We report the case of a 9-year-old boy with progressive thoracic scoliosis and crossed hemihypertrophy who was discovered with a Chiari 1 malformation and syringomyelia. These disorders are connected by complex physiopathological mechanisms; their association deserves attention. This observation reviews the importance of the clinical examination, particularly the neurological exam, in childhood scoliosis. The features suggesting a neurogenic background of spine deformation should be sought. Scoliosis with hemihypertrophy can be the sign of an underlying neurological abnormality.