Co-existent pilocytic astrocytoma with acute B-cell leukemia within the cerebellum.

Pilocytic astrocytomas are the commonest childhood brain tumor. They are typically benign and usually are solitary neoplasms. To our knowledge, only one report of a pilocytic astrocytoma with leukemia has been previously issued. We herein describe the first case with documented histopathology of a 2-year-old boy who had a cerebellar pilocytic astrocytoma co-localized with an acute B-lymphoblastic leukemia. We speculate that chemotactic migration of leukemic cells to the pilocytic astrocytoma may be partly mediated through vascular endothelial growth factor (VEGF) and VEGF receptors.