The exact pathogenesis of<unk>  is not entirely clear, although several factors are thought to contribute to its development. One factor that may contribute to the development of<unk>  is the abnormal postzygotic development of melanoblasts. This mutation would possibly occur within the neural crest of the ectoderm. After the mutation occurs, these cells would then migrate to the meninges as the precursors to the malignant or benign melanocytes. This mutation may be due to abnormal expression of hepatocyte growth factor/scatter factor by the mesenchymal cells within the neural crest. Another proposed cause of<unk>  is a mutation of the NRAS gene at codon 61. This mutation has been detected in patients with congenital melanocytic nevi, as well as those with melanocytic tumors of the central nervous system. The mutation would also likely occur within the neural crest.
Neurocutaneous melanosis
Nevus anemicus
Phakomatosis pigmentokeratotica
Granulomatous slack skin
Blue nevus
Erythema dyschromicum perstans
Sparganosis
Hypertrichosis cubiti