This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Orbit and Adnexa, Subject name: Ophthalmology
What is the commonest tumour to metastasize to the orbit in children? 
Select and explain. 
A. Hodgkin's lymphoma, B. Myeloid leukemia, C. Neuroblastoma, D. Medulloblastoma
C: Neuroblastoma
Answer: C: Neuroblastoma 
Explanation: METASTATIC ORBITAL TUMOURS : These involve the orbit by haematogenous spread from a distant primary focus and include the following: * Neuroblastoma -- from adrenals and sympathetic chain. Nephroblastoma --from kidneys. Carcinoma -- from lungs, breast, prostate, thyroid and rectum. Malignant melanoma -- from skin. Ewing's sarcoma --from the bones. Leukaemic infiltration. Commonest tumor to metastasize in children is Neuroblastoma-Raccoon eye sign due to periorbital ecchymosis.