Left atrial wall haematoma is a very uncommon entity, associated mainly to cardiac surgery, interventional procedures, or trauma. Spontaneous cases are supposed to be associated with left atrial wall pathology. We present a case of a 53-year-old male who was admitted for prolonged chest pain, with transthoracic and transesophagic echocardiography documentation of a left atrial mass in close proximity to a mitral annular calcification. Tissue characterization with cardiac magnetic resonance suggested the aetiology of the mass, which was confirmed histologically.