From the Journals

Trametinib effectively treats case of giant congenital melanocytic nevus



A 7-year-old girl’s giant congenital melanocytic nevus (GCMN) was effectively treated with the MEK inhibitor trametinib, according to acase report presented in Pediatrics.

Her nevus covered most of her back and much of her torso and had thickened significantly over the years since initial presentation to the point of disfigurement, even invading the fascia and musculature of the trunk and pelvis, reported Adnan Mir, MD, PhD, of the University of Texas Southwestern Medical Center, Dallas, and his coauthors. Furthermore, she presented with intractable pruritus and pain that interfered with sleep and responded minimally to treatments. Although initial immunohistochemical staining and gene sequencing did not reveal any mutations, such as BRAF V600E, further testing uncovered an AKAP9-BRAF fusion.

There are few if any effective ways of treating GCMNs. With that knowledge, as well as general theories of the mechanism GCMNs in mind, the patient’s health care team decided to try a 0.5-mg daily dose of trametinib when she was 7 years old. Her pruritus and pain resolved completely, and after 6 months of treatment with trametinib, repeat MRI “revealed decreased thickening of the dermis and near resolutions of muscular invasion.” According to the patient’s family, her quality of life improved dramatically.

SOURCE: Mir A et al. Pediatrics. 2019;143(3):e20182469.

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