A cardiac imaging finding shows a heterogeneous pedunculated mass in the left atrium. What is the most likely diagnosis?

A cardiac imaging finding shows a heterogeneous pedunculated mass in the left atrium. What is the most likely diagnosis?

• A. Myxoma
• B. Lipoma
• C. Rhabdomyoma
• D. Fibroma

Answer: (A)

This scenario points to a left atrial myxoma. Myxomas are the most common primary cardiac tumors in adults and classically arise in the left atrium, often from a stalk attached to the interatrial septum near the fossa ovalis. Their pedunculated, mobile nature makes them look like a hanging mass on imaging, and the tissue composition is variable, producing a heterogeneous appearance due to areas of hemorrhage, calcification, and necrosis or gelatinous stroma. This combination—left atrial location, pedunculated attachment, and heterogeneous texture—is the prototypical imaging profile for a myxoma, and it can clinically cause intermittent mitral valve obstruction or embolic phenomena. Other masses don’t fit as well. Lipomas tend to be homogeneous fat-containing lesions, often well circumscribed and not typically pedunculated in the left atrium. Rhabdomyomas and fibromas are more common in children and usually intramyocardial or within the ventricular walls rather than pedunculated atrial masses.

This scenario points to a left atrial myxoma. Myxomas are the most common primary cardiac tumors in adults and classically arise in the left atrium, often from a stalk attached to the interatrial septum near the fossa ovalis. Their pedunculated, mobile nature makes them look like a hanging mass on imaging, and the tissue composition is variable, producing a heterogeneous appearance due to areas of hemorrhage, calcification, and necrosis or gelatinous stroma. This combination—left atrial location, pedunculated attachment, and heterogeneous texture—is the prototypical imaging profile for a myxoma, and it can clinically cause intermittent mitral valve obstruction or embolic phenomena.

Other masses don’t fit as well. Lipomas tend to be homogeneous fat-containing lesions, often well circumscribed and not typically pedunculated in the left atrium. Rhabdomyomas and fibromas are more common in children and usually intramyocardial or within the ventricular walls rather than pedunculated atrial masses.