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At the age of 21 a woman underwent thoracotomy for removal of a left atrial myxoma. Her mother and sister had both died suddenly, at ages 31 and 19; necropsy in the sister had revealed a left atrial myxoma. 12 years after operation, the patient complained of shortness of breath, palpitations, and a persistent ache and paraesthesiae in the right fore-arm and fingers. On examination she had a systolic murmur at the left parasternal edge, and investigations showed reappearance of the tumour, this time in the right atrium in the region of the fossa ovalis. A sternotomy was performed and a 10 cm long and 1 cm diameter mass of myxoma arising from the limbus was widely excised with the fossa ovalis. The defect was repaired with Dacron. 11 years later, recurrence of the tumour was discovered in the right ventricle with involvement of the tricuspid valve, after the onset of bilateral claudication. A sternotomy was performed again, and an enormous tumour was found in the right ventricle with involvement of the tricuspid valve and several papillary muscles. The tumour was excised with the tricuspid valve, which was replaced with a Carpentier—Edwards xenograft. A 2 cm tumour in the left atrium was also excised, the defect being repaired with a patch. The left ventricle was explored but no tumour was found on the mitral or aortic valves. 16 years later a cardiac murmur was heard on routine follow-up and transoesophageal echocardiography revealed a 3 cm lesion, this time on the posterior mitral valve leaflet. The tumour was very mobile and was flipping in and out of the left atrium during diastole and systole (Figure 1). Sternotomy was done again, the tumour was excised and the mitral valve was preserved. Histology confirmed myxoma tissue on each recurrence.
Even in families, multiple recurrences of this kind have seldom been reported3. Myxomas can develop in any chamber of the heart, the most common site being the left atrium; often they are bilateral. In families the disorder is transmitted in autosomal dominant fashion and has a predeliction for young women4. It can also be a component of Carney's complex, a familial multiple neoplasia/lentiginous syndrome. A family history should be sought in all patients with cardiac myxoma.
Cardiac myxomas sometimes present with valvular obstruction, which can give a picture of mitral disease or right heart failure. Neurological deficits tend to arise when the myxoma gets infected and the friable tumour tissue embolizes to the brain or the limbs. Some myxomas are sufficiently mobile to move through the atrioventricular valves during diastole, exerting a ‘wrecking ball’ effect that damages the valve leaflet and causes anaemia and a high erythrocyte sedimentation rate. Constitutional symptoms such as fever, malaise and weight loss can result from elaboration of the cytokine interleukin-6. Right bundle block has been recorded in as many as one-third of cases. The most useful diagnostic investigation is echocardiography, though large vegetations, an infected thrombus, or even mitral valve prolapse can produce patterns that are indistinguishable from myxoma. Transthoracic echocardiography is the most commonly used, but transoesophageal echocardiography has better specificity and sensitivity.
The recurrent myxomas can be divided into four groups—inadequate resection, familial, totipotent multicentricity and metastatic recurrence. Multifocal disease is frequent in the familial setting4. Recurrence has been associated with abnormal DNA ploidy in up to 40% of the patients. Indeed, DNA testing of all patients with cardiac myxoma may prove to be the best predictor of the likelihood of recurrence5.
Surgical excision must be done as soon as possible after diagnosis because of the high risk of valve obstruction or systemic embolization. Ideally, the tumour should be excised with a large cuff of atrial septum. Valve replacement may be necessary, and there is a report of cardiac transplantation in a woman with recurrent disease6.