This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
True pseudo rosettes are seen in all except 
Select and explain. 
A. Neuroblastoma, B. Retinoblastoma, C. Medulloblastoma, D. Thecoma
D: Thecoma
Answer: D: Thecoma 
Explanation: 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.