Article ID: CJ-24-0006
An 84-year-old man with a history of stable angina underwent follow-up transthoracic echocardiography, which detected an abnormal mass in the left atrium (Figure A; Supplementary Movie 1) that was not observed 2 years earlier (Figure B). Computed tomography (CT) also showed the mass; however, a previous CT revealed only mild thickening of the atrial wall (Figure C,D). Transesophageal echocardiography was conducted for a detailed examination and showed the mobile mass attached to the atrial septum (Figure E,F; Supplementary Movie 2). Considering sinus rhythm on the electrocardiogram, the attachment site, and the morphology, a left atrial myxoma was highly suspected. Robot-assisted tumor resection was performed (Figure G), and the tumor was finally diagnosed as a myxoma with hemosiderin deposition by pathological examination (Figure H).
(A) The mass was incidentally detected by transthoracic echocardiography (TTE). (B) TTE showed no evidence of a mass 2 years earlier. (C) Previous computed tomography (CT) demonstrating only mild thickening of the left atrial wall. (D) CT showing the mass at the atrial septum. (E) Transesophageal echocardiography showing the mass attached to the atrial septum. (F) Three-dimensional image of the highly mobile mass. (G) The tumor was 20 mm in diameter with a smooth and jelly-like surface. (H) Pathological examination (hematoxylin-eosin stain) led to a diagnosis of myxoma with hemosiderin deposition.
This case presents a rare opportunity to observe the fast growth of a myxoma, as documented by using echocardiography and CT.
The mechanism of fast-growing myxomas is attributed to interstitial hemorrhage from tumor microvessels.1 In this case, the pathological examination revealed hemosiderin deposition, suggesting that the myxoma grew rapidly within a relatively short period.
Retrospectively, the initial CT scan may have shown thickening of the left atrial septal wall; however, predicting the development and growth rate of a myxoma from such findings remains challenging.
The authors have no conflicts of interest to disclose.
Supplementary Movie 1. Image on transthoracic echocardiography.
Supplementary Movie 2. Three-dimensional image of the mass.
Please find supplementary file(s);
https://doi.org/10.1253/circj.CJ-24-0006
