The association of a syndrome of a degenerative nature such as syringomyelia and a neuroblastoma can be of clinical interest. We will describe the case of a young female suffering from a retroperitoneal neuroblastoma and secondary development of syringomyelia. The possible pathogenetic link between these two pathologies will be discussed. Firstly, the dysontogenetic interpretation will be underlined. Other hypotheses will concentrate on the presence of tumors within the cord, which tend to cavitate, and furthermore, on the association between the edema and some diseases such as neoplasma, traumas, and on arachnoiditis as a major pathogenetic factor in syringomyelia. The existence of a possible link between arachnoiditis and the radiotherapy received by the patient after the surgical excision of the retroperitoneal neuroblastoma, will be discussed. Lastly a further pathogenetic hypothesis will be pointed out: an intramedullary softening due to disturbed blood supply, caused by the extramedullary neoplasm.