Rosettes

ROSETTES
• Rosettes are pathological findings characterised by halo or spoke wheel arrangement of cells surrounding a central core or hub.
• Four Types of rosettes are seen -

1)Flexner wintersteiner rosettes –• It’s an pseudorosette. • Halo of cells surrounding empty central hub • Seen in---- retinoblastoma( more characteristic). • Also seen in--- PNET; Medulloblastoma; Pinealoblastoma

2) Homer wright rosette-• A halo of cells surrounds a space which contains a meshwork of fibres ( neuropil rich center ) • Characteristically seen in ----neuroblastoma and medulloblastomas. • May be seen in –PNET; Pinealoblastoma

3) Peri vascular pseudo-rosettes -• A halo of cells surrounds a blood vessel. • Seen in --- ependymomas; medulloblastomas; PNET; Central neurocytomas ; Glioblastomas

4) True Ependymal Rosette :-• Consists of tumor cells surrounding an empty lumen. • Only present in a small percentage of well-differentiated ependymoma). • Rosettes are pathological findings characterised by halo or spoke wheel arrangement of cells surrounding a central core or hub.