Background
Although transthoracic echocardiography and two-dimensional transesophageal echocardiography (TEE) identify cardiac myxomas with high sensitivity, anatomic and morphologic information is often incomplete. Real-time three-dimensional (3D) TEE is increasingly being used in general clinical practice. However, the use of real-time 3D TEE for the assessment of atrial myxomas has not been described.
Methods
This case series of 10 patients with left atrial myxomas undergoing two-dimensional and real-time 3D TEE.
Results
Correlative pathologic findings demonstrate that 3D imaging accurately identifies these tumors and provides detailed morphologic description of the tumors, which may have clinical importance.
Conclusions
Because the 3D TEE is real time and can be performed preoperatively in the operating room, the surgeon may gain a better understanding of the nature and location of the tumor.
Left atrial myxoma was first identified by M-mode echocardiography in 1969. Subsequently, echocardiography has been the most widely used technology for its diagnosis. The advent of two-dimensional (2D) transthoracic echocardiography has resulted in detecting cardiac myxomas with high sensitivity, but detailed anatomic information is often lacking. To more accurately delineate the structure and site of attachment as well as to detect potential satellite lesions, 2D transesophageal echocardiography (TEE) is typically needed. Even with the perceived high accuracy of 2D TEE, there are several reports of myxomas being misdiagnosed as thrombi as well as thrombi that have been misdiagnosed as myxomas. The distinction between thrombus and myxoma is very important. Whereas the treatment for thrombus is anticoagulation, the treatment of choice for myxoma is complete surgical excision, which includes a generous excision of the interatrial septum at its site of attachment to prevent recurrence.
Real-time three-dimensional (3D) TEE (RT3DTEE) is increasingly being used in general clinical practice. However, the use of RT3DTEE for atrial myxomas has not been described. We report 10 patients with left atrial myxomas who underwent intraoperative 2D TEE and RT3DTEE, with the related pathologic findings.
Methods
Patient Selection
Ten consecutive patients referred for cardiac surgery for left atrial tumor removal were studied ( Table 1 ).
| Case | Age (y)/Gender | Symptoms | Findings on 2D TEE | Findings on RT3DTEE |
|---|---|---|---|---|
| 1 | 53/F | No | Many echolucent areas creating appearance of a papillary tumor | Nonpapillary; pale homogenous segments; stalk better identified |
| 2 | 25/M | Yes (brain infarcts) | Attached with broad base close to posterior atrioventricular groove; multiple excrescences | Distinct stalk identified; multiple excrescences |
| 3 | 62/M | No | Very homogeneous with very smooth surface | Irregular surface and less homogeneous |
| 4 | 46/M | No | No stalk identified; homogeneous body | Stalk identified; central hypoechoic area |
| 5 | 62/M | No | Homogeneous with smooth surface | Lobular surface |
| 6 | 34/M | No | No distinct stalk; smooth surface | Stalk; lobular surface |
| 7 | 31/F | Yes (near syncope) | Indistinct stalk | Bright, smooth stalk; “en face” view of tumor and mitral valve orifice |
| 8 | 53/F | No | Broad attachment to fossa | Thick, distinct stalk |
| 9 | 67/M | No | Heterogeneous, very mobile tumor | Improved visualization of the morphology of the proximal tumor, connecting “stalk,” and distal portion |
| 10 | 48/F | Yes (positional shortness of breath) | Mobile tumor with smooth surface and echolucent areas within the body | Lobulated tumor without echolucent areas; “en face” view of tumor and mitral valve orifice |
Echocardiography
Each patient underwent simultaneous 2D TEE and RT3DTEE at the time of cardiac surgery by one of four board-certified echocardiologists using an iE33 system (Philips Medical Systems, Andover, MA) with 2D and 3D transesophageal echocardiographic imaging capacity. All images were stored digitally and were interpreted with attention to the size and location of the tumor, the presence or absence of a stalk, the smoothness of the surface (smooth vs lobulated), and the presence or absence of papillary excrescences. The tumor was described as homogenous or heterogeneous according to the absence or presence of echolucent areas. The still images for the figures were created from bitmap images from the saved digital files. The 3D images were presented first as the full images with not only the tumor but also the relation to the surrounding structures shown. Then the image background was subtracted, and only the tumor was shown to compare with the gross pathologic images of the excised tumors.
