Multimodal Imaging of Papillary Muscle-Origin Left Ventricular Myxoma

Cardiac myxomas most commonly originate in the left atrium, whereas occurrences in the ventricles are rare, accounting for only 3% to 4% of cases. Their pseudoinvasive growth, which can mimic malignancy, poses significant diagnostic challenges.

A 49-year-old asymptomatic man underwent transthoracic echocardiography, revealing a 27.5 × 16.5 mm moderately echogenic mass in the midlateral left ventricle, adjacent to the anterior papillary muscle. Further examination showed the mass with low-density margins merging with the chordae tendineae on computed tomography (54 HU), homogeneous T2 hyperintensity with delayed "cloud-like" enhancement on cardiac magnetic resonance imaging, and moderate metabolic activity (SUV_max = 7.8) on positron emission tomography/computed tomography. Histopathological examination confirmed the mass as a benign myxoma with pseudoinvasive entrapment of the papillary muscle. Subtotal resection was performed, successfully maintaining mitral valve integrity.

This case demonstrates the value of integrated imaging techniques in differentiating pseudoinvasive cardiac myxomas from malignant tumors, thereby enhancing diagnostic approaches for ventricular masses.

Multimodal imaging is crucial for diagnosing cardiac tumors located in atypical regions. Recognizing benign pseudoinvasive patterns is key to avoiding unnecessary radical surgery.