A New Case Linking a Somatic NRAS Variant to Encephalocraniocutaneous Lipomatosis.

Encephalocraniocutaneous lipomatosis (ECCL) is a rare somatic disorder caused by mutations in various genes of the RAS-MAPK pathway. Distinctive features of ECCL include nevus psiloliparus, scalp alopecia, ocular choristomas, and intracranial lipomas. ECCL is most commonly associated with FGFR1 and KRAS mutations. An NRAS variant causing ECCL has only been reported in the literature once. We present the case of a female infant with ECCL, harboring an NRAS somatic mutation, variant c.37G>C (p.Gly13Arg). This is the second reported case of an NRAS variant in ECCL and the first to document an associated intracranial lipoma. The report highlights the genotypic, clinical, and neuroradiological presentation of ECCL, its overlap and distinctions with other mosaic RASopathies, and reviews the recommended diagnostic approach when ECCL is suspected.