Different vascular patterns of medulloblastoma and supratentorial primitive neuroectodermal tumors.

Astrocytoma vasculature patterns differ according to histological grade of malignancy with glioblastoma multiforme (WHO grade IV) showing most extensive endothelial proliferation. Here, we determined whether the vascular patterns of medulloblastoma and supratentorial primitive neuroectodermal tumors (PNETs), which can be hardly distinguished histopathologically, differ. We evaluated the spatial organization of vessels in medulloblastomas and PNETs using antibodies to von Willebrand factor (vWF) and CD34. Medulloblastoma capillaries showed slight endothelial cell hyperplasia. Microvessels sprouted from the capillaries and formed glomeruloid clusters. There were areas with chains of unopposed endothelial cells (3-10 cells). Supratentorial PNETs had highly branched capillaries with extensive endothelial cell hyperplasia. Glomeruloid arrays of microvessels extended from the capillaries. Small fragments of endothelial tubes were scattered throughout the tumor. Therefore, medulloblastomas and supratentorial PNETs showed different spatial organization of tumor vessels which can be used for differentiation of each tumor entity. These vascular patterns may reflect different tumor derived angiogenic stimuli.

Radiology of olfactory neuroblastoma.

Olfactory neuroblastoma is often misdiagnosed pathologically. The authors reviewed eight such cases in which the pathological findings met strict criteria. These neoplasms are locally invasive in the nose and paranasal sinuses, with frequent intraorbital and intracranial extension as well as distant metastases. A rare primary presentation in the sphenoid sinus-clivus region is described. Computed tomography is the procedure of choice in defining intraorbital extension and is complementary to precision laminagraphy for defining intracranial extension. Angiography frequently shows hypervascularity and may be of further help in assessing intracranial extension.