This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Tumors, Subject name: Ophthalmology
Second common malignancy in patients of retinoblastoma is? 
Select and explain. 
A. Osteosarcoma, B. Ewing s sarcoma, C. Medulloblastoma, D. Osteoblastoma
A: Osteosarcoma
Answer: A: Osteosarcoma 
Explanation: ANSWER: (A) OsteosarcomaREF: Khurana 4th ed p. 281Heritable germ line cases of retinoblastoma develop bilateral tumours and multifocal tumours, and carry a predisposition to develop trilateral tumours most notably pinealoblastomas and osteosarcomas.Retinoblastoma is most common primary intraocular malignanacy of childhood.It is characterized by Flexner winterstiener rosette , homer - wright rosetteLeucocoria or cat's reflex is most common manifestation.Strabismus is second most common manifestation.Predisposing gene is 13ql4