Adding dermoscopy to the classic and modified melanoma ABCD criteria will help speed detection of melanoma in children, said Cristina Carrera, MD, of the University of Barcelona, and her associates.
Pediatric melanomas make up less than 3% of pediatric cancers and 1%-4% of all melanomas, occurring more commonly in adolescents than in children aged 5-9 years. These cancers often are thicker when first seen because of delay in diagnosis and/or differences in growth dynamics. Delay in diagnosis may occur because of the low incidence of pediatric melanoma and because classic melanoma criteria – ABCD: asymmetry, border irregularity, multiple colors, diameter (6 mm) – don’t always apply, they said.
A modified clinical ABCD rule of ‘‘amelanotic, bleeding bump, color uniformity, and de novo lesion of any diameter’’ was proposed to improve early detection of pediatric melanoma. And because dermoscopy improves melanoma diagnosis in adults, researchers decided to examine clinical and dermascopic findings in a group of pediatric melanoma cases.
Fifty-two pediatric melanoma cases from 51 patients were collected from pigmented lesion clinics across nine countries (Australia, Belgium, Brazil, France, Israel, Italy, Serbia, Spain, and the United States), and clinical and dermoscopic specimens were examined by two experienced reviewers.
The mean age of the patients was 15 years, and 26 of the patients were female. Histopathologically, 28% of the pediatric melanomas were classified as spitzoid and 72% as nonspitzoid. Patients with a spitzoid melanoma were significantly younger than those with nonspitzoid melanoma (12.5 vs. 16 years, P = .004). All of the spitzoid tumors were invasive, and they were significantly thicker than the nonspitzoid melanomas (2.6 vs. 1.2 mm, P = .004). Also, these lesions more frequently were ulcerated than nonspitzoid melanomas (29% vs. 8%, P = .06). Melanomas associated with a nevus more often were among nonspitzoid than spitzoid melanomas (62% vs. 27% P = .02), and the congenital type of nevus was linked most often with nonspitzoid melanomas (25 of 27 [92.6%]), Dr. Carrera and her associates reported.
The pediatric melanomas in this study appeared most frequently on the lower extremities (31%), followed by the back (27%). Spitzoid melanomas most often appeared on the limbs (73%); nonspitzoid melanomas were likely to occur on the torso (52%).
In the majority of cases (52%), the overall clinical morphology was considered to fulfill the classic melanoma ABCD criteria. The remaining lesions that did not fulfill the conventional ABCD criteria were called benign-appearing tumors or nodular/polypoid tumors. Spitzoid melanomas most often were nodular/ polypoid (47%), while most nonspitzoid melanomas (59%) were melanoma-like. Only 21% of the pediatric melanomas fulfilled the modified melanoma ABCD criteria, they noted.
On dermoscopy, which was available in 49 cases, a multicomponent pattern seen in 24 cases mostly was associated with nonspitzoid melanoma (88%, P less than.03); a nevus-like pattern in 9 cases was seen only among nonspitzoid melanomas. A vascular pink Spitz-like pattern in seven cases mostly was associated with spitzoid melanomas (86%, P less than .002). A pigmented Reed-like pattern seen in seven cases occurred more often among spitzoid melanomas, but this did not reach statistical significance, the investigators wrote.
In terms of appearance, “red and white colors, milky red areas, polymorphous vessels, and shiny white structures were associated with spitzoid melanoma. Dark brown color, atypical network, and structureless areas were associated with nonspitzoid melanomas,” Dr. Carrera and her associates said.
Dermoscopic patterns that were pink spitzoid or Reed-like were more likely to be histopathologically classified as spitzoid. These pediatric melanomas were linked with younger age, occurrence on the limbs, and de novo development. On the other hand, dermoscopic patterns that were multicomponent or nevus-like were likely to be histopathologically classified as nonspitzoid. These lesions were linked with older age, fair skin phenotype, family history of melanoma, and a preexisting nevus, the researchers said.
“In contrast to previous reports, the present study highlights the fact that the majority of melanomas diagnosed in patients younger than 20 years look similar to melanomas found in adults. Nonspitzoid melanomas were associated with adolescence and with the presence of melanoma risk factors. All nonspitzoid melanomas displayed dermoscopic features associated with melanoma. Spitzoid melanomas were associated with younger age, location on the extremities, and nodular/polypoid clinical morphology. Dermoscopy of spitzoid melanomas revealed atypical vessels and shiny white lines (if amelanotic) or an asymmetric starburst pattern (if pigmented),” Dr. Carrera and her associates concluded.
The investigators had no relevant financial disclosures. The study was supported in part through a grant from the National Institutes of Health/ National Cancer Institute. The research at the melanoma unit in Barcelona was partially funded by grants from the Spanish Fondo de Investigaciones Sanitarias and CIBER de Enfermedades Raras of the Instituto de Salud Carlos III, Spain; it was confinanced by numerous other grants.
SOURCE: Carrera C et al. J Am Acad Dermatol. 2018;78(2):278-88. doi: 10.1016/j.jaad.2017.09.065.