Pathology
All patients had microscopic and gross pathologic description performed by a single cardiac pathologist unaware of the echocardiographic findings.
Results
Case 1
A 53-year-old woman with a history of intravenous drug abuse and a long hospital course underwent transthoracic 2D echocardiography and color and Doppler to evaluate left ventricular function. The left atrium was found to be mildly enlarged, with a moderately large mobile (2.2 × 2.1 cm), mildly heterogeneous mass possibly originating from the anterior left interatrial septum. On 2D TEE, the mass was seen more clearly to be heterogeneous, with few papillary excrescences. The body of the tumor had multiple echolucent, areas creating a multilobular, papillary appearance ( Figure 1 A). The mass originated from the superior aspect of the left atrial septum and measured 2.7 cm. With the administration of perflutren, there was contrast enhancement of the mass. Although the use of contrast for this purpose is off label, the finding is consistent with the mass being a vascular structure. As part of the intraoperative assessment, live 3D TEE was performed ( Figures 1 B and 1 C). These images revealed a highly mobile 1.8 × 3.0 cm mass attached by a stalk to the superior aspect of the fossa ovalis and the dome of the left atrium. Although the mass was heterogeneous in nature, and few papillary excrescences were present on the surface, there was no appearance of a papillary or multilobular body. The site and size of the tumor were confirmed by the surgeon. On gross pathologic examination, the mass was pink-tan, demonstrating fibrosis alternating with gelatinous texture. The mass measured 1.5 × 2.2 × 3.5 cm ( Figure 1 D). As seen in Figures 1 C and 1 D, the pale homogeneous areas on RT3DTEE correlated with the pale fibrotic areas, while the areas with a more heterogeneous texture corresponded to the gelatinous segments. Upon sectioning, the cut surface appeared pink-tan with focal areas of hemorrhage.
Case 2
A 25-year-old man presented with amnesia after a motor vehicle accident. He was found on brain magnetic resonance imaging (MRI) to have multiple scattered infarcts of varying age consistent with embolic strokes. Two-dimensional TEE revealed a heterogeneous mass measuring 3 × 4 cm attached to the posterior atrioventricular groove adjacent to the coronary sinus ( Figure 2 A, Video 1 [view video clip online]). Intraoperatively, a large, very heterogeneous mass was identified by RT3DTEE ( Figure 2 B, Video 2
[view video clip online]). The 3D images identified a dense stalk as well as the papillary nature of the tumor, with a large number of papillary excrescences and areas of hemorrhage and an overall very heterogeneous appearance, both of which were confirmed by pathology. Although 2D TEE had demonstrated the multiple excrescences, it failed to identify the stalk. On surgical excision, the mass was so friable that it came off in multiple pieces and could not be resected as a solitary tumor. On gross pathologic examination, the tissue was described as tan-white friable papillary tumor pieces with focal areas of hemorrhage, while the stalk was firm and homogenous, consistent with the findings on RT3DTEE. The heterogeneous nature of the tumor was also found on microscopy where typical lepidic (myxoma) cells admixed with mononuclear cells as well as necrotic regions were seen. Platelets, fibrin, red blood cells, and neutrophils were described, consistent with a recent clot ( Figure 2 C).
Case 3
A 62-year-old man with a history of prostate carcinoma and renal cyst underwent computed tomography (CT) of the abdomen. Incidentally, a left atrial mass measuring 3.3 × 4.2 cm was visualized. Two-dimensional transthoracic echocardiography demonstrated a 3.1 × 3.9 cm left atrial mass attached to the interatrial septum near the fossa ovalis, presumed to be a left atrial myxoma. TEE using 2D and real-time 3D imaging performed at the time of surgery demonstrated a large spherical mass attached to the left atrial septum ( Figures 3 A– 3 C). Two-dimensional TEE and RT3DTEE showed the mass as round with distinct borders. There were no papillary excrescences, and the mass was, particularly on 2D TEE, very homogenous, with a uniformly distributed speckled surface pattern (“salt and pepper” appearance). The tumor had a very smooth surface on 2D TEE, whereas RT3DTEE visualized the surface as slightly more irregular, with a more heterogeneous appearance but still with distinct borders. Gross pathologic examination revealed a rubbery white-tan hemorrhagic mass measuring 2.5 × 3.5 × 4.0 cm ( Figure 3 D), without necrotic areas. Microscopy demonstrated typical myxoma cells in an acellular myxoid stroma.
