[Tumours of the heart: diagnostic dilemma].

Introduction: Mitral annular calcification is a degenerative process of the fibrosus support structure of the mitral apparatus, usually spreading over the posterior mitral leaflet.

Case Outline: A 66-year-old woman with shortness of breath and palpitations was referred to our institution. Echocardiography showed a round, echo-dense mass, resembling a tumour, in the posterior mitral annulus, with the third degree mitral regurgitation.