What is the classic primary cardiac tumor in adults and where is it most commonly located?

What is the classic primary cardiac tumor in adults and where is it most commonly located?

• A. Cardiac myxoma, most commonly in the left atrium
• B. Cardiac rhabdomyoma, in the right ventricle
• C. Cardiac fibroma, in the interventricular septum
• D. Papillary fibroelastoma, on the aortic valve

Answer: (A)

The most common primary cardiac tumor in adults is a myxoma, and it classically arises in the left atrium from the region of the interatrial septum near the fossa ovalis. This location explains why patients often present with symptoms of mitral valve obstruction in diastole and why embolic events can occur if tumor fragments break off. The lesion is typically a gelatinous, myxoid mass that may be pedunculated and mobile, which can prolapse into the mitral orifice during diastole and mimic mitral stenosis on exam or imaging. Histologically, it shows a myxoid stroma with scattered stellate cells embedded in mucopolysaccharide-rich matrix. Other tumors listed fit different patterns more common in children or on different cardiac structures—for example, rhabdomyoma and fibroma are more typical in pediatric patients and often involve the ventricles or septum, while papillary fibroelastoma usually involves valves.

The most common primary cardiac tumor in adults is a myxoma, and it classically arises in the left atrium from the region of the interatrial septum near the fossa ovalis. This location explains why patients often present with symptoms of mitral valve obstruction in diastole and why embolic events can occur if tumor fragments break off. The lesion is typically a gelatinous, myxoid mass that may be pedunculated and mobile, which can prolapse into the mitral orifice during diastole and mimic mitral stenosis on exam or imaging. Histologically, it shows a myxoid stroma with scattered stellate cells embedded in mucopolysaccharide-rich matrix.

Other tumors listed fit different patterns more common in children or on different cardiac structures—for example, rhabdomyoma and fibroma are more typical in pediatric patients and often involve the ventricles or septum, while papillary fibroelastoma usually involves valves.