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: Radiology
[{'content': "Solitary hypoechoic lesion of the liver without septate or debris is most likely to be- \nSelect and explain. \nA. Hydatid cyst, B. Caroli's disease, C. Liver abscess, D. Simple cyst", 'role': 'user'}, {'content': 'Answer: D \nExplanation: A solitary hypoechoic lesion without any septae or debris is most likely to be a simple cyst.\xa0\n\n\xa0 \xa0 \xa0 \xa0 \xa0 Option b requires specific mention here:-\n\nSolitary hypoechoic / anechoic lesion without septae or debris can occur in the early stage of evolution of hydatid cyst (Type 1 / Simple cyst). However, the diagnosis of hydatid cyst may be considered when focal thickening of the wall is present or when fine hyperechoic spots, due to the hydatid sand, appear in the dependent areas.\n\n\xa0 \xa0 \xa0 \xa0 \xa0 Solitary hypoechoic aseptate lesion\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0→\xa0Simple liver cyst\n\xa0 \xa0 \xa0 \xa0 \xa0 Solitary hypoechoic aseptate lesion with\xa0\xa0\xa0\xa0→\xa0Type 1 (simple) hydatid cyst\xa0\n\xa0 \xa0 \xa0 \xa0 \xa0 hyperechoic spots due to hydatid sand', 'role': 'assistant'}]