Cardiac myxoma the great imitators: Comprehensive histopathological and molecular approach

Identification of Stem-Like Cells in Atrial Myxoma by Markers CD44, CD19, and CD45

Atrial myxoma is the most frequent tumor arising mainly in atrial septum and its origin remains uncertain. It has been reported that a subpopulation of stem-like cells are present in benign tumors and responsible for tumor initiation and maintenance. In this study, we investigated whether stem-like cells could contribute to the atrial cardiac myxoma. Immunohistology data confirmed that a population of cells bearing the surface markers CD19, CD45, and CD44 resided in a mucopolysaccharide-rich matrix of myxoma. Moreover, we isolated myxoma cells with phase-bright culture method and confirmed that myxoma derived cells express robust level of CD19, CD45, and CD44. Furthermore, the pluripotency of this population of cells also was validated by cardiomyocytes and smooth muscle cells differentiation in vitro. Our results indicate that primary cardiac myxoma may arise from mesenchymal stem cells with the ability to generate tumors with multilineage differentiation. In conclusion, this study for the first time verified that stem-like cells are present in atrial myxoma and this population of cells may have the capacity for myxoma initiation and progression.

Left Atrial Myxomectomy with Intraoperative Severe Mitral Regurgitation and Complicated Postoperative Course - Case Report

Primary cardiac tumors are a rare occurrence with myxomas accounting for about half of the benign tumors. Once diagnosed, surgical resection is the standard of care. Our case describes a female in her 50s who underwent a myxoma resection under cardiopulmonary bypass via biatrial approach. Intraoperatively, the thin septal crux between the wall of the aorta and mitral valve was damaged during resection, requiring stem cell tissue matrix for repair. The patient also developed severe mitral regurgitation suggesting infarct to the left coronary system during resection, subsequently receiving a mechanical mitral valve and a saphenous vein bypass graft. Postoperatively, she developed atrial fibrillation with a left atrial appendage thrombus, heart failure with an ejection fraction of 30%–35%, and a transient ischemic attack. In conclusion, it is important for the clinician to appreciate the possible complications of resection peri and postoperatively.

Risk prediction for emboli and recurrence of primary cardiac myxomas after resection

BACKGROUND

Risk factors for embolism and recurrence of primary cardiac myxoma are not well established. This study aimed to assess the risk factors for embolism and recurrence of cardiac myxoma, as well as the survival of the patients.

METHODS

The medical records of 207 consecutive patients treated for primary cardiac myxoma between September 1988 and October 2014 were retrospectively analyzed. All diagnoses were pathologically confirmed. Data were collected to identify the risk factors influencing the prognosis.

RESULTS

Mean age at surgery was 44.2 ± 15.8 years. Operative mortality (within 30 days of the surgery) occurred in seven patients. Mean follow-up was 9.35 ± 6.55 years. Embolism occurred in 32 (15.5 %) patients before surgery. Multivariate analysis indicated that small (≤ 4.5 cm) myxoma (OR = 5.14; 95 % CI, 2.30-11.94; P < 0.0001) and soft, gelatinous myxoma (OR = 5.84; 95 % CI, 1.91-25.61; P = 0.001) were independently associated with the occurrence of embolism. Ten patients experienced recurrences. After excluding the patients who died within 30 days of surgery, survival was 92.7 % at 10 years. Age, sex, tumor size, cardiopulmonary bypass duration, aortic cross clamp duration, tumor appearance, and pre-operative embolism were not associated with early mortality. Multivariate analysis showed that multicentric myxomas were independently associated with recurrence (OR = 9.45, 95 % CI, 2.15-41.3, P = 0.004).

CONCLUSIONS

The surgical resection of primary cardiac myxoma is associated with excellent long-term survival. Tumors ≤ 4.5 cm and soft tumors were independent risk factors for embolism. Multicentric cardiac myxoma was an independent risk factors for recurrence of myxoma.

Clinical Features and Surgical Results of Right Atrial Myxoma

BACKGROUND

We retrospectively analyzed 367 patients receiving surgical resection of cardiac myxomas in our center over six years, and analyzed the incidence and surgical results of 28 cases of right atrial myxomas. We also compared the age, gender, and attached sites between left atrial myxoma and right atrial myxoma.

METHODS

Between January 2007 and December 2012, 28 patients with right atrial myxomas underwent surgical resection. There were 16 males and 12 females. The mean age was 47.77 ± 13.20 years (range: 8.00-79.00 years). Associated cardiac lesions included moderate and severe tricuspid regurgitation in four, coronary atherosclerotic heart disease in five, and pulmonary embolism in one. Twenty-seven patients (96.43%) were followed from 26 to 94 months (mean 55.78 ± 21.10 months).

RESULTS

There was no early death after operation. The incidence of right atrial myxomas among sporadic cardiac myxomas was 7.89%. One patient died of lung cancer 34 months after myxoma resection. Two patients underwent coronary artery stent implantation due to coronary atherosclerotic heart disease during the follow-up period. One patient underwent myxoma resection due to recurrence in the left atrium four years after the first operation. There was no significant difference in the age between left atrial myxoma and right atrial myxoma (p > 0.05). There was a significant difference in the gender between left atrial myxomas and right atrial myxomas (p < 0.05). The most common attached sites of left atrial myxomas and right atrial myxomas are the atrial septum.

