This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
A six yr. old female presents with constipation and urinary retention. On examination a presecral mass is noted. Most probable dignosis is 
Select and explain. 
A. Pelvic neuroblastoma, B. Rectal duplication cyst, C. Sacrococcygeal teratoma, D. Anterior Sacral meningocele
D: Anterior Sacral meningocele
Answer: D: Anterior Sacral meningocele 
Explanation: .meningocele It is the herniation of meninges through a weak point of spine where bony fusion has not taken place effectively. Swelling is covered with pia mater and arachnoid mater without dural covering and contains CSF. Clinical Features - * Present since bih. * Soft, cystic, fluctuant with transillumination. * Signs of compressibility. * Expansile impulse when asked to cough or when child cries. Location * Lumbosacral - commonest. * Occipito cervical - 2nd most common. ref:SRB&;s manual of surgery,ed 3,pg no 1053