This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Systemic Pathology, Subject name: Pathology
Which of the following are histological features of medulloblastoma as shown in the diagram? 
Select and explain. 
A. Small round blue cells, B. Scant amount of cytoplasm and hyperchromatic nuclei, C. Homer-Wright rosettes, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: Medulloblastoma is very densely cellular, with sheets of anaplastic cells. Individual tumor cells are small, with scant cytoplasm and hyperchromatic nuclei that are frequently elongated or crescent shaped. Mitoses are abundant, and markers of cellular proliferation, such as Ki-67, are detected in a high percentage of the cells. The tumor may express neuronal (neurosecretory) granules, form Homer-Wright rosettes and express glial markers (e.g., GFAP).