Aggressive infantile melanoma arising in a congenital nevus with rare and mutations: a case report and literature review of pediatric melanoma.

We report a case of aggressive melanoma in a 14-month-old girl, arising in a congenital nevus with multiple satellite lesions on the lower back and buttocks. The tumor exhibited a sarcomatous-like histology and harbored rare BRAF (p.Asp594Gly) and BCOR (p.Leu1480GlyfsTer11) mutations. Treatment included surgery and systemic therapies (nivolumab and ipilimumab, followed later by tovorafenib). Despite the initial response, the disease progressed rapidly with pulmonary metastases and lymphadenopathy. The patient's clinical course was marked by aggressive local progression and therapeutic challenges. This case highlights the rarity of such presentations and the need for further research into the clinicopathological and molecular features of infantile melanoma arising in congenital melanocytic nevus (CMN).