Intracardiac thrombus

Case contributed by Dr Bruno Di Muzio

Patient Data

Age: 40 years
Gender: Male

CT Chest

There is a hypodense mass in the right atrium.

The lungs and pleural spaces are clear and the remainder of the study is unremarkable. 


Cardiac MRI

Pedunculated right atrium mass with homogenous low signal. 


  • Three pieces of pink/yellow tissue with focal muscle, 17mm- 25x15x8mm. 1RS of each on for frozen section. Frozen Section Diagnosis:  Cardiac muscle with overlying tissue with haemosiderin pigment. Differential thrombus vs myxoma. Await paraffin.
  • Labelled "Right atrial mass".  Multiple tan friable fragments of tissue, <1-50x35x20mm. The margins are ragged. The cut section reveals a firm variegated tan/yellow lesion with patchy haemorrhage but no necrosis. There is no normal myocardium or endocardium identified.


  • A. Sections show surface amorphous eosinophilic material deep to which there is collagenous matrix focally myxoid within which some spindled cells are seen admixed with scattered haemosiderin macrophage and present overlying myocardium with focal areas showing ingrowing blood vessels.
  • B. Sections consist predominantly of an amorphous eosinophilic material showing focal calcification


  • A. Specimen base - organising thrombus.
  • B. Right atrial mass - features in keeping with a calcified long-standing blood clot.

Case Discussion

Incidentally found right atrium intracardiac mass. Unfortunately, no postcontrast MRI images were obtained in this case, which would help in distinguishing the most common causes for such mass: myxoma vs. thrombus.

Further histology confirmed a long-standing intracardiac thrombus.   

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Case information

rID: 66231
Published: 17th Feb 2019
Last edited: 17th Feb 2019
System: Vascular
Inclusion in quiz mode: Included

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