Right Atrial Myxoma in a Young Patient with a DSG-2 Genetic Mutation: A Case Report.

Introduction: Primary heart tumours, particularly right atrial myxomas, are exceedingly rare. We present a particularly unique case of a young patient who was found to have a right atrial myxoma while carrying a desmoglein-2 (DSG-2) gene splice-site variant, a mutation typically associated with cardiomyopathies but not previously reported concomitantly with atrial myxoma development. Case Presentation: A young male in his twenties presented with constitutional symptoms, including dizziness and palpitations. An echocardiogram showed a 3.5-4 cm right atrial mass originating from the right atrium-superior vena cava junction. Surgical excision via midline sternotomy and right atriotomy was performed without complications. Histopathology confirmed a benign atrial myxoma. Given the patient's age and some clinical features suggestive of Carney complex (CNC), genetic testing was undertaken. CNC associated mutations were excluded, but a DSG-2 splice-site variant was identified. This gene is known to play a role in desmosomal integrity and has been implicated in arrhythmogenic right ventricular cardiomyopathy, hypertrophic cardiomyopathy, and dilated cardiomyopathy. However, it has not been previously associated with myxoma pathogenesis. Conclusion: This is the first documented case of a right atrial myxoma concomitantly existing with a DSG-2 variant. While the presence of this gene cannot be directly linked to the presence of a myxoma, the possibility of a genetic association is relevant. Further research and broader genetic screening in such cases can possibly uncover a potential link and aid in the further understanding of atypical cardiac tumour biology.