Differential diagnosis of cardiac masses by operation view

Key points

• Most patients with cardiac masses are asymptomatic; however, they may present with symptomatology and clinical signs suggestive of more common and rapidly debilitating syndromes such as angina, myocardial infarct, or cerebrovascular insufficiency. Therefore the presence of an intramural or intracavitary mass is usually detected on imaging undertaken to rule out other structural pathologies, such as valvular disease.

• A sequential approach to imaging that allows appropriate use of resources in a step-up fashion is usually undertaken, i.e., bedside modalities (such as transthoracic echocardiography) should be performed prior to more invasive and costly options such as transesophageal echocardiography or cardiac magnetic resonance imaging, as this may satisfactorily rule out the presence of such a mass.

• Each subsequent imaging modality provides useful information, which guides the decision on whether to excise the mass in question. Finally, biopsy or postexcision histopathological analysis may reveal the final diagnosis and tissue characterization.

Box 21.1: Introduction

Cardiac masses represent a rare and complex entity that often result from metastatic cancers or more complicated disease processes. The diagnostic process often involves multidisciplinary approaches with careful multimodal imaging consultations. Cardiac masses can be broadly categorized into tumors, thrombi, vegetations, calcific lesions, and other rare conditions. Unlike other anatomical sites in the body, cardiac masses can have significant repercussions on blood flow obstructions, formation of emboli, and can result in electrical or mechanical dysfunction as a result of interference with the underlying anatomy. Presentations of such masses need to be viewed with a full diagnostic workup which involves clinical presentation imaging, invasive and noninvasive investigations, and long-term management considerations. These masses can be further divided into subcategories including benign and malignant primary and nonneoplastic tumors, or by the anatomical site that they occupy such as intracardial or pericardial tumors which fall under the category of cardiac masses .

The process of reaching a diagnosis surrounding a space occupying lesion or mass in the heart can be done as a result of symptomology or specific incidents. The majority of tumors found in the heart tend to be benign with over a 50% being a myxoma. Primary malignant tumors are very rare accounting for less than 25% of primary cardiac tumors, and in the majority of cases these would present as sarcomas. In studies performed on autopsy results, cardiac tumors are most commonly present as metastatic malignant tumors. The prevalence of first-degree cardiac tumors is 1 in 2000 whereas autopsies and autopsy studies show a ratio of 1 in 100 for metastatic tumors. This indicates a ratio of primary to secondary cardiac tumors in the range of 20 to 1. However, there is great variation among autopsy studies with ranges of the incidence of cardiac metastases from 2.3% to 18.3% in patients with extracardiac malignant tumors .

Multimodal cardiac imaging including transthoracic echocardiography, transesophageal echocardiography, cardiac magnetic resonance, cardiac computed tomography, and fluorodeoxypositron emission tomography have a complementary and reinforcing role in the evaluation of cardiac masses. Given the diverse range of cardiac masses that can be identified both on autopsy imaging and other forms of investigation, there are currently no strict guidelines or general consensus on the diagnostic algorithm or best diagnostic approach in identifying these masses .

This chapter aims to outline a classification-based approach to identifying and diagnosing each type of cardiac mass.