Cardiac Papillary Fibroelastoma: Atypical Presentation Mimicking Infective Endocarditis With False Positive Commensal Blood Cultures

Abstract

Cardiac papillary fibroelastomas (CPFs) are rare benign cardiac neoplasms that carry a high risk of embolization if not diagnosed and managed in a timely manner. As most patients are asymptomatic, CPF may be incidentally detected on transthoracic echocardiography (TTE) when performed for other indications. Management of incidental CPF in asymptomatic patients is debatable. We report an unusual case of an incidental CPF in an asymptomatic patient admitted to the hospital for presumed infective endocarditis (IE). Two weeks following laser resection of laryngeal cancer (LC), a new pansystolic murmur was audible during a routine cardiology visit. Outpatient TTE revealed a "vegetation-like" lesion on the mitral valve (MV). Blood cultures (BC) with Gram-positive cocci in clusters (GPC) were reported within 24 hours. This prompted hospital admission for empiric antibiotics. A transesophageal echocardiogram (TEE) confirmed the lesion to be an echogenic mass attached to the MV consistent with CPF. Repeat BC, prior to empiric antibiotic initiation, were all negative. In the absence of all other signs and symptoms of IE, it was determined that the initial BC was false positive and IE was ruled out. Surgical resection was performed due to the potential risk of embolization. The pathology confirmed the diagnosis of CPF with negative tissue cultures.

Keywords: benign cardiac tumor; cardiac papillary fibroelastoma; cardiac tumors; case reports; infective endocarditis; primary cardiac tumors; valvular lesions.

Figure 1. Transesophageal echocardiogram showing a 1.2×1.4 cm echogenic mass attached to the atrial side of the posterior mitral leaflet (white arrows).

(A and B) Apical view during systole and diastole, respectively. (C and D) Three-dimensional view during systole and diastole, respectively. Note mass moving into the left ventricle during diastole (B and D). LA: left atrium; LV: left ventricle; LVOT: left ventricular outflow tract; RV: right ventricle

Figure 2. Histological examination of the intracardiac mass during and post-open-heart surgery.

The images show (A) mass attached between P2 and P3 indentation of the posterior MV leaflet (black arrow), (B) MV appearance post-surgical resection with complete preservation of the posterior leaflet (white arrow), (C) 1×1×0.6 cm of tan-white entirely papillary fragment of soft tissue mass, (D) hematoxylin and eosin staining showing avascular papillary tissue with a surrounding layer of endothelium. MV: mitral valve; A1: anterior leaflet segment; A2: middle leaflet segment; A3: posterior leaflet segment; P1: anterior or medial leaflet scallop; P2: middle leaflet scallop; P3: posterior or lateral leaflet scallop