This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Osteology, Subject name: Pathology
Ewing's sarcoma arises from 
Select and explain. 
A. Endothelial cells, B. Osteocytes, C. Mesoderm, D. Primitive neuroectodermal cells
D: Primitive neuroectodermal cells
Answer: D: Primitive neuroectodermal cells 
Explanation: Ans. d (Primitive neuroectodermal cells). (Ref. Robbin, Pathologic Basis of Diseases 5th/833)PNETs# Ewing's Sarcoma is the highly malignant primary bone neoplasm having specific cytogenetic analysis i.e. t (11,12), characterized by small round cells (pseudo-rossets) and is thought to be a primitive neuroectodermal tumor (PNET) with 75% patients being < 20 years age and having male predilection.# Other PNETs include- Medulloblastoma,- Pineoblastoma,- Neuroblastoma,- Askin tumor,- Retinoblastoma, etc.