Pleomorphic sarcoma metastatic to the duodenum?

We read with interest Hawasli et al. report of a pleomorphic sarcoma metastatic to the left atrium.[1] However, we suspect that the true site of origin is unknown, and may in fact be the heart. There are several reasons for this:

the histological appearance is similar to left atrial tumors that have already been reported;[2]

the left atrium, is the most common site of cardiac pleomorphic sarcoma;

all metastatic sarcomas to the heart have been in the right atrium or ventricle or have involved myocardium and/or pericardium; [3,4]

the tumor appears to have been present in the heart at the time of intestinal resection, as the angiographic findings suggest, as well as the large size of the valve tumor (9 cm);

tumors of such histology are very uncommon in the duodenum;

histopathological findings of the duodenal specimen are not presented.

At the very least, we believe that it is unknown which of the two sites is primary. For this reason, we believe that the very rare scenario of metastatic sarcoma presenting as a left atrial mass is still not demonstrated convincingly.