The majority of the cardiac myxomas originate in the atrial wall; ventricular and heart valve myxomas are less common. Myxomas arising from the pulmonary valve are particularly rare. Until now, only eight cases have been reported worldwide through case reports and autopsies [2,3,4,5]. Therefore, there is a lack of information about the age distribution, surgical procedure, and recurrence of these myxomas.
Myxomas of the pulmonary valve and pulmonary arteries are thought to arise in situ or as metastases from distant myxomas . In our case, no myxoma was found at any location other than the primary tumor in the pulmonary valve, and it was considered to be a myxoma originating from the pulmonary valve.
The general complications of myxomas include hemodynamic obstruction, embolization, or constitutional changes. The most common complications of myxoma include systemic embolization of the cerebral arteries, renal arteries, and aorta; pulmonary embolism and pulmonary hypertension; symptoms of cardiac obstruction, such as heart failure, syncope, mitral and tricuspid valve insufficiency, and sudden death; and systemic signs and symptoms, such as malaise, anorexia, fever, arthralgia, anemia, weight loss, and increased levels of C-reactive protein and globulin .
Symptoms specific to right ventricular outflow tract tumors include syncope, arrhythmia, pulmonary embolism, valve dysfunction, and sudden death [7, 8]. The symptoms of the pulmonary valve and pulmonary artery myxomas are similar to those of right ventricular outflow tract tumors. Pulmonary valve myxoma might be misdiagnosed as pulmonary artery embolus, thrombus, or verruca, leading to inappropriate treatment with anticoagulants or thrombolytics [5, 9]. Other differential diagnoses include sarcoma and metastatic tumors .
The treatment for myxoma is surgical resection; however, the recurrence rate is reported to be 13% at 10 years . Nevertheless, the number of cases of pulmonary valve myxoma is small, and the long-term prognosis is unknown .
Reynen suggested the transition from benign to a malignant tumor as an explanation for the recurrence of myxoma . In this case, the myxoma recurred in the pulmonary artery 1 year later. Unfortunately, the patient was already in a very poor respiratory state at the time of recurrence, and a biopsy could not be performed. An autopsy was not conducted respecting the wishes of the family. Therefore, it was not possible to confirm whether the recurrence was due to malignant transformation. Kabbani suggested that the cause of recurrence might be local cytotransplantation of the primary tumor . Therefore, Kabbani recommends a biatrial approach for intracardiac myxomas to ensure resection of the atrial wall, including the tumor, and to prevent intraoperative embolization. Read also suggested that recurrence is caused by systemic embolization of myxoma cells . Furthermore, Read reported that recurrent cardiac myxomas grow more rapidly than primary tumors, and it is important to completely resect the primary tumor during the first surgery. In this case, the tumor partially extended to the posterior wall where a small hole was made during resection. The surgical margins were indistinct, and there was a high possibility of residual tumor in the pulmonary artery wall; hence, an extended resection should have been considered. However, the patient’s condition was highly fragile, and she was unable to walk after fracturing her right femur. She could not tolerate a highly invasive surgery; hence, we chose to perform valve replacement surgery. However, right ventricular outflow tract reconstruction could have been performed to prevent recurrence. The recurrence in this case also suggests that intraoperative embolization may not have been adequately considered. Embolization should have been firmly blocked using gauze or other means during tumor resection to prevent the embolization from falling into the peripheral pulmonary artery.
In general, cardiac myxomas tend to occur in the atrial wall , and there are only a few reports of their occurrence in the heart valve itself. Mitral, tricuspid, and aortic valves account for the majority of reports of myxomas occurring in heart valves, for which valvuloplasty or valve replacement is the procedure of choice, depending on the degree of valve destruction [14,15,16,17,18,19]. Reports of myxomas occurring in the pulmonary artery valve are rare. Therefore, there is a lack of information about the operative technique and prognosis; however, our experience suggests that complete resection at the time of initial surgery and intraoperative embolic prophylaxis are important to prevent a recurrence.