The importance of integrated imaging in the difficult differential diagnosis of a left intracardiac mass in young adult

Abstract The patient is a 34–year–old man who comes to the emergency room with mild hemoptysis, asthenia, low–grade fever, night sweats and weight loss. Cardiac auscultation reveals a diastolic murmur at the cardiac apex. Transthoracic and transesophageal echocardiograms are performed and show an isoechoic thickening encompassing the posterior leaflet, cranially involving the atrial septum and the lateral wall up to the inlet of the left atrial appendage and inferiorly involveing the subvalvular apparatus with diffuse thickening and chordal fusion. Functionally it determines a moderate mitral stenosis with an average gradient of 10 mmHg and a valve area of ​​1.1 cm2 and a mild–moderate regurgitation with an anteriorly directed eccentric jet. At this point we needed to make the differential diagnosis considering as possible etiologies infective endocardic vegetation, thrombosis, primary and secondary neoplasms, aseptic vegetation and inflammatory or rheumatic valvulitis. We therefore begin our diagnostic work–up by performing a scintigraphy with labeled leukocytes, which does not show the presence of hyperuptake areas referable to infective endocarditis, and a PET scan which shows, in addition to the increased uptake at the cardiac level, an area of ​​greater concentration of the metabolic tracer in the gastric area (between the body and the fundus). Given the confirmation of metabolically active tissue, the patient performed cardiac magnetic resonance with contrast medium which confirmed the presence of pathological tissue with inhomogeneous late post–contrast enhancement. After collegial discussion, due to the high risk of biopsy of the mitral lesion, which was poorly separable from the cardiac structures, given the other localization of the disease at the gastric level, it was decided to perform an EGDS with relief of an ulcerated lesion on the gastric fundus which is subjected to biopsy and histological typing. We then arrive at the diagnosis of “undifferentiated pleomorphic sarcoma”. Sarcoma is the most frequent histological type of primary malignant cardiac tumors. The clinic is characterized by constitutional symptoms, obstruction of the valve inflow or outflow tract, thromboembolism, and arrhythmias. It has a poor prognosis: 6–12 months from diagnosis. In conclusion, we reiterate the importance of integrated imaging to arrive at the final diagnosis, each method with a specific objective.