A 35-year-old woman is brought to the emergency department due to severe right leg pain. She is a concert pianist with no known medical issues. During rehearsal, she began experiencing cramping of the right foot that did not improve with stretching or rest. The pain quickly spread to her calf, and the patient now rates the pain as 9 out of 10 in intensity. On examination, the right foot and calf appear pale and cool compared with the left, and sensation is diminished. Right-sided dorsalis pedis and posterior tibial pulses are absent, and the popliteal pulse is barely palpable. Emergency embolectomy is performed and a gelatinous mass causing arterial occlusion is successfully removed. Histopathologic section of the mass is shown in the exhibit.
Which of the following is the most likely origin of this patient's embolus?

Question

A 35-year-old woman is brought to the emergency department due to severe right leg pain.  She is a concert pianist with no known medical issues.  During rehearsal, she began experiencing cramping of the right foot that did not improve with stretching or rest.  The pain quickly spread to her calf, and the patient now rates the pain as 9 out of 10 in intensity.  On examination, the right foot and calf appear pale and cool compared with the left, and sensation is diminished.  Right-sided dorsalis pedis and posterior tibial pulses are absent, and the popliteal pulse is barely palpable.  Emergency embolectomy is performed and a gelatinous mass causing arterial occlusion is successfully removed.  Histopathologic section of the mass is shown in the exhibit. 
 Which of the following is the most likely origin of this patient's embolus?

Quizplus · Accepted Answer

11ec160b_38c2_1eae_9249_bd28f47d04f7_MD0001_00 This patient presented with acute limb ischemia, as evidenced by the 6 Ps: pain, pallor, poikilothermia (coolness to touch), paresthesia, paralysis, and reduced or absent pulses. The ischemia resulted from systemic embolization of a gelatinous mass, with histopathology demonstrating an amorphous extracellular matrix with scattered stellate myxoma cells in mucopolysaccharide ground substance; this is consistent with tumor fragments from an atrial myxoma. Myxomas are the most common primary cardiac neoplasm. Approximately 80% of these benign tumors originate in the left atrium. Patients can initially present with nonspecific constitutional symptoms (eg, fatigue, low-grade fever, weight loss) or systemic embolization (eg, stroke, mesenteric ischemia, acute limb ischemia), as in this patient. In addition, the tumor can cause position-dependent obstruction of the mitral valve, leading to signs and symptoms that mimic mitral valve stenosis (eg, dyspnea, cough, mid-diastolic murmur). (Choices A and E) The aortic and mitral valves can be the source of systemic embolism due to vegetations from bacterial endocarditis or nonbacterial thrombotic endocarditis (Libman-Sacks endocarditis). However, only 5% of myxomas originate on the mitral valve and even fewer originate on the aortic valve. (Choice B) A complex atherosclerotic plaque or mural thrombus attached to the walls of the descending aorta can lead to systemic embolization to the kidneys, bowel, or lower extremities. However, myxomas very rarely originate from the aorta. (Choice D) A mural thrombus can originate in the left ventricular cavity in patients with severe left ventricular systolic dysfunction, especially with recent anterior wall myocardial infarction. Other than the left atrium, the right atrium is the most common site for myxoma development. It is quite rare for myxomas to originate in either ventricle. Educational objective: Myxomas are the most common primary cardiac neoplasm and approximately 80% originate in the left atrium. Patients may present with symptomatic mitral valve obstruction that may worsen with certain body positions, constitutional findings (eg, fever, weight loss), or systemic embolization (eg, stroke, mesenteric ischemia, acute limb ischemia). __________ References: Cardiac myxomas: 24 years of experience in 49 patients. (http://www.ncbi.nlm.nih.gov/pubmed/12467822) Cardiac myxoma: diagnostic approach, surgical treatment and follow-up. A twenty years experience. (http://www.ncbi.nlm.nih.gov/pubmed/10064362)

A 35-Year-Old Woman Is Brought to the Emergency Department Due