Right Atrial Non-Valvular Papillary Fibroelastoma Causing Paradoxical Embolic Stroke Through an Ostium Secundum Atrial Septal Defect: A Case Report

Papillary fibroelastoma (PFE) is a rare benign cardiac tumor, usually left-sided and valvular. Right-sided, non-valvular PFEs are uncommon, and systemic embolization from these lesions is particularly rare, typically requiring an interatrial shunt. We report a surgically confirmed right-atrial, non-valvular PFE presenting with paradoxical embolic stroke through an ostium secundum atrial septal defect (ASD). A 72-year-old woman with recurrent ischemic cerebrovascular events was admitted with an acute posterior circulation stroke. Transthoracic echocardiography was nondiagnostic. Transesophageal echocardiography revealed a 13 x 14 mm highly mobile mass attached to the free wall of the right atrium and an ostium secundum ASD (about 9-10 mm) with bidirectional shunting. Surgical resection of the mass with concomitant ASD closure was performed 14 days after the index stroke. Gross inspection suggested a frond-like tumor; histopathology confirmed PFE. Postoperative recovery was uneventful. Anticoagulation was resumed for a new distal deep-vein thrombosis, and no further embolic events have occurred during follow-up. This case illustrates an unusual mechanism of systemic embolism from a right-sided, non-valvular PFE via paradoxical embolization through an ASD. It emphasizes the limitations of transthoracic echocardiography in detecting small or atypically located PFEs and supports transesophageal echocardiography as the modality of choice when clinical suspicion persists. In symptomatic patients or after embolism, surgical excision, particularly with simultaneous closure of right-to-left shunts, should be considered to minimize recurrence risk. Clinicians should include PFE in the differential diagnosis of recurrent cryptogenic stroke and actively search for interatrial shunts when right-sided tumors are suspected.