This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: miscellaneous, Subject name: Pathology
[{'content': 'Which of the tumors are unique to pregnancy \nSelect and explain. \nA. Luteoma, B. Serous cystadenoma, C. Mucinous cystadenoma, D. Teratoma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Pregnancy luteomas are rare, nonneoplastic lesions of the ovary thought to be caused by the hormonal effects of pregnancy. Most of these patients are asymptomatic with the ovarian enlargement being incidentally discovered during imaging or surgery. Some patients develop hirsutism or virilization during late pregnancy. Luteomas spontaneously regress postpaum. It may be a diagnostic and management challenge as it can mimic the presentation of malignant ovarian tumors.', 'role': 'assistant'}]