The following are multiple choice questions (with answers) about medical knowledge.   **Question:** A 45-year-old woman comes to the emergency department because of intermittent chest pain and palpitations. She also complains of dyspnea on exertion and has had a 4.5-kg (10-lb) weight loss in the past 2 months despite normal appetite. She has no history of serious medical illness. Cardiac examination shows an irregularly irregular rhythm and a grade 3/6, low pitched, rumbling, mid-diastolic murmur heard best over the apex. Diffuse wheezing and bilateral rales are present in the lung bases. A transthoracic echocardiogram shows a left-ventricular ejection fraction of 40% and a mass in the left atrium. A biopsy of the mass is likely to show which of the following?   (A) Nonencapsulated groups of well-differentiated skeletal muscle cells   (B) Mixture of cells from different germinal layers   (C) Encapsulated cluster of mature fat cells   (D) Nests of atypical melanocytes
['(D) Nests of atypical melanocytes <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Nonencapsulated groups of well-differentiated skeletal muscle cells \n (B) Mixture of cells from different germinal layers \n (C) Encapsulated cluster of mature fat cells \n (D) Nests of atypical melanocytes <> possible answers', '  A 45-year-old woman comes to the emergency department because of intermittent chest pain and palpitations. She also complains of dyspnea on exertion and has had a 4.5-kg (10-lb) weight loss in the past 2 months despite normal appetite. She has no history of serious medical illness. Cardiac examination shows an irregularly irregular rhythm and a grade 3/6, low pitched, rumbling, mid-diastolic murmur heard best over the apex. Diffuse wheezing and bilateral rales are present in the lung bases. A transthoracic echocardiogram shows a left-ventricular ejection fraction of 40% and a mass in the left atrium. A biopsy of the mass is likely to show which of the following? <> context@']