Multiple Peripheral Pulmonary Artery Aneurysms in Association With a Right Atrial Myxoma
A 48-year-old woman was admitted with complaints of cough with blood in sputum for the last 3 weeks. She had experienced exertional dyspnea for 3 years. A chest radiograph showed many nodules in the bilateral lungs, raising the possibility of pulmonary metastases (Figure 1). Transthoracic echocardiography revealed a moderate echogenic mobile mass measuring 3.1×2.5 cm in the right atrium (Figure 2). This mass was attached to the interatrial septum by a pedicle. The ventricles, atria, aorta, and pulmonary artery were normal in size. There was no tricuspid and pulmonary regurgitation. Unenhanced computed tomography showed many round and ovoid nodules with diameters of <2.5 cm in the bilateral lungs (Figure 3). Computed tomography pulmonary angiography showed a lobular right atrial mass attached to the interatrial septum by a pedicle (Figure 3). There were many (>60) saccular or fusiform aneurysms in the peripheral pulmonary arteries, producing a tree-in-bud sign (Figure 4). Most of the aneurysms and some pulmonary arteries had thrombi. The patient underwent resection of the right atrial tumor. Grossly, the lobular pedunculated tumor had a gelatinous cut surface. Microscopically, the tumor cells scattered in abundant myxomatous stroma. Moderate inflammatory cells (hemosiderin-laden macrophages, macrophages, lymphocytes, and plasma cells) were present. Myxoma was confirmed by pathology (Figure 5). The patient’s symptoms improved after operation. A follow-up computed tomography pulmonary angiography performed 3.5 years after cardiac surgery showed that most of the pulmonary aneurysms had become smaller with disappearance of the thrombi and several aneurysms became slightly larger (Figure 6).
About 35% of left-sided myxomas can embolize to systemic circulation, usually to the brain, kidneys, and lower extremities, and 10% of right-sided myxomas embolize to the pulmonary circulation.1 The propensity of cardiac myxomas to embolize is related to tumor structure, with gelatinous myxomas being more likely to embolize than firm lesions. Tumor emboli can cause aneurysms.2 Aneurysms caused by left-sided cardiac myxomas usually occur in the brain. The imaging features of the cerebral aneurysms include fusiform or saccular shape, multiplicity, and distal location.3 The pathogenesis of these aneurysms is unclear. Direct embolization of fragile and myxomatous materials to the lumen of the vessel, with invasion of tumor cells into the endothelium and disruption of the internal elastic lamina, may result in dilation of the disrupted vascular wall and aneurysmal formation.2 Pulmonary artery aneurysms caused by a right-sided cardiac myxoma have rarely been described.4 Having so many aneurysms (>60) arising from the periphery pulmonary arteries in association with a right atrial myxoma is extremely rare. There is no definitive treatment of these aneurysms. Removal of the atrial myxoma may be helpful for preventing aneurysmal growth and reducing the risk of pulmonary embolism.
- © 2016 American Heart Association, Inc.