Ascending aortic aneurysm in a fetus due to a benign nodular myofibroblastic lesion.

A fetal echocardiogram at 20 weeks of gestation revealed a large ascending aortic aneurysm in the presence of a normal aortic root and normal intracardiac anatomy. No other abnormalities were noted in the fetus. Upon termination of pregnancy, histopathological examination revealed an isolated benign nodular myofibroblastic lesion of likely hamartomatous origin, a first description of such pathology contributing to the formation of an aneurysm in the ascending aorta.