Medulloblastoma metastases almost always localize to the leptomeningeal surface of the brain and spinal cord, which has led to the assumption that the only mechanism of metastatic seeding is via dissemination of primary tumour cells into the cerebrospinal fluid and subsequent distal re-colonization of the leptomeninges. However, Garcia et al. detected circulating tumour cells (CTCs) in the blood of therapy-naive patients with medulloblastoma. Use of flank xenografts and a parabiosis model in mice confirmed that medulloblastoma cells could disseminate via the blood to reach the leptomeningeal space and establish leptomeningeal metastases. Furthermore, the CC-chemokine ligand 2 (CCL2)–CC-chemokine receptor 2 (CCR2) axis was identified as driving haematogenous dissemination of medulloblastoma in vivo. Recognition of this metastatic route has implications for the diagnosis and treatment of this metastatic paediatric disease.