Baylor Scott & White The Heart Hospital – Plano, TX, USA
Clinical History:
A 39-year-old female with no significant medical history presented to the emergency room with intermittent substernal chest pain and palpitations. Initial hospital evaluation for acute coronary syndrome was unremarkable. During subsequent outpatient cardiology evaluation, a coronary CT angiogram revealed a 7 x 5.7 cm ovoid mass on the lateral wall of the left ventricle (LV), compressing the LV cavity (Figure 1). The mass had a lower attenuation (62 Hounsfield Units) when compared to myocardium (93 Hounsfield Units). Given the concerning appearance of the LV mass, the patient was referred for further evaluation with cardiovascular magnetic resonance (CMR).
 Figure 1: Coronary CTA with large ovoid mass on the lateral wall of the left ventricle with lower Hounsfield units than myocardium. |
CMR Findings:
CMR was performed on a Philips Achieva 1.5 Tesla scanner using a mass protocol. Imaging revealed a well-circumscribed 7.1 cm x 6.0 cm mass within the lateral wall of the left ventricle (Movie 1), causing significant compression of the LV cavity.
 Movie 1: Hypointense, large intramural mass in the lateral wall of left ventricle. |
The mass was hypointense compared to the myocardium on both T1-weighted (Figure 2) and T2-weighted black blood sequences, with no signal suppression on fat saturation imaging (Figure 3).
 Figure 2: T1 weighted black blood axial image at end diastole with hypointense mass (578.7, indicated by region 1 in the figure) in LV lateral wall as compared to myocardium (622.9, indicated by region 2 in the figure). |
 Figure 3: T2 weighted (a) and T2 with fat saturation (b) with hypointense signals in LV mass as compared to the myocardium respectively. |
On parametric mapping, pre-contrast native T1 and T2 sequences, the mass was homogeneous with low relaxation time (913msec) and low decay time (33msec) respectively. The increased T1 and T2 mapping values are likely due to peri-mass edema (Figure 4).
  Figure 4: a. Native T1 axial image demonstrates a homogenous mass with low relaxation time (913 msec) as compared to myocardium (1020 msec). b. Native T2 axial image demonstrates low decay time (37 msec) as compared to myocardium (53 msec) suggestive of low vascularity within the mass. The myocardium surrounding the mass had elevated T2 decay time likely due to edema. |
First-pass perfusion images demonstrated minimal enhancement, indicating low vascularity (Movie 2).
 Movie 2: First pass perfusion image with minimal contrast uptake within the mass. |
Delayed post Gadolinium imaging revealed marked homogeneous enhancement of the mass, suggesting increased interstitial space within the mass, consistent with high fibrous content (Figure 5). These findings pointed towards a diagnosis of cardiac fibroma, a nonmalignant pathology.
  Figure 5: Delayed post gadolinium enhancement with increased homogenous uptake due to increased interstitial space suggestive of a fibrous composition of the mass. |
Conclusion:
The CMR findings were highly suggestive of a cardiac fibroma. Due to the size of the mass and the patient’s symptoms, she was promptly referred for surgical resection. Pre-bypass transesophageal echocardiography again demonstrated the large homogeneous left ventricular mass (Movie 3).
 Movie 3: 4-chamber transesophageal echocardiogram demonstrating the large cardiac fibroma. |
Despite no known dysrhythmias prior to surgery, the patient did suffer a ventricular fibrillation arrest perioperatively. The excised specimen was a firm, white, well circumscribed mass (Figure 6). Histopathological examination revealed eosinophilic spindle cells with thin, ovoid, compressed nuclei and no evidence of malignancy, confirming the diagnosis of cardiac fibroma. There has been no recurrence of dysrhythmia following tumor resection.
 Figure 6: Gross pathology of excised cardiac mass. |
Post operative transthoracic imaging demonstrated no residual mass and normal left ventricular systolic function (Movie 4).
 Movie 4: Post-operative transthoracic image, 4-chamber view, demonstrating no residual mass and preserved systolic function. |
Perspective:
Cardiac fibroma is a benign tumor primarily composed of fibroblasts, collagen, and connective tissue.[1] While it is the second most common benign primary tumor in children, it is a rare condition in adults, with fibroma representing less than 1% of cardiac masses in adults.[3] Most cardiac fibromas are located in the left ventricular free wall, the interventricular septum (IVS), and the right ventricular outflow tract. Notably, masses in the IVS are associated with higher mortality rates.
Despite their large size, the majority of patients remain asymptomatic. As the cardiac fibroma progresses, symptoms may develop, including chest pain, palpitations, and shortness of breath. However, unlike most benign cardiac tumors, cardiac fibromas carry a significant risk of ventricular arrhythmias and sudden cardiac death.[1] Additionally, due to the expansive nature of cardiac fibromas, valvular obstruction or regurgitation can sometimes occur. Therefore, early diagnosis and resection of cardiac fibromas are crucial for preventing these serious complications.[2]
CMR is the preferred imaging modality due to its superior spatial resolution and tissue characterization.[4] In this case, the cine images revealed a well-circumscribed mass with minimal vascularity on first-pass imaging, suggesting a benign tumor. The hypointense signals observed on both T1-weighted and T2-weighted fat saturation images indicate a homogeneous mass with low fluid and lipid content, respectively. Additionally, the diffuse enhancement seen in delayed gadolinium images further supports the presence of increased fibrous tissue within the mass. Collectively, these findings are consistent with a definitive diagnosis of cardiac fibroma.
This case underscores the importance of utilizing CMR for definitive tissue characterization to establish a clinical diagnosis, thereby reducing the need for additional invasive tests and providing reassurance to the patient if the pathology is benign. The ability to accurately delineate the pathology through imaging allows for timely referral for surgical evaluation, ultimately decreasing hospital stay duration and avoiding unnecessary testing. Therefore, understanding the key features of specific pathologies, such as cardiac fibroma on CMR, is essential for facilitating prompt diagnosis and management without the need for further invasive procedures.
Click here to view the entire study on Cloud CMR
References:
- McAllister HA Jr, Hall RJ, Cooley DA. Tumors of the heart and pericardium. Curr Probl Cardiol. 1999 Feb;24(2):57-116. PMID: 10028128.
- Miyake CY, Del Nido PJ, Alexander ME, Cecchin F, Berul CI, Triedman JK, Geva T, Walsh EP. Cardiac tumors and associated arrhythmias in pediatric patients, with observations on surgical therapy for ventricular tachycardia. J Am Coll Cardiol. 2011 Oct 25;58(18):1903-9. doi: 10.1016/j.jacc.2011.08.005. PMID: 22018302.
- Torimitsu, S., Nemoto, T., Wakayama, M. et al. Literature survey on epidemiology and pathology of cardiac fibroma. Eur J Med Res 17, 5 (2012). https://doi.org/10.1186/2047-783X-17-5
- Finke K, Gietzen T, Steven D, Baldus S, Ten Freyhaus H, Maintz D, Pennig L, Gietzen C. Cardiac fibromas in adult patients: a case series focusing on rhythmology and radiographic features. Eur Heart J Case Rep. 2024 Aug 8;8(8):ytae410. doi: 10.1093/ehjcr/ytae410. PMID: 39171139; PMCID: PMC11337122.
Case Prepared By:
Robert D. Tunks, MD, MHS
Editorial Board, Cases of SCMR
Penn State Health Children’s Hospital
Hershey, PA