Anomalous origin of coronary arteries represents a clinical challenge not only because of the anatomical variability, but also the possible functional consequences, pathophysiological mechanisms involved and the absence of large series in the literature that would provide evidence for clinical and therapeutic orientation. The authors describe the case of a 55-year-old male patient with a long history of atypical chest pain who was considered to have a low to intermediate likelihood of coronary artery disease. Therefore, and also bearing in mind his physical limitations (congenital left leg atrophy), he was referred for cardiac CT to rule out coronary artery disease. The exam showed a left coronary artery arising from the right coronary cusp and with an interarterial course, between the aorta and pulmonary trunk. Although this is a potentially malignant anatomical variant with surgical indication, a conservative approach was chosen, considering the late diagnosis and particular risk-benefit profile. (C) 2011 Sociedade Portuguesa de Cardiologia Published by Elsevier Espana, S.L. All rights reserved.