results of a retrospective multicenter study showed.
Elena B. Hawryluk, MD
“The most striking thing that we learned from this study is that pediatric melanoma can present in so many different ways, and it’s distinct from the adult population in that we see more presentations associated with congenital nevi, or spitz melanoma, which is a special class of pigmented lesions that looks a little different under the microscope,” Elena B. Hawryluk, MD, PhD, of the department of dermatology at Massachusetts General Hospital (MGH) and Harvard University, Boston, said in an interview. Dr. Hawryluk is lead author of the study, which was published online ahead of print in the Journal of the American Academy of Dermatology.
Dr. Hawryluk and colleagues at MGH and 11 other centers conducted a retrospective review of all cases of fatal pediatric melanoma among patients younger than 20 years diagnosed from late 1994 through early 2017.
They identified a total of 38 fatal cases over more than 2 decades. The cases were distinguished primarily by their heterogeneous clinical presentation and by the diversity of the patients, their precursor lesions, and the tumor histopathology, she said in an interview.
“We were surprised to find that patients with each of these presentations could end up with a fatal course, it wasn’t just all the adolescents, or all the patients with giant congenital nevi; it really presented quite diversely.”
Rare malignancy
Melanoma is far less common in the pediatric population than in adults, with an annual incidence of 18 per 1 million among adolescents aged 15-18 years, and 1 per 1 million in children under 10 years, the authors noted.
“Melanoma in children and adolescents often has distinct clinical presentations such as association with a congenital melanocytic nevus (CMN), spitzoid melanoma, or amelanotic melanoma, which are more rarely observed in adult melanoma patients. Unique pediatric-specific clinical detection criteria have been proposed to highlight these differences, such as a tendency to present amelanotically,” they wrote.
Factors associated with worse prognosis, such as higher Breslow thickness and mitotic index, are more frequently present at the time of diagnosis in children compared with adults, particularly those diagnosed before age 11 years.
“It is unclear if this difference is secondary to diagnostic delays due to low clinical suspicion, atypical clinical presentations, or more rapid tumor growth rate, as many childhood melanomas are of nodular or spitzoid subtypes,” Dr. Hawryluk and her coauthors wrote.
Study details
The investigators sought to characterize the clinical and histopathologic features of fatal pediatric melanomas.
They found that 21 of the 38 patients (57%) were of White heritage, 7 (19%) were of Hispanic or Latino background, 1 (3%) was of Asian lineage, and 1 each were of Black African American or Black Hispanic background. The remaining children were classified as “other” or did not have their ethnic backgrounds recorded.
The “striking prevalence” of Hispanic patients observed in the study is consistent with surveillance reports of an increasing incidence of melanoma among children of Hispanic background, they noted.
The mean age at diagnosis was 12.7 years, and the mean age at death was 15.6 years.
Of the 16 cases with known identifiable disease subtypes, 8 (50%) were nodular, 5 (31%) were superficial spreading, and 3 (19%) were spitzoid melanomas. Of the 38 fatal melanomas, 10 were thought to have originated from congenital melanocytic nevi.
Outlook improving
Recent therapeutic breakthroughs such as targeted agents and immunotherapy with checkpoint inhibitors augur well for children diagnosed with melanoma, Dr. Hawryluk said.
“Fortunately, it’s not superaggressive in children at high frequency, so we generally use adult algorithms to inform treatment decisions,” she said. “It’s just important to note that melanomas that arise in congenital nevi tend to have different driver mutations than those that arise in older patients who may have lots of sun exposure.”
“Nowadays, we’re lucky to have a lot of extra tests and workups so that, if a patient does have metastatic or advance disease, they can have a better genetic profile that would guide our choice of medications,” she added.
The study was supported by a Pediatric Dermatology Research Alliance Study Support grant and Society for Pediatric Dermatology, Pediatric Dermatology Research Alliance Pilot award. Dr. Hawryluk is supported by the Dermatology Foundation and the Harvard Medical School Eleanor and Miles Shore Fellowship award. The authors reported no conflicts of interest.
SOURCE: Hawryluk EB et al. J Am Acad Dermatol. 2020 Jul 1. doi: 10.1016/j.jaad.2020.06.1010.