This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pediatric Surgery, Subject name: Surgery
Sacroccygeal teratoma is embryological remnant of:- 
Select and explain. 
A. Neural tube, B. Allantois, C. Notochord, D. Primitive streak
D: Primitive streak
Answer: D: Primitive streak 
Explanation: Sacrococcygeal teratoma Teratomas occur most frequently in the neonatal period, sacrococcygeal region is the MC site More common in females Thought to be a derivative of the primitive streak Most often an obvious external presacral mass. Most of the tumor is usually external, with a minimal intrapelvic presacral component These lesions should be carefully followed with serial USG until delivery because the blood supply to the tumor may grow to the point of stealing a significant propoion of placental blood flow to the fetus The development of hydrops or placentomegaly is associated with a poor prognosis Most neonatal SCTs are benign Incidence of malignancy is related to age at time of diagnosis and is most frequently represented as yolk sac tumors or embryonal carcinomas. Treatment Complete surgical excision through a chevron-shaped buttock incision. Resection of the cocyx is critical because failure to remove this structure results in significantly higher local recurrence rates.