Case 4
A 46-year-old man was admitted with small bowel obstruction. Abdominal CT demonstrated an incompletely visualized left atrial mass. On transthoracic echocardiography, the mass was mobile, measuring 2.2 × 2.4 cm and seen along the interatrial septum in the left atrium. Two-dimensional TEE demonstrated a left atrial mass with a smooth surface ( Figure 4 A). Although a stalk was not identified, the mass was visualized at the site of the fossa ovalis. RT3DTEE showed a rounded mass with a lobular surface, without any papillary excrescences, attached by a stalk to the fossa ovalis. A central area of hypoechogenicity was noted ( Figures 4 B and 4 C). On gross pathologic examination, the mass was noted to have a tan-yellow appearance, with a central area of necrosis corresponding to the central hypoechoic area seen on RT3DTEE ( Figure 4 D). On microscopy, nests of myxoma cells formed a 3D aggregate with a central luminal space. The extracellular matrix was rich in mucopolysaccharides but relatively acellular.
Case 5
A 62-year-old asymptomatic man underwent routine transthoracic echocardiography demonstrating a left atrial mass consistent with a myxoma located near the fossa ovalis. Two-dimensional TEE and RT3DTEE were performed at time of minimally invasive surgery for excision of the tumor. Both 2D TEE and RT3DTEE revealed a round mass attached with a stalk to the fossa ovalis on the left atrial side of the septum. On 2D TEE, the mass appeared homogeneous with a smooth surface, whereas RT3DTEE demonstrated a more lobular surface pattern. There were no papillary excrescences or echolucent areas ( Figures 5 A– 5 C). By gross pathology, the mass was noted to be well described, measuring 1.9 × 2.0 × 3.5 cm and consisting of pale tan-red gelatinous polypoid tissue ( Figure 5 D). No necrotic or hemorrhagic areas were described by pathology, similar to the lack of echolucent areas on RT3DTEE.
Case 6
Abdominal CT was performed in a 34-year-old man for evaluation of hernia, revealing a masslike lesion in the left atrium. Further workup with transthoracic echocardiography revealed a very large mass (4.8 × 5.1 cm) likely attached to the septal wall of the left atrium. Intraoperative 2D TEE and RT3DTEE were performed, showing a large pedunculated mass measuring 4.0 × 4.5 × 5.8 cm attached to the inferior portion of the left atrial septum ( Figures 6 A– 6 C). On 2D TEE, the mass was seen as homogenous with a smooth surface and appeared attached to the inferior portion of the septum, although a distinct stalk was not identified. RT3DTEE demonstrated a broad stalk that was pale and smooth compared with the body of the tumor, which was visualized as homogenous with a lobular and irregular surface. The mass was described by gross pathology as a slightly lobulated, gelatinous-myxoid, hemorrhagic mass with a pale-tan area at the attachment site ( Figure 6 D) Microscopy revealed hypocellular tissue containing scattered blood vessels and hemosiderin deposits. No significant necrosis was noted.
Case 7
A 31-year-old, previously healthy woman was seen in cardiology consultation for evaluation of atypical chest pain and postural dizziness. Transthoracic echocardiography demonstrated a very large mass in the left atrium measuring 2.8 × 3.5 cm, consistent with left atrial myxoma. Two-dimensional TEE and RT3DTEE were performed at time of surgery. Both 2D TEE and RT3DTEE demonstrated a large, homogenous, and smooth-appearing round mass attached to the fossa ovalis via a short, broad stalk ( Figures 7 A– 7 C, Videos 3–5 [view video clips online]). Although the stalk on 2D TEE appeared similar in echogenicity as the body of the mass, 3D imaging demonstrated the stalk as bright and smooth. The mass prolapsed through the mitral valve and obstructed mitral inflow during diastole, accounting for the patient’s lightheadedness and presyncope symptoms. Gross pathology confirmed the homogenous nature of the mass, with only very scant areas of hemorrhage ( Figure 7 D).
