Acute ruptured mycotic aneurysm mimicking myocardial tumor with ST elevation myocardial infarction

Excerpt

A 50-year-old woman presented with chest tightness and shock. She had a history of hypertension and diabetes, and she had just been discharged for Staphylococcus aureus infection. Electrocardiography showed complete atrioventricular block and ST elevation over inferior leads giving the impression of myocardial infarction. Coronary angiography was therefore performed and demonstrated one huge coronary aneurysm at the proximal left anterior descending artery (LAD) (Fig. 1a). Also, the totally occluded right coronary artery (RCA) indicated the infarct-related artery (Supplementary Fig. 1a). Owing to failed attempts to open the RCA, computed tomography was utilized to delineate the structures before bypass surgery. Surprisingly, in addition to the LAD pseudoaneurysm (Fig. 1b) a focal mass-like lesion encased the proximal RCA (Supplementary Fig. 1b). Fever and profound shock raged but emergent surgery could not prevent the patient’s death. Postmortem blood culture yielded S. aureus. Autopsy revealed the ruptured pseudoaneurysm in the LAD and subsequent hematoma, which caused myocardial necrosis of the anterior wall (Fig. 1c). Similarly, hematoma along the right atrium, supposedly from the ruptured pseudoaneurysm, also compromised the RCA (Supplementary Fig. 1c). The disruptive single layer pseudoaneurysm and dissection flap were observed microscopically. Atherosclerosis and thrombosis inside the LAD and RCA contributed to the occlusion (Fig. 1d, Supplementary Fig. 1d). Coronary artery mycotic aneurysm is a rare cause of myocardial infarction. The consequent hematoma caused by a ruptured aneurysm may imitate a cardiac tumor. As in the current case, imaging investigations are useful; however, only prompt surgery and histologic proof indicate a definite diagnosis and better outcome.

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