INTRODUCTION: The association of a medulloblastoma and a syringomyelia has been already described in rare instances albeit without symptoms related to the syrinx. CASE REPORT: The case of a 23-year-old man operated in infancy for a medulloblastoma and then treated solely with adjuvant chemotherapy is reported. He was also operated in infancy for a scaphocephaly. With a very long time delay, he has developed a Chiari I and a symptomatic cervico-dorsal syringomyelia. The symptoms attributed to the syrinx consisted of a unilateral prurigo over the left arm which was so severe to lead to self-mutilation. DISCUSSION: Clinical and magnetic resonance imaging follow-up after cervico-dorsal decompression shows a significant improvement of the symptoms together with a reduction of the size of the syrinx. This case is discussed in the light of the presumed pathophysiology of the syrinx and its exceptional clinical presentation.