Leiomyosarcoma as an incidental finding in a patient in the fifth decade of life with a history of precordial pain and dyspnea. (QF_TH_040)

Description of Clinical Presentation: In March 2024, the patient began to experience a deterioration in functional class, characterized by dyspnea with moderate to minor efforts, associated with productive cough. An internist referred the patient to a cardiologist for specialized care, where they found Pro-BNP levels at 3157 pg/ml; an echocardiogram was performed, in which they reported a dilated left atrium with a tumor lesion inside.

Diagnostic Techniques and Their Most Important Findings: In order to better assess the spatial and tissue characteristics of the lesion, thoracic computed tomography and cardiac magnetic resonance were performed. The data obtained led to the decision to perform surgical removal of the mass. At the end of this procedure, the tissue was sent to the pathology department where a sarcomatous lesion compatible with leiomyosarcoma was diagnosed.

Learning Points from this Case: Thoracic CT scan: a solid and heterogeneous tumor was observed inside the left atrium. Its estimated measurements were 82 x 41 x 48 mm. It extends towards the ostium of the right veins in its posterior portion, contacts the mitral valve in its anterior portion, the left atrial appendage in its upper portion and the floor of the left atrium in its lower portion, towards the medial aspect it displaces the interatrial septum to the right. After the administration of intravenous iodinated contrast, it presents heterogeneous enhancement most likely secondary to the presence of areas of internal necrosis.
Cardiac magnetic resonance imaging: Due to the greater sensitivity of this imaging method to identify tissue interfaces, it is demonstrated that the tumor already described shows adherence, but not invasion, towards the interatrial septum; on the other hand, in steady state free precession (SSFP) sequences, displacement of the interatrial septum to the right is seen, causing acceleration of the flow of both vena cava and the left ventricular outflow tract and limiting the closure of the anterior leaflet of the mitral valve.