Sudden infantile death due to left ventricular myocardial ischemia associated with undiagnosed single coronary artery of Lipton's type LII-B.

Single coronary artery (SCA) is a rare malformation, particularly in isolation without other congenital heart defects. Here, we describe a case of sudden infantile death due to myocardial ischemia associated with undiagnosed SCA. A 1-year-and-7-month-old female infant died suddenly after vomiting at home. A medicolegal autopsy revealed that the orifice of the right coronary artery (RCA) was absent. As expected, the left coronary artery was detached from the left coronary sinus; however, the ostium was covered with a flap-like fibrous ridge. The thin RCA originated from the left main trunk (LMT) and passed between the aorta and pulmonary artery trunk. The left circumflex artery branched from the LMT at a right angle. Judging from the origin and course of the anomalous RCA, the deceased was diagnosed with SCA of Lipton's type LII-B. Microscopic examination revealed ischemic changes around the endocardium of the lateral wall of the left ventricle (LV) rather than on the side of the abnormal RCA. This evoked attention, as there appeared to be some discrepancy. To the best of our knowledge, this is the first case report describing sudden infantile death related to LV myocardial ischemia associated with undiagnosed SCA of Lipton's type LⅡ-B.