A huge Morgagni hernia with compression of the right ventricle.

A 21 year old male with no relevant medical history presented to our Institution for further assessments of a right paracardiac mass founded on a chest X-ray. Chest computed tomography revealed a wide median defect of the diaphragm at the level of xiphoid process of the sternum, with the herniation of omental fat tissue in the mediastinum. Cardiac magnetic resonance confirmed the presence of a huge hernia originating from the foramen of Morgagni (sterno-costal hiatus), displacing the heart leftwards and posteriorly and compressing the right ventricle (RV), giving to it a tubular shape.The signal characteristics were typical of fat tissue, with hyperintense signal in T1 and T2 weighted black blood images and homogeneus signal suppression on STIR T2 black blood images. Short axis real time cine images, performed during deep inspiration, showed an early diastolic ventricular septal bounce, with flattening of the interventricular septum during mid-late diastole: they represented signs of diastolic dysfunction of the right ventricle, resembling a sort of "pseudo-constrictive" pathophysiological model. The patient was thus referred to surgical repair of the diaphragmatic defect.