Cardiac myxoma (CM) is a rare primary benign tumor, accounting for 75% of the total number of women. The most common site is the left atrium, and the vertebral pedicle is often located in the foramen ovale of the atrial septum [5]. About 90% of primary cardiac tumors are benign. According to the literature, the average growth rate of CM is 0.49cm/month, but the actual growth rate is still a controversial issue [6]. A total of 23 cases were included in this study, including 8 males and 15 females, including 7 right CMs and 16 left CMs, consistent with the literature.The cause of CM is unknown.Some studies have shown that CM originates from pluripotent cardiac stem cells [7]. Some studies have shown that CM may be familial and may be an autosomal recessive disease in some families.It is not clear whether the environment or other factors are related to the disease [8].In our study, they can be found in any chamber of the heart, but the frequency is more common in LA (65.22%).Most CM originated from the atrial septum (43.48%), but about 39.13% originated from the outer wall of the atrium or other regions such as the mitral valve. In our study, only a few CM (17.40%) originated from the right superior pulmonary vein, tricuspid valve and right ventricle.
The clinical symptoms of CM are not obvious, and they are often found on physical examination or after acute cerebral infarction.Tumor activity can block the atrioventricular valve and cause obstruction of blood flow, causing abnormal hemodynamics, and severely causing sudden death.At the same time, the tumor is fragile and easy to fall off, which can lead to embolism.Therefore, it should be detected early and operated early, and surgery is an effective treatment method [9].CM may present with various symptoms depending on their location, size, and functional derangements caused by the tumour.The main symptoms of the children in this study included palpitations, cough, syncope and shortness of breath.Neurological symptoms are the second most common finding. These symptoms may be caused by thromboembolic complications of CM.In 30–40% of cases, CM located in left atrium has a risk of systemic embolism[10].In this group, 2 cases were treated in neurology department due to lower limb muscle strength in the early stage, but did not visit our department.One patient went to the neurosurgery department for diagnosis of cerebral infarction and cerebral vasodilation, and one patient was transferred to the respiratory department for cough, expectoration, fever and shortness of breath.Therefore, the early diagnosis of CM is very difficult, and it is easy to be misdiagnosed as other diseases.
Echocardiography is the most important diagnostic method at present; It is non-invasive, and there is no risk of tumor embolism. Echocardiography can easily determine the relationship between the location, size and quality and the intracardiac components[11]. In our series of studies, all CM was initially displayed by transthoracic echocardiography (TTE) and then supplemented by intraoperative transesophageal echocardiography (TEE).
We understand that the tissue of CM in children is fragile, and those with incomplete capsules are more likely to be broken.Therefore, the operation should be gentle during the operation to avoid turning and squeezing the heart.The normal atrial septal tissue where the tumor is attached should be clamped when the tumor is resected.We lift the tumor completely out of the heart cavity to prevent the tumor from breaking.We completely remove the tumor and attached tissues during the operation, and carefully check for any defects after the tumor is removed to prevent tumor fragments from being left.Large resections and patch reconstructions close to the conduction system or mitral valve are technically difficult and dangerous, so resection of tumoural tissues close to these structures may be limited to the subendocardial level.Following the tumor removal from the field, the area should be liberally irrigated, suctioned, and inspected for loose fragments.In this study, 7 cases underwent pericardial repair due to large atrial septal defect, and 3 cases underwent mitral valvuloplasty due to the large base of the tumor, which can easily damage the left atrium and affect the structure of the mitral valve.Two cases with a large tumor expanded the tricuspid annulus, so tricuspid annulus contraction was performed.
The malignant potential of CM was reported in previous studies. Local recurrence and remote metastasis may develop in cases with incomplete resection, intraoperative implantation or embolization, and in cases with malignant transformation potential.Approximately 25% of primary cardiac tumors are malignant, about 75% of which are sarcomas [13].If the complete resection is possible, surgery provides better palliation and can possibly double survival.In our series, the pathological findings of 23 CM was benign in nature.The possibility of recurrence of CM after surgical resection is extremely low, less than 5%, and only a few cases have been recorded[14].In this study, there was 1 case of recurrence 5 years after surgery. The reasons for the recurrence were: incomplete resection of the tumor and residual tumor, and possible tumor implantation in the heart.Therefore, we should pay attention to the postoperative follow-up of patients with CM.The hospital mortality after an excision of CM is reportedly about 5%[15], while in this series it was 4.35%.This is consistent with the literature reports.
So far, some studies have found that 34 protein markers are involved in the histogenesis and development of CM [16].Some potential therapeutic targets such as MUC1, EGFR, FOS and MMP9 have been identified as key targets.This means that drug treatment of CM may become a reality.However, there is no relevant report in clinical practice.Therefore, early diagnosis of CM is particularly important to provide more treatment options.Surgical treatment should be carried out as soon as possible, because as many as 8% of patients may die of obstruction or embolism while waiting for surgery[17].In the clinical practice center with mature minimally invasive experience, thoracoscopic resection is the first choice for surgical treatment of CM [18].However, due to the narrow operation space of thoracoscopic surgery and the need for special equipment and peripheral CPB, clinical practice is difficult, and the safety and clinical effect of thoracoscopic CM resection are still in doubt.Due to the differences in surgical field exposure and observation methods, cardiac tumor resection is incomplete, tumor tissue is easy to fall off during surgery, and it is difficult to completely resect during surgery, which may lead to postoperative recurrence or increase the risk of systemic embolism [19].