Neurocutaneous melanosis presenting as an intradural mass of the cervical canal: magnetic resonance features and the presence of melanin as a clue to diagnosis: case report.

We present a case of neurocutaneous melanosis in a 1-year-old child who presented with progressive quadriparesis created by an infiltrating extra-axial neoplastic melanin-producing tumor at the foramen magnum. This extensive intra-arachnoid mass filled the basal cisterns of the brain and surrounded the upper cervical cord. An imaging clue to the diagnosis was apparent as T1-weighted shortening on magnetic resonance in the pia and/or cortex of the cerebellar folia, suggesting the presence of melanin.