case_images: PMC11319172_01
case_images: (A) TTE, four-chamber subcostal view. Ovoid mass in the right atrium, with echogenicity almost blood-like and calcification areas. (B) TTE, four-chamber apical view. The agitated saline test shows an anechogenic, 40 x 40 mm2, mass in the right atrium implanted in the interatrial septum. No tricuspid valve compromise was observed. (C) TEE, multiplanar image of the interatrial septum (45 ; 135 ). A homogeneous pedunculated mass with a thin covering was implanted in the middle-low interatrial septum with pendulum movement. (D) TEE, multiplanar image of the interatrial septum (45 ; 135 ). The agitated saline test depicts anechogenicity of the hematic mass. TTE, transthoracic echocardiography; TEE, transesophageal echocardiography.
case_images: fcvm-11-1417074-g001.jpg
case_images: PMC11319172_01_fcvm-11-1417074-g001.jpg
case_images: F1
case_images: A cardiologic study plan was initiated with transthoracic echocardiography (TTE), which confirmed the presence of an anechogenic ovoid mass in the right atrium measuring 40 mm x 40 mm2, implanted in the interatrial septum without affecting the tricuspid valve (Figure 1A; Supplementary Video S1). In the study with agitated saline solution, echogenicity of the blood-like mass was evident (Figures 1B,D, Supplementary Video S2). The TEE showed a homogeneous mass covered by a thin layer, implanted in the mid-low septum, and exhibited pendulum movement (Figure 1C, Supplementary Video S3).
case_images: (A,B) ECG-gated CTA, four-chamber view. A mobile, round, homogenous mass is seen adhered to the right lower interatrial septum. (C,D) ECG-gated CTA, sagittal views of the right atrium. A homogeneous, non-contrast-enhancing mass with calcified areas and defined edges is seen in the right atrium. Note the 12 mm pedicle (red arrow) that attaches it to the interatrial septum, near the fossa ovalis. Likewise, the right coronary artery (orange arrow) is seen, which does not provide collateral to the mass. ECG, electrocardiogram; CTA, computed tomography angiography.
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case_images: PMC11319172_01_fcvm-11-1417074-g002.jpg
case_images: F2
case_images: In the study with agitated saline solution, echogenicity of the blood-like mass was evident (Figures 1B,D, Supplementary Video S2). Given these findings, the diagnosis work-up was complemented with an ECG-gated CTA, displaying an ovoid, mobile mass of 35 mm in diameter with homogeneous content and calcified areas with a 12-mm pedicle adhered to the lower atrial septum near the coronary sinus ostium (Figure 2).
case_images: (A) Surgical field. Right atriotomy, with exposure of violaceous, smooth, and shiny mass. (B) Microscopy: fibrous (composed of collagenous layers) cyst wall without epithelial cells. Presence of some lymphocytes. (C) Microscopy: uniform fibrin content with calcification areas (upper region with more intense staining).
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case_images: PMC11319172_01_fcvm-11-1417074-g003.jpg
case_images: F3
case_images: The TEE showed a homogeneous mass covered by a thin layer, implanted in the mid-low septum, and exhibited pendulum movement (Figure 1C, Supplementary Video S3). After the right atriotomy, a violaceous, smooth, tense, and shiny mass was found, suggesting a cyst with bloody content (Figure 3A). Furthermore, fibrin content with areas of calcification was reported (Figures 3B,C), confirming the diagnosis of HEC.