Vascular bundles and wickerworks in childhood brain tumors.

We reviewed 114 childhood brain tumors and brain sections from 30 children with no nervous system lesions to determine the incidence of vascular bundles (VB) and vascular wickerworks (VW). VB consist of a group of small blood vessels running parallel to each other. VW denote spiralling or twisting of two or more small blood vessels around one another, resembling vines. By light microscopy, VB cannot be differentiated from VW; both appear as a group of small blood vessels oriented in the same direction. VB and VW have been described in normal and abnormal brains at all ages, in association with aging, in neovascularization following necrosis, and in brain tumors. They occur rarely in normal brains, but are a common histological feature of cerebellar pilocytic astrocytomas in contrast to diencephalic pilocytic astrocytomas, anaplastic astrocytomas of cerebrum and cerebellum, and meningiomas.