A 37-year-old female patient with a past medical history significant for pulmonary embolism secondary to prothrombin factor II mutation in the setting of oral contraceptive use and pregnancy-induced hypertension presented to the emergency department with a chief complaint of palpitations that worsened with exertion. The palpitations had increased in frequency over the past year; on the day of admission, she was found to have frequent premature atrial contractions and brief runs of atrial tachycardia during telemetry monitoring. Transthoracic echocardiogram revealed a left atrial mass measuring approximately 2.0 cm. Cardiac magnetic resonance imaging (MRI) was subsequently performed and confirmed the presence of a large left atrial mass (3.8 x 1.7 cm) with irregular borders that was invading the left atrial wall and extending into the ostia of the superior pulmonary veins. Tissue characteristics included isointense to myocardium on T1 images, hyperintense on T2 images, significant contrast uptake on first pass perfusion, with heterogeneous contrast uptake by delayed enhancement. No pericardial effusion was seen. See Videos 1 & 2 and Figure 1.
Based on the case presentation and cardiac MRI findings, what is the most likely diagnosis?
The correct answer is: C. Angiosarcoma
Tissue diagnosis of this tumor revealed angiosarcoma. Overall, malignant tumors make up about 15% of primary cardiac tumors. Angiosarcomas are the most common among all malignant tumors of the heart and are predominantly seen in the right atrium of middle-aged men. Despite this case's unique presentation of a left atrial angiosarcoma in a young woman, the MRI findings are helpful in pointing toward the most likely diagnosis. MRI is the imaging modality of choice when assessing cardiac tumors. In general, tumors with invasive, irregular borders are more likely to be malignant than their benign counterparts with smooth, well-defined borders and no infiltration of adjacent structures. Furthermore, the heterogeneous contrast uptake seen during delayed enhancement images is particularly telling because very few benign tumors exhibit this finding. Among malignant tumors, angiosarcomas in particular exhibit hyperintensity on T2 images. Though lymphoma may exhibit several similar MRI characteristics, it tends to be located within the intrapericardial space anterior to the right ventricle and not within the cardiac chambers. In general, cardiac MRI is a useful tool to help delineate tumors and guide further therapy.
Orlandi A, Ferlosio A, Roselli M, Chiariello L, Spagnoli LG. Cardiac sarcomas: an update. J Thorac Oncol 2010;5:1483-9.
Fussen S, De Boeck BW, Zellweger MJ, et al. Cardiovascular magnetic resonance imaging for diagnosis and clinical management of suspected cardiac masses and tumours. Eur Heart J 2011;32:1551-60.
Hoey ET, Shahid M, Ganeshan A, Baijal S, Simpson H, Watkin RW. MRI assessment of cardiac tumours: part 1, multiparametric imaging protocols and spectrum of appearances of histologically benign lesions. Quant Imaging Med Surg 2014;4:478-88.