Primary tumors of the heart are infrequent with an overall incidence of 0.02% based on autopsy series [1]. With the routine use of noninvasive imaging, cardiac tumors are often found incidentally. However, a left ventricular (LV) mid-cavitary mass is rarely seen and can challenge a clinicians’ diagnostic ability. The diagnosis relies on multimodality cardiovascular imaging, including echocardiography, cardiac computed tomography (CCT), and cardiovascular magnetic resonance (CMR). The etiology of a LV mass can be determined by its location, attachment, mobility, enhancement, and vascularity.

In the setting of an acute myocardial infarction (AMI), a LV mass is likely to represent a thrombus. Approximately 7% of patients with an anterior AMI develop a LV thrombus [2, 3], which is considerably more prevalent than primary cardiac tumors. Nonetheless, it is important to have a broad differential when approaching a LV cavitary mass, including thrombus, tumors, both benign and malignant, or rarely a vegetation.

We describe a case of a 43-year-old female post AMI diagnosed with a mid-cavitary mass within the LV. Despite the use of multimodality cardiovascular imaging, she required surgical excision for the rare diagnosis of a papillary fibroelastoma.

Cardiac papillary fibroelastomas (PFE’s) are uncommon, benign, avascular cardiac tumors. With an estimated frequency as high as 0.33% on autopsy series, PFEs constitute up to 7% of all primary cardiac tumors [4]. PFEs are typically found on the valvular surface of the heart, most commonly involving the aortic and mitral valves [5]. Non-valvular PFEs are exceedingly rare, with only 55 patients identified in a systematic search of the literature using the MEDLINE database [6]. Although the pathophysiology of PFE is not entirely understood, there is a strong association with previous open-heart surgeries and thoracic radiation [7]. Damage to the endothelium, trauma, and organizing emboli have been suggested mechanisms [8]. Although it is a benign tumor, PFE’s can present with ischemia or severe embolic sequelae, especially when the mass arises in the left side of the heart [9]. Surgical removal of PFE can reduce the risk of embolization.

Echocardiography is the most readily and cost effective imaging modality available to assess a LV mass. It provides basic information on mass morphology, mobility, position, and attachment. Contrast echocardiography using Definity allows additional classification based on vascularity [7]. Despite its superior temporal resolution, ease of portability and real-time imaging, complete definition of cardiac masses may not be possible with echocardiography alone. Both CT and CMR allow high contrast resolution and evaluation of myocardial infiltration. CT has the benefit of delineating calcification of the mass, while CMR has the added benefits of the contrast agent gadolinium. Late gadolinium enhancement can be used to distinguish thrombi from tumor based on its lack of enhancement. It is also used to identify the presence, location and extent of an AMI [10]. Appropriate use of these various non-invasive cardiac imaging modalities often allows differentiation of the mass and a pre-operative diagnosis.

Our case presents a unique challenge to pre-operative diagnosis. Although echocardiography and CMR suggested that the mass was a thrombus, given the context of the recent anterior MI, exploration and surgical excision was completed by the surgeon due to the potential for the mass to embolize. The final diagnosis of a PFE was unique due to its unusual location and large size within the LV cavity. This unique case demonstrates shortcomings of multimodality cardiac imaging in the diagnosis of an atypical mass and the importance of obtaining tissue when clinically safe and feasible.