 A perivascular pseudorosette consists of a spoke-wheel arrangement of cells with tapered cellular processes radiates around a wall of a centrally placed vessel.The modifier “pseudo” differentiates this pattern from the Homer Wright and Flexner-Wintersteiner rosettes,
perhaps because the central structure is not actually formed by the tumor itself, but instead represents a native, non-neoplastic element.Also, some early investigators argued about the definition of a central lumen, choosing “pseudo” to indicate that the hub was
not a true lumen but contained structures.