True pseudo rosettes are seen in all except
Thecoma *Neuroblastoma: Homer-Wright pseudo rosettes can be found in which the tumor cells are concentrically arranged around the central space filled with neutrophil. *Medulloblastoma: The tumor has the potential to express neural cells or Homer Wright rosettes as occur in neuroblastoma. *Retinoblastoma: In well differentiated tumors there are Flexner-Winter-Steiner rosettes and fleurettes reflecting photoreceptor differentiation. *Thecoma: They are composed of well differentiated fibroblasts with more or less scant collagenous connective tissue interspace between the cells.
Neuroblastoma
Retinoblastoma
Medulloblastoma
Thecoma