Posterior quadrantic dysplasia with localized hemimegalencephaly in a patient with giant congenital melanocytic nevus: First case report.

Giant congenital melanocytic nevus (GCMN) is associated with neurocutaneous melanocytosis and various other neurological complications. Its association with migrational anomalies of the brain is extremely rare. Herein, we document the first case of GCMN in a one-day-old baby associated with localized hemimegalencephaly (HME) of the brain with extensive malformation of cortical development including polymicrogyria, pachygyria and sublobar dysplasia, limited to an enlarged quadrant of the brain. HME and GCMN are considered embryological anomalies of cell migration and proliferation. We discuss the unusual magnetic resonance imaging findings along with a brief review of the literature. To the best of our knowledge, our case is the first to report the association of GCMN with localized HME.