Hydatid cyst confined to the papillary muscle: a very rare cause of mitral regurgitation.

Cardiac involvement of hydatid cysts is rare. Hydatidosis of the valvular apparatus can be treated successfully by the careful application of valvular surgical procedures. To the best of our knowledge, cardiac hydatidosis confined to the anterolateral papillary muscle has not been reported. Herein, we present a case involving a hydatid cyst that was located in a cardiac papillary muscle and that caused mitral regurgitation in a 37-year-old woman. The cyst was removed by papillary muscle incision, and the mitral valve was repaired. The patient experienced an uneventful recovery.