Mural Thrombus In Left Atrium

Clinical History

Incidental finding at necropsy on 80 year old who died of pneumonia following motor car accident in which he sustained fractures.


The specimen is of opened left atrium with mitral valve below. The specimen is displayed to show the endocardial surface. In the atrium attached to the region of the fossa ovalis, is a spherical mass 2.5 cm in diameter. The mass has a haemorrhagic mucoid surface and this is reflected in the internal structure seen on the cut surface. The cut surface shows a rusty staining probably due to old haemorrhage. The mitral valve shows some nodular thickening at the margin of closure. Micro: There was oedematous and somewhat mucoid fibrous tissue, there being numerous macrophages filled with brown pigment. The pathologist considered that the mass resembled an old thrombus rather than a true neoplastic "myxoma".