We present an extremely rare case of mitral Ebstein's anomaly that resulted in severe mitral regurgitation (MR). A 41-year-old woman with a history of tuberous sclerosis underwent surgery. Preoperatively, it was assumed that MR had occurred due to leaflet tethering related to left ventricular posterior wall motion asynergy due to a scarred rhabdomyoma. However, surgical inspection revealed a dysplastic posterior leaflet adhering to the ventricular wall, which was completely covered by the endocardium. Both congenital mitral Ebstein's anomaly and acquired wall motion abnormality due to a scarred rhabdomyoma may have contributed to the development of severe MR in this case.
Keywords: Ebstein's anomaly; delamination failure; mitral regurgitation; mitral valve; plastering; tuberous sclerosis.