Atrial mass: a myxoma?

A middle-aged woman with a history of resected colorectal cancer and receiving chemotherapy presented with a right atrial mass and the provisional diagnosis of myxoma supported by echocardiography, computed tomography, and magnetic resonance imaging. Successful surgical removal revealed organized thrombus instead. Atrial thrombus may be mistaken for myxoma and long-term intracardiac indwelling catheters can be thrombogenic.

Case History

A 50‐year‐old Caucasian woman with a history of a resected colorectal cancer was receiving chemotherapy for about 6 months. During routine follow‐up, a right atrial mass was picked up by echocardiography (Fig. 1A). Complete investigational work‐up with computed tomography (Fig. 1B) and magnetic resonance imaging (Fig. 1C) revealed a tumor adherent to the right atrial free wall with a distinct stalk. The provisional diagnosis of myxoma was made and surgery was advised.

Figure 1

Right atrial (RA) pediculate mass signified by arrows as depicted by means of ECHO (A), CT‐scan (B), and MRI (C).

The patient underwent cardiac surgery with cardiopulmonary bypass support and cardioplegic arrest. Following right atriotomy, a pediculate mass was found strongly adherent to the right atrial free wall opposite the indwelling Hickman catheter. This was successfully excised en block with part of the atrial wall (Fig. 2). Histology, however, showed organized thrombus.

Figure 2

Resected mass.

Despite modern available imaging modalities, it may be difficult to differentiate between atrial masses 1. Organized thrombus with a distinct stalk mimicking myxoma has been reported before in patients with some form of cardiac disease especially atrial fibrillation 2. Right atrial thrombus formation in the absence of cardiac disease, nevertheless, raises questions regarding anticoagulation protocols that may have to take into consideration the presence of intra‐atrial indwelling catheters.

Conflict of Interest

None declared.