During auscultation of the heart, there is a rare but distinctive sound which, at a teaching hospital, will have every intern, resident, and cardiologist running to listen. This elusive creature is the tumor plop. Caused by an atrial myxoma, the tumor plop is heard best at the sternal border of whichever side the atrial myxoma has developed on (usually on the left side).
The plop is very, well, plop-like. More than that it is difficult to describe. Anyone with a half-decent stethoscope will not miss this sound if present. The sound is positional, coming and going depending on the patient's posture. If this sound is heard, an echocardiogram is the next step, almost always followed by surgical resection of the tumor which is most certainly present.
Please see atrial myxoma for more details.
Author's note: I have had the fortune to hear this sound just once. I will never forget it...