Background Quadricuspid aortic valve is rare and occasionally associated with aortic regurgitation and ascending aortic dilatation. Recent studies suggest an association of aortic regurgitation with ascending aortic medial degeneration. Case Description Histologic evaluation of ascending aortic tissue of two individuals with regurgitant quadricuspid aortic valve, one dilated, one non-dilated, yielded comparable degeneration in the Media. Conclusion Regurgitation of quadricuspid aortic valve may lead to the degeneration of Tunica media of the ascending aorta.