Diagnosis and Management of Giant Ventricular Fibroma in a 14-Month-Old Toddler: Insights from Cardiac MRI

A 14-month-old toddler with a heart murmur was admitted to the Department of Pediatric Cardiology. Physical examination revealed a blood pressure of 105/60 mmHg, a pulse of 100/min, and a 2/6° mid systolic ejection murmur in the left upper sternal area. The patient’s electrocardiogram was normal. A transthoracic echocardiographic examination relieved a massive (5×4.8×5 cm) homogeneous, hyper echogenic mass extending from the basal to the mid-segment and covering the full anterior half of the ventricle cavity ([Fig. 1a]). The mass was suspected of either benign rhabdomyoma or fibroma. Then, the patient was referred to the Department of Radiology for a cardiac MRI examination to make a differential diagnosis. On MRI, the cine images showed a single well-defined tumor in the myocardium involving the interventricular septum on the left ventricular wall that was isointense to the myocardium. The tumor was isointense in T1- and T2-weighted turbo spin-echo axial images without signal loss with fat suppression. In T2-weighted images, there were also heterogeneous hypo intense areas in the center of the tumor ([Fig. 1]b, [1]c). There was no first-pass enhancement (1D). However, in the late contrast-enhanced scans obtained 10 minutes after gadolinium administration, the mass had intense peripheral enhancement with no enhancement in the center ([Fig. 1e]). With these characteristic findings, the mass was diagnosed as a ventricular fibroma. The Cardiac MRI also showed that the tumor extended the left ventricular outflow tract, causing a mild dynamic outflow gradient ([Fig. 1f]). Cardiovascular surgery was consulted. It was decided that the surgical operation should not be performed due to the existence of massive intramural myocardial involvement; however, if the cardiac outflow obstruction occurs and the obstruction induces severe hemodynamic deterioration or arrhythmia in the infant’s heart, surgical intervention would be a necessity to treat cardiac fibroma.

Fig. 1 a. Transthoracic echocardiography showing a huge (5×4.8×5 cm) homogeneous mass extendingfrom the basal to mid segment and covering full anterior half of ventricle cavity. b. T1-weighted axial images showing the tumor is isointense with myocardium. c. T2-weighted axial images showing the tumor is isointense with myocardium and having heterogeneous hypointense areas in the center of tumor (arrow). d. In the first-pass enhancement short axis images showing the tumour had no enhancement. e. In the left ventricule outflow tract cine images showing flow jet during systole at aorta (arrow). f. In the late contrast-enhanced short axis images showing the tumour had intense peripheral enhancement with no enhancement in the center.

Cardiac MRI is an effective method to characterize tissue and improves the diagnostic accuracy. It is important to distinguish cardiac fibroma and isolated giant rhabdomyoma. On cardiac MRI, both tumors are well-marginated from the surrounding myocardium that appears benign. Furthermore, a benign tumor with limited vascularity, rather than a malignant tumor with abundant vascularity, is reflected by a hypointense signal on first-pass perfusion imaging as compared to the surrounding myocardium. Furthermore, cardiac fibroma is the only tumour that exibits iso signal intensity on T1-weighted imaging and low-signal intensity on T2-weighted imaging. This indicates low water content, which is different from malignant tumours and many other benign tumours (Teis A et al., Circulation 2011; 124: 1481–1482). An abundance of fibrotic tissue in cardiac fibroma is shown by the hyperintensity of the entire mass on LGE. Therefore, tissue characterization using MRI can provide additional information to diagnose cardiac fibroma non-invasively without the need for tissue biopsy and can expedite preventative surgery to avoid sudden death (Kimura A et al., Eur Heart J Case Rep 2020 4: 1–5).

In conclusion, we want to contribute our experience with a case of probable myocardial fibroma diagnosed with magnetic resonance imaging (MRI) that underlines the diagnostic importance of the late enhancement pattern to differentiate myocardial fibroma from rhabdomyoma.

Publication History

Article published online:
07 February 2025