Case report: giant cardiac malignancy in a nine-year-old female.

Purpose: To describe the management of a giant cardiac malignancy initially diagnosed as an anterior mediastinal mass.

Clinical Features: A nine-year-old female with right facial swelling and chronic cough was diagnosed with a large right mediastinal mass. Intermittent ventricular and supraventricular arrhythmias were noted on admission electrocardiograms. Empiric corticosteroid and radiation therapy did not reduce the size of the tumour, and initial tissue biopsies were non-diagnostic. Due to worsening tamponade physiology and persistent arrhythmias, the patient was scheduled for tumour debulking with potential resection. Prior to surgery, a multidisciplinary team was assembled to delineate team member responsibilities and treatment algorithms. The procedure was performed under general anesthesia with spontaneous ventilation preserved during endotracheal intubation and invasive line placement. The team was prepared to provide extracorporeal mechanical support if needed. The child required inotropic and vasoactive medications after transitioning to positive pressure ventilation, but her hemodynamics improved with sternotomy. The lesion was identified as a malignant cardiac clear-cell tumour that was unresectable. Her sternum was left open, as attempted closure led to the re-creation of tamponade physiology. She underwent delayed sternal closure days later. After months of chemotherapy that resulted in significant tumour involution, she underwent successful surgical resection.

Conclusion: Giant primary cardiac tumours may present similarly to large anterior mediastinal masses. The care of patients with these lesions requires an understanding of the risks associated with mediastinal masses as well as those unique to cardiac tumours. A multidisciplinary approach is critical to providing safe and effective care throughout this process.