Figura 1. Axial cardiac computed tomography (A) of right ventricle as seen on the cardiac magnetic r...

Figura 2. Fluoroscopic imaging in the anteroposterior projection showing the bioptome in the RV whil...

Figura 3. Biopsy of right ventricular mass. The histological cuts were analyzed using hematoxylin an...

Introduction

Cardiac neoplasms are rare lesions mostly found in autopsies or during cardiac imaging studies.1 The hamartoma of mature cardiac myocytes (HMCM) is a rare cardiac neoplasm that was first described by Tanimura et al. back in 1988.2 We present the case of a patient diagnosed of HMCM through a transthoracic echocardiography (TTE)-guided-endomyocardial biopsy (EMB).

Clinical case

This is the case of a 32-year-old male patient without cardiovascular risk factors and a past medical history of pulmonary tuberculosis that required complete tuberculostatic treatment. The patient had been showing signs of congestive heart failure [NYAH functional class (FC) I] for 3 months now with progression into FC III. No heart murmurs were found on the physical examination. The ECG showed signs of biatrial dilatation and complete right bundle branch block. The TTE performed revealed the presence of preserved right ventricular (RV) systolic function, moderate tricuspid failure, and mild-moderate pulmonary hypertension. Also, a mass occupying the RV was found, but its thrombotic origin could not be ruled out.

For better characterization purposes, a cardiac computed tomography scan was performed that confirmed a RV hypodense image of a similar density to that of the cardiac muscle both in the arterial and late phases that was consistent with a primary and/or secondary organ process of the right ventricle. Afterwards, the cardiac magnetic resonance imaging performed revealed in the RV—at midventricular level and in close relation with the interventricular septum—the presence of a fixed endocavitary image of a similar intensity to that of the myocardium in the cine, T1, and T2 sequences, and in the fat-suppression sequences (on T1 and T2). The administration of gadolinium triggered the contrast enhancement of all the phases and the possibility of an image compatible with a thrombus was eventually ruled out. A whole-body positron emission tomography was performed to assess the origin of the tumor and eventually rule out the possibility of a secondary origin.

Together with the hospital Interventional Cardiology and Cardiovascular Surgery Unit the heart team decided to perform a TTE-guided EMB due to the patient’s poor general health status to eventually perform heart surgery with tumor resection. The EMB was performed via right anterior transjugular access through an 8-Fr Avanti+ introducer sheath (Cordis, California, United States) with a 50 cm 8-Fr Novatome bioptome (Scholten Surgical Instruments Inc, California, United States). A total of 8 samples were taken, 3 for a TB culture test that ended up testing negative, and 5 for the histopathological analysis that confirmed the presence of cardiac tissue with disorganized and hypertrophic mature cardiomyocytes with cytoplasmic vacuolization, interstitial fibrotic foci, and presence of adipocytes consistent with HMCM.

The patient progression was good with medical therapy, and he was eventually discharged from the hospital. Currently, he is waiting for the surgical resolution of his case.

Discussion

Primary cardiac neoplasms are a rare entity with an incidence rate of 0.001% to 0.3%. Of these, 75% are benign.1 Differentiating the different tumors is challenging. The echocardiography, the cardiac computed tomography scan, and the cardiac magnetic resonance imaging often reveal the location and precise size of cardiac tumors. Still, achieving a definite diagnosis is difficult because the appearance of the image is not pathognomonic.3 Due to the low sensitivity of imaging modalities achieving definitive diagnoses, the tumor microscopic assessment has become the gold standard.1,3

EMB, described by Sakakibara and Konno in 19624 is a safe method with a rate of serious complications < 1%.5,6 Currently, its main indication is for heart transplant rejection monitoring and in patients with early-onset heart failure associated with dilated cardiomyopathy and ventricular arrhythmias.5 According to the different studies published to this date EMB is not very much used to diagnose cardiac masses because it can provide inconclusive tissue samples.3,5 Heart surgery with tumor resection is the treatment of choice because it provides a more detailed histopathological analysis. However, in selected cases, diagnosis can be achieved through an EMB, thus sparing surgery (eg, lymphomas or infiltrative masses where surgical resection may not be feasible).6

The current ACC/AHA/ESC clinical practice guidelines establish that the EMB is a reasonable procedure to diagnose cardiac tumors (Class IIa recommendation) if 4 specific criteria are met: diagnosis cannot be achieved otherwise; the diagnosis achieved through the EMB will change treatment; the EMB success rate is reasonably high; the EMB should be performed by an experienced operator.7

Different reports have described the diagnostic utility of TTE-guided EMB or transesophageal echocardiography (TEE)-guided EMB.8,9 The TEE is the most suitable imaging modality here, although it is also the most invasive of the two. Regarding TTE and TEE-guidance, another option to acquire more information, avoid general sedation, and minimize the radiologist’s exposure to radiation is to use intracardiac echocardiography (ICE). It is a new imaging modality based on the use of a diagnostic ultrasound catheter.10 Although it is a useful new imaging modality in this type of cases, the ICE is limited by its high cost associated with single-use catheters.

Conclusion

Cardiac tumors are rare entities. The TTE, TEE or ICE-guided EMB is a safe and reliable procedure to achieve a definitive diagnosis of cardiac tumor. However, surgical resection followed by microscopic assessment is still the gold standard.

1. Mantilla-Hernández JC, Amaya-Mujica J, Alvarez-Ojeda OM. An Unusual Tumour: Hamartoma of Mature Cardiac Myocytes. Rev Esp Patol Jan-Mar 2019;52(1):50-3.

2. Tanimura A, Kato M, Morimatsu M. Cardiac hamartoma. A case report. Acta Pathol Jpn 1988;38:1481-4.

3. Strecker T, Rösch J, Weyand M, Agaimy A. Primary and metastatic cardiac tumors: imaging characteristics, surgical treatment, and histopathological spectrum: a 10-year experience at a German heart center. Cardiovasc Pathol. 2012;21:436-43.

4. Sakakibara S, Konno S. Endomyocardial biopsy. Jpn Heart J 1962 Nov;3:537-43.

5. Isogai T, Yasunaga H, Matsui H, Ueda T, Tanaka H, Horiguchi H, Fushimi K. Hospital volume and cardiac complications of endomyocardial biopsy: a retrospective cohort study of 9508 adult patients using a nation wide in patient database in Japan. Clin Cardiol 2015 Mar;38(3):164-70.

6. Francis R, Lewis C. Myocardial biopsy: techniques and indications. Heart 2018;104:950-8.

7. Cooper LT, Baughman KL, Feldman AM, et al. The role of endomyocardial biopsy in the management of cardiovascular disease: a scientific statement from the American Heart Association, the American College of Cardiology, and the European Society of Cardiology Endorsed by the Heart Failure Society of America and the Heart Failure Association of the European Society of Cardiology. Eur Heart J 2007;28:3076-93.

8. Oka T, Masaoka Y, Hironori Ueda H, Shiode N, Hayashi Y, Kihara Y. Primary cardiac lymphoma diagnosed by endomyocardial biopsy using transthoracic echocardiography in the substernal window. J Med Ultrasonics 2013;40:483-5.

9. Scholte A, Jos Frissen PH, van der Wouw P. Transesophageal echocardiography-guided transvenous biopsy of an intracardiac tumor. Echocardiography 2004;21(8):721-3.

10. Takashima A, Ogata T, Yamada H, Tetsuzo Wakatsuki T, Sata M. Intracardiac Echocardiography-Guided Biopsy of a Lipomatous Cardiac Tumor Arising From the Interatrial Septum. Circ J 2017;81:1553-5.

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