The heart is an infrequent location for primary tumors. When they appear, they usually emerge as myxomas (slow growth bening forms). We present a 68-year-old man who was discovered of a left atrial mass in a routinary echocardiography. A transesophageal test was then performed to better study the finding. We highlight “Transillumination”as a new technology which processes the 3D image by operating with the image’s enlightenment. It provides a better tissue characterization, allowing a superior description of the mass, in this case. The bulk was surgically removed, and its histological analysis established the diagnosis of a myxoma.