This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
[{'content': "Microscopic examination of a tumor shows 'Schiller Duval Bodies' which are characteristically seen in: \nSelect and explain. \nA. Endodermal sinus tumor, B. Choriocarcinoma, C. Granuloma cell tumor, D. Arrhenoblastoma", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Yolk sac tumor (endodermal sinus tumor) is a germ cell tumor. The clinical presentation is similar to that of sarcoma botryoides, and the most common symptom is bloody vaginal discharge. Grossly, yolk sac tumor appears polypoid or sessile and often ulcerated. On microscopic examination, these tumors most commonly have a reticular pattern. A classic finding, although not always present, is the Schiller-Duval body. This is a papilla with a single central vessel. Ref: Hoffman B.L., Schorge J.O., Schaffer J.I., Halvorson L.M., Bradshaw K.D., Cunningham F.G., Calver L.E. (2012). Chapter 32. Vaginal Cancer. In B.L. Hoffman, J.O. Schorge, J.I. Schaffer, L.M. Halvorson, K.D. Bradshaw, F.G. Cunningham, L.E. Calver (Eds), Williams Gynecology, 2e.', 'role': 'assistant'}]