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': 'A 26-year-old female presents with 8 week amenorrhoea with pain in left lower abdomen. On USG thick endometrium with mass in lateral adnexa is visible. Diagnosis is likely to be: \nSelect and explain. \nA. Ectopic pregnancy, B. Torsion of dermoid cyst, C. Tubo ovarian mass, D. Hydrosalpinx', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The diagnosis of ectopic pregnancy should be considered strongly when any of the foregoing symptoms (amenorrhea followed by vaginal bleeding and abdominal pain on the affected side) are repoed by a reproductive-aged women. Transvaginal sonography and serial serum beta-hCG measurements are the most valuable diagnostic aids to confirm clinical suspicions of an ectopic pregnancy. With TVS, a gestational sac is usually visible between 4 1/2 and 5 weeks, the yolk sac appears between 5 and 6 weeks, and a fetal pole with cardiac activity is first detected at 5 1/2 to 6 weeks. Ref: Hoffman B.L., Schorge J.O., Schaffer J.I., Halvorson L.M., Bradshaw K.D., Cunningham F.G., Calver L.E. (2012). Chapter 7. Ectopic Pregnancy. 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'}]