Left Atrial Myxoma Presenting with Splenic Infarct

66 year old female with abdominal pain. Diagnosis? • Xray of the Week

Figure 1. What are the important findings?

Figure 2.

Axial CT - A: Large filling defect in the left atrium. Note the slight enhancement indicating it is a neoplastic mass rather than thrombus, (red arrow) suggesting myxoma. The large size is also compatible with myxoma rather than thrombus. B: Wedge shaped region of lack of enhancement of the spleen suggesting infarction (green arrow).

Discussion:

Cardiac myxomas (CM's) are the most common type of primary neoplasm of the heart. The overall incidence is 0.0017 to 0.02% with most presenting as benign tumor located in the left atrium (60-75%) [1]. Most cases are sporadic without a known etiology with women aged 30-60 years twice as often affected. There is an autosomal dominance inheritance clusters known as Carney syndrome, however, seen in only about 3-10% of all cases [2]. Grossly, CM's present as slimy, friable lesion with smooth or villous surface, the latter having a greater potential for embolic complications [2,3]. They can be sessile, arising from a broad base, or emanate from a stalk or pedicle with average diameter of 5-6 cm and can grow as large as 15 cm [2,5]. Most tumors are pedunculated, located in the atria and found in the region of the fossa ovalis [1,2] as seen in Figure 2A. Younger patients (<40 years old) with non-left atrial location or multiple CM's should be evaluated for “syndrome myxoma,” which are associated with blue nevi, cutaneous lentiginosis, peripheral tumors and endocrine neoplasms [1,4,5].

Clinical symptoms can be caused directly by the tumor from obstruction or in form of embolization. Symptoms are from intracardiac obstruction seen in 52-67% of patients [5]. They are either due to obstruction of the mitral opening or a wrecking-ball effect, resulting in valvular damage leading to mitral regurgitation [4]. They can also present as pulmonary edema, dyspnea, orthopnea, malaise, syncope, and palpitations [1]. The second most common complication is embolization (30-40%) resulting in neurologic sequala (12-30%) or systemic infarction (4.1-23%) of limbs, splanchnic, or coronary circulations [2,5,6,7]. It is important to note that embolic events are not size-related and frequently occur in small tumors as well [3]. Our patient was one of the rare cases presenting with splanchnic infarction as seen in Figures 1 and 2.

Diagnosis of CM's is usually an incidental finding on imaging for other indication in asymptomatic patients [4]. Tentative diagnosis is made on imaging upon exclusion of thrombus or vegetation and presence of a mobile mass attached by stalk or a stalk left after mass had embolized systemically [1]. Echocardiography (Transesophageal > Transthoracic) is the diagnostic test of choice followed by cardiac MRI and CT scans to help better visualize the intracardiac mass for preoperative planning [2,3]. If a stalk or pedunculated mass is not visualized on the echo, MRI can be used to diagnose CM's and help differentiate from thrombus or pseudotumor [3]. On MRI, CM's show heterogenous in cine imaging because of interspersed calcifications or hemosiderin-related artefacts, hyperintense on T2 weighted and isointense on T1-weighted images [2,3]. If MRI is contraindicated or inconclusive, a CT can be performed which would show a left atrial mass with a narrow attachment to the atrial septum and a heterogenous low attenuation [2,3].

CMs can be differentiated from a thrombus on CT by assessing for size, origin, shape, mobility, and prolapse. CMs are larger, originate in fossa ovalis (vs. appendage in thrombi), villous shaped (vs. polypoid in thrombi), greatly mobility, and occurrence of prolapse through mitral valve whereas thrombi never prolapse [8].

Treatment is prompt surgical excision to avoid risk of systemic embolization, cerebral infarction, and sudden death [6]. Overall prognosis is excellent with recurrence rates of 1-5% secondary to incomplete resection, intraoperative tumor seeding or tumor multifocality [2]. The 5-year survival rates are 83% for benign tumors, 30% for malignant neoplasms, and 26% for metastases [5].

References:

1. Bernatchez J, Gaudreault V, Vincent G, Rheaume P. Left Atrial Myxoma Presenting as an Embolic Shower: A Case Report and Review of Literature. Ann Vasc Surg. 2018;53:266.e13-266.e20. doi:10.1016/j.avsg.2018.04.024

2. Jain S, Maleszewski JJ, Stephenson CR, Klarich KW. Current diagnosis and management of cardiac myxomas. Expert Rev Cardiovasc Ther. 2015;13(4):369-375. doi:10.1586/14779072.2015.1024108

3. Colin GC, Gerber BL, Amzulescu M, Bogaert J. Cardiac myxoma: a contemporary multimodality imaging review. Int J Cardiovasc Imaging. 2018;34(11):1789-1808. doi:10.1007/s10554-018-1396-z

4. Maraj S, Pressman GS, Figueredo VM. Primary cardiac tumors. Int J Cardiol. 2009;133(2):152-156. doi:10.1016/j.ijcard.2008.11.103

5. Hoffmeier A, Sindermann JR, Scheld HH, Martens S. Cardiac tumors--diagnosis and surgical treatment. Dtsch Arztebl Int. 2014;111(12):205-211. doi:10.3238/arztebl.2014.0205

6. Frizell AW, Higgins GL 3rd. Cardiac myxoma as a mimic: a diagnostic challenge. Am J Emerg Med. 2014;32(11):1399-1404. doi: 10.1016/j.ajem.2014.08.044

7. Burke A, Jeudy J Jr, Virmani R. Cardiac tumours: an update: Cardiac tumours. Heart. 2008;94(1):117-123. doi:10.1136/hrt.2005.078576

8. Scheffel H, Baumueller S, Stolzmann P, et al. Atrial myxomas and thrombi: comparison of imaging features on CT. AJR Am J Roentgenol. 2009;192(3):639-645. doi:10.2214/AJR.08.1694

Savan V. Patel is a medical student and aspiring diagnostic radiologist at Rowan University School of Osteopathic Medicine in New Jersey. During his time as a medical student, Savan served as the vice president of Inclusion, Diversity, Equity, and Action (IDEA) council. Prior to medical school, he earned MS in Pharmaceutical Sciences with summa cum laude at Rowan University where he published research on novel compounds composed of cyanopyrrolidines and β-amino alcohol scaffolds tested in vitro against Dipeptidyl Peptidase IV (DPP-IV) enzyme, a key regulator of incretin hormones in the management of type 2 diabetes. He graduated magna cum laude from Rowan University where he completed his studies in biochemistry with a minor in biology. Outside of medical school, Savan loves to travel with his wife, cook new cuisines and listen to Bollywood music.

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Kevin M. Rice, MD is the president of Global Radiology CME

Dr. Rice is a radiologist with Renaissance Imaging Medical Associates and is currently the Vice Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015, Dr. Rice and Natalie Rice founded Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. In 2016, Dr. Rice was nominated and became a semifinalist for a "Minnie" Award for the Most Effective Radiology Educator.

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