A Rare Case of Inflammatory Cardiac Mass in the Young: Diagnostic Uncertainty and Therapeutic Challenges.

Inflammatory cardiac masses are rare and often mimic neoplastic or thrombotic lesions, posing significant diagnostic challenges. These masses are typically identified incidentally during imaging studies, such as echocardiography, and further evaluation with cardiac magnetic resonance imaging (MRI) is required for accurate tissue characterization. Early recognition and appropriate management are crucial to prevent complications. We present the case of a 20-year-old previously healthy female who presented with episodic palpitations lasting seconds to minutes over a two-month period. Transthoracic echocardiography revealed a hyperechoic mass attached to the tricuspid valve, and cardiac MRI indicated inflammatory involvement of the myocardium, with myocardial edema and hyper-trabeculation. Laboratory investigations ruled out infectious etiologies, and she was started on corticosteroid therapy (prednisolone 30 mg daily, tapered over four weeks) along with metoprolol. Despite a reduction in symptoms with treatment, follow-up echocardiography showed persistence of the cardiac mass, raising questions about the efficacy of corticosteroid therapy. During this period, the patient also experienced an episode of ventricular premature contractions (VPCs), detected through smartwatch tracing, although these were not detected on a 24-hour Holter monitor. No significant mass reduction was observed, and her condition remained stable on beta-blocker therapy. This case highlights the diagnostic and therapeutic complexities of inflammatory cardiac masses in young patients. The persistence of the mass despite corticosteroid treatment suggests the potential need for alternative interventions, such as surgical evaluation or biopsy, to confirm the etiology and guide further management. Inflammatory cardiac masses can closely mimic neoplastic growths, necessitating a multidisciplinary approach to optimize outcomes and prevent misdiagnosis. Early detection, accurate diagnosis through advanced imaging, and close follow-up are essential to guide appropriate treatment and prevent complications.