An Alternative Diagnostic Algorithm for Detecting Pediatric Melanomas

Graeme M. Lipper, MD

Jul 08, 2013

Pediatric Melanoma: Results of a Large Cohort Study and Proposal for Modified ABCD Detection Criteria for Children

Cordoro KM, Gupta D, Frieden IJ, McCalmont T, Kashani-Sabet M

J Am Acad Dermatol. 2013;68:913-925

Study Summary

Pediatric melanomas are rare, with patients younger than 20 years of age accounting for 2% of reported melanomas and prepubertal children accounting for only 0.4%.^[1] Unfortunately, juvenile melanoma may be misdiagnosed due to a low index of suspicion, absence of conventional ABCDE diagnostic criteria (Asymmetry, Border irregularity, Color variegation, Diameter > 6 mm, Enlarging lesion) and ambiguous histopathology.^[2-4] Is there a better diagnostic algorithm for detecting pediatric melanomas?

To address this question, Cordoro and colleagues looked at a cohort of children (< 20 years old) diagnosed with melanoma (N = 60) or ambiguous melanocytic tumors treated as melanoma (N = 10) over a 25-year period of time. These 70 patients were further subdivided into 2 groups: Group A (prepubertal, 0-10 years old, n = 19) and Group B (pubertal, 11-19 years old, n = 51).

Cordoro and colleagues analyzed these pediatric melanoma cases for demographic characteristics, primary lesion characteristics, histopathological characteristics, prevalence of sentinel lymph node and distant metastases, molecular features, melanoma staging, and survival. They made the following main observations:

1. Sixty percent of prepubertal melanomas (Group A) and 40% of melanomas presenting near or during puberty (Group B) lacked conventional ABCDE criteria.
2. Clinical features associated with pediatric melanomas included: amelanosis, bleeding, "bumps" (nodularity), uniform color, variable diameter, and de novo development.
3. The majority of prepubertal melanomas were amelanotic (76%).
4. Almost 100% of pediatric melanomas presented with growing ("evolving" or "enlarging") lesions.
5. Forty-four percent of these pediatric melanomas could not be histopathologically classified into a current melanoma subtype. Most pediatric melanomas showed nodular, spitzoid, or "unclassifiable" histopathological features.
6. Clinically, pediatric melanomas presented at a more advanced stage and behaved more aggressively than melanomas presenting in adults.
7. Melanoma risk factors are similar for children and adults (family history of melanoma, dysplastic or numerous melanocytic nevi, immunosuppression, xeroderma pigmentosum).

Viewpoint

This retrospective cohort study confirms that conventional ABCDE criteria will fail to detect pediatric melanomas in a majority of cases, especially in prepubertal children. In contrast, Cordoro and colleagues proposed an alternative set of ABCD criteria for children: Amelanotic bleeding, "Bump," Color uniformity, De novo appearance, any diameter.

In children under 10 years of age, most melanomas were amelanotic and presented as rapidly enlarging nodules, so lesions presenting with these features should be treated as highly suspicious. It should also be noted that most pediatric melanomas, at least in this cohort, presented with nodular, Spitzoid, or unclassifiable histopathology. In this context, dermatopathologists should be aware that melanomas in this age group may be challenging to diagnose and often do not fit conventional melanoma subtypes (superficial spreading, nodular, acral lentiginous).