Histopathology of Giant Coronary Artery Aneurysm Associated with Coronary Artery Fistula

: Giant coronary artery aneurysms related to coronary fistula are rare, and the precise mechanisms by which they occur are unknown. We present a case of giant coronary artery aneurysm of the left coronary artery to the pulmonary artery fistula with a lack of internal and (or) external elastic lamina and medial degeneration.