CONCLUSIONS

Surgical resection of the right atrial myxoma results in good clinical outcomes and a decreased incidence of recurrence.

[Histopathological and immunohistochemical features of cardiac myxomas]

Mixomas are the most common primary cardiac tumors with an estimate incidence of 0,5-1 per 10(6) individuals per year. These tumors have generated interest due to their unique location (left side of the atrial septum near the fossa ovalis), variable clinical presentation and undefined histogenesis. Most cardiac myxomas occur sporadically while approximately 10% of diagnosed cases develop as part of Carney complex. This neoplasm is of uncertain histogenesis, however, endothelial, neurogenic, fibroblastic, and cardiac and smooth muscle cells differentiation has been proposed, and rarely glandular differentiation has been observed. Recently, due to the expression of certain cardiomyocyte-specific factors, an origin of mesenchymal cardiomyocytes progenitor cells has been suggested. Histologically cardiac myxomas are mainly composed of stellated, fusiform and polygonal cells, immersed in an amorphous myxoid matrix. Immunohistochemically some endothelial markers, such as CD31, CD34, FVIIIAg, are present. Positive staining has also been reported for S-100 protein, calretinin, vimentin, desmin, smooth muscle myosin, CD56, α1 antitrypsin and α 1antichymotrypsin. Surgical resection is currently the only treatment of choice. We present in this article a histopathological and immunohistochemical review of cardiac myxomas.

Left atrial cardiac myxoma. Two unusual cases studied by 3D echocardiography

We describe two patients with cardiac tumors in the left atrium, which by their association and histopathological lineage, are extremely rare. The clinical, echocardiographic and pathological findings were analysed. The first case was asymptomatic, but in the control studies of colon adenocarcinoma, an intracardiac mass was found by chest computed tomography (CT). A transesophageal 3D (TEE 3D) echocardiogram revealed a left atrial mass attached to the interatrial septum. The mass was surgically removed and histopathologic findings showed myxoma. The second had history of chronic intermittent diarrhea. A thoraco-abdominal CT showed a left atrial mass. The TEE 3D echocardiography reported an intracardiac mass attached to the roof of the left atrium. The mass was surgically removed and the histopathogical findings showed a myxoma, with dystrophic ossification and extramedullary hematopoiesis. TEE 3D echocardiography provides an acceptable morphological characterisation of intracardiac masses, with good correlation with surgery.

Treating cardiac myxomas: a 16-year Chinese single-center study

AIMS

Currently, myxoma is the most common type of primary cardiac tumor diagnosed. This article describes the experience over the past 16 years with cases of cardiac myxoma in Chinese patients and elucidated the differences between solid and papillary myxomas.

METHODS

The clinical details of 68 patients with cardiac myxomas who underwent surgery between January 1996 and January 2012 at our center were retrospectively analyzed.

RESULTS

The left atrium was the primary tumor site in 88% of the patients included in this study. The most common implant site was the interatrial septum (69%), especially for patients with solid tumors. Common clinical symptoms included dyspnea and palpitation, whereas embolic events occurred in 12 patients. Myxoma resection involved a midline sternotomy utilizing cardiopulmonary bypass. According to pathological classification, solid myxomas were present in 28 patients (47%), whereas papillary myxomas were detected in 40 patients (53%). In the solid group, arrhythmias and a larger tumor volume were more common. Correspondingly, in 97.4  ±  2.5% of cases, secondary surgery was not needed after 10 years. Overall, the actuarial survival for patients undergoing surgical excision of myxoma was 98.4  ±  1.6% at 5 years and 96.0  ±  2.8% at 10 years.

CONCLUSION

Solid myxomas were associated with more arrhythmias, a larger tumor volume, implantation in the interatrial septum, and a need for concomitant surgery compared with papillary myxomas. Further studies should determine whether serum or histological markers could be routinely used in combination with echocardiograms, MRI and computed tomography for the predictions of recurrent myxomas during annual follow-up examinations.

Molecular basis of cardiac myxomas

Cardiac tumors are rare, and of these, primary cardiac tumors are even rarer. Metastatic cardiac tumors are about 100 times more common than the primary tumors. About 90% of primary cardiac tumors are benign, and of these the most common are cardiac myxomas. Approximately 12% of primary cardiac tumors are completely asymptomatic while others present with one or more signs and symptoms of the classical triad of hemodynamic changes due to intracardiac obstruction, embolism and nonspecific constitutional symptoms. Echocardiography is highly sensitive and specific in detecting cardiac tumors. Other helpful investigations are chest X-rays, magnetic resonance imaging and computerized tomography scan. Surgical excision is the treatment of choice for primary cardiac tumors and is usually associated with a good prognosis. This review article will focus on the general features of benign cardiac tumors with an emphasis on cardiac myxomas and their molecular basis.

Tricuspid valve obstruction and right heart failure due to a giant right atrial myxoma arising from the superior vena cava

Myxomas are the most common primary cardiac tumors. The cardiac myxomas are mostly diagnosed within the atria, and only a few such tumors are reported to have arisen from atrioventricular valves or pulmonary vessels. The authors here present a case of 59-year-old Chinese woman who was hospitalized for exacerbating symptoms of tricuspid stenosis and right heart failure. Echocardiography revealed a giant right atrial myxoma arising from an extremely rare site, the anterior wall of the superior vena cava. With the aid of transesophageal echocardiography, the surgical resection was performed successfully with the patient achieving complete recovery.