The authors report a case of very large myxoma of the left atrium, original in terms of its mode of discovery, its very calcified appearance, in a totally asymptomatic elderly patient. A complete ultrasound assessment, catheterization, and coronary angiography allowed assessment of the morphology, topography, blood supply and cardiac repercussions of this tumour. Myxoma of the left auricle is the commonest cardiac tumour, with multiple clinical features and presentations. This benign tumour arises from embryonic vestigial remains, usually in the fossa ovale. The present case is original by its unusual mode of discovery in a totally asymptomatic patient.