Giant Left Atrium Mimicking a Right Thoracic Mass: Case Report

To the Editor: Chronic rheumatic mitral valve disease is increasing in incidence and prevalence in developing countries where rheumatic fever remains a major unresolved health problem.1 Giant left atrium is a rare complication of rheumatic mitral valve disease and does not occur in patients with mitral regurgitation due to other causes.2 We present this patient who was evaluated in our outpatient clinic because of cough and shortness of breath and had a suspicious right thoracic mass image on chest x-ray. A 73-year-old man presented to our outpatient clinic with cough and shortness of breath. He had a history of congestive heart failure. Electrocardiogram showed atrial fibrillation. Physical examination revealed an irregular pulse rate of 55 beats per minute and blood pressure of 110/80 mmHg. No murmur or additional sound was heard upon cardiac auscultation. Other physical examination findings were normal. Chest x-ray revealed cardiomegaly and near-complete opacification of the right mid-to-lower lung zones (Figure 1). A right thoracic mass was suspected, and the patient was seen in the department of pulmonary diseases. Computed tomography (CT) with contrast was performed and revealed a left atrial size of 18.7 by 13.2 cm, filling approximately two-thirds of the right hemithorax with compression atelectasis in the lung parenchyma (Figure 1). Transthoracic echocardiography displayed massive left atrial enlargement with dimensions of 17.0 by 11.5 cm, mild mitral stenosis, and moderate to severe mitral regurgitation due to rheumatic mitral valve disease. The mitral valve was thick and fibrocalcific and made a dome in diastole. There was dense spontaneous echo-contrast but no thrombus in the left atrium. Left ventricular diameters were mildly elevated, and ejection fraction was moderately below normal. Right dimensions were normal. A small leakage from left atrium to right atrium was detected, which was not important hemodynamically. Medical therapy was given, and catheterization and then operation were recommended, but the patient did not accept because he thought he was too old to undergo any intervention. Marked prominence of the right cardiac border with fissured and infiltration in the lung parenchyma on chest x-ray and the giant left atrium (18.7 by 13.2 cm) on computed tomography with contrast. Rheumatic fever predominantly affects the mitral valve. Rheumatic mitral valve disease is common in developing countries and is an important cause of mortality and morbidity.3 Giant left atrium is a rare complication of rheumatic mitral valve disease and does not occur in patients with mitral regurgitation due to other causes.2 The combination of mitral valve disease and atrial inflammation secondary to rheumatic carditis causes left atrial dilation, fibrosis within the wall of the atrium, and disorganization of atrial muscle bundles.3 Atrial fibrillation is always present in patients with giant left atrium. Atrial fibrillation causes diffuse atrophy of atrial muscle and atrial enlargement.4 Giant left atrium can cause thromboembolic events in spite of anticoagulant therapy and recurrent bronchopneumonia, dysphagia, hoarseness, shortness of breath, and cough due to compression of the adjacent organs. In this case, presenting symptoms were cough and shortness of breath. Giant left atrium can be misdiagnosed as a right thoracic mass on chest x-ray or CT without contrast. Physicians can make mistakenly biopsy in these cases. One group of investigators5 performed a biopsy with suspicion of thoracic malignancy (on the CT without contrast) but terminated the procedure when bleeding was encountered. Transthoracic echocardiography must be performed on patients with a right thoracic mass image on chest x-ray. CT with contrast (if there is no allergic reaction) or cardiac magnetic resonance imaging should be performed to discriminate the relationship between the mass and the heart. In addition to medical therapy, different surgical techniques are used to reduce left atrial volume in these patients.6, 7 Although giant left atrium is a rare complication of rheumatic mitral valve disease, it must be included in the differential diagnosis of patients with suspicious right thoracic mass image on chest x-ray or CT without contrast. Physicians in developing countries should be especially aware of this entity. Financial Disclosure(s): None. Author Contributions: Ergun Seyfeli, Sebahat Akoglu, and Fatih Yalcin contributed to study concept and design and preparation of the manuscript. Sinem Karazincir, Ferit Akgul, Tunzale Seydaliyeva, and Mehmet Duru were involved in the study concept and design. Sponsor's Role: No sponsor.