > 6mm) and E (evolution) are have become ingrained in our professional lexicon, and the utilization of “ABCDE” screening for melanoma, either by physicians or patients, has undoubtedly saved many lives. Like any tool, it is not perfect for every circumstance — this is especially true for PM.
In their seminal paper, Cordoro et al performed 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. 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. 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 (i.e, large congenital melanocytic nevi, sun sensitivity, family history of melanoma, xeroderma pigmentosum, immunosuppression, or history of malignancy). Breslow thickness predicted metastasis (adjusted odds ratio 12.8 [CI 1.4-115]). The authors concluded that 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, especially in younger children (1).
These findings have been corroborated by Mitkov et al, who retrospectively analyzed records of children and young adults 21 years of age or younger with a diagnosis of primary cutaneous melanoma. Ninety-six PMs from 86 patients were included. Pediatric melanomas that mimicked benign skin lesions were more often deeper (>1 mm; odds ratio 5.48; P = .002) and had a higher T stage (odds ratio [T2, T3, or T4] 6.28; P = .001) than melanomas with a clinically malignant appearance. Of pediatric melanomas, 66% originally diagnosed as benign melanocytic lesions exhibited changes in size, shape, and color. The authors concluded that “benign-appearing pediatric skin lesions with a history of evolution, bleeding, or ulceration should raise suspicion for melanoma. Melanomas demonstrating these features are associated with a higher Breslow depth and T stage. Although biopsy of all lesions that exhibit change in children is not practical, safe, or desired, close monitoring is recommended.” (2)
Both papers emphasize the importance of “E”, in the classic ABCDE or the modified ABCDE for PM. (I have never been Enamored by “E”. By definition, evolution represents a slow change — as we will discuss momentarily, nevi change their appearance during their lifecycle. Perhaps a better term would be rEvolution, or just use “C” for color variegation and/or change).
The Study of Nevi in Children (SONIC) project emphasized that it is essential the normal changes in nevi be differentiated from abnormal changes. For example, nevi displaying globular or peripheral patterns in children would not be disconcerting, but those dematoscopic presentations would be highly suspicious for melanoma in an adult (3).
For those of us who see children, perhaps the best lesson is to listen to the history rather than dwell on how the lesion looks. As the biologic behavior of PMs, including death, belies a banal presentation, any lesion with either ABCDE criteria — classic or modified — warrants our utmost attention and concern.
1. Cordoro KM, et al. Pediatric melanoma: Results of a large cohort study and proposal for modified ABCD detection criteria for children. J Am Acad Dermatol 2013; 68: 913-25.
2. Mitkov M, et al. Pediatric melanomas often mimic benign skin lesions: A retrospective study. J Am Acad Dermatol 2016; 75: 706-11.
3. Scope A, et al. The study of nevi in children. Principles learned and implications for melanoma diagnosis. J Am Acad Dermatol 2016; 75: 813-23.
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