An intracavitary right ventricular mass: a diagnostic dilemma-a case report.

Background: Intracardiac masses are a diagnostic challenge in cardiology because thrombus and malignancy may demonstrate similar imaging features on initial evaluation. Case summary: An elderly male admitted for sepsis was incidentally found to have a right ventricular outflow tract mass initially presumed to be thrombus, and anticoagulation was initiated. Follow-up imaging demonstrated interval enlargement despite therapy, prompting further evaluation. Transesophageal echocardiography and cardiac magnetic resonance raised concern for malignancy, and biopsy confirmed poorly differentiated non-small cell lung carcinoma with cardiac metastasis. Given advanced disease and poor functional status, disease-directed therapy was deferred, and hospice care was pursued. Discussion: Cardiac metastases are more common than primary cardiac tumours and occur in up to 9%-14% of patients with metastatic cancer, with lung cancer representing the most frequent primary source. Prior literature emphasizes multimodal imaging when presumed thrombus fails to respond to anticoagulation. Conclusion: Interval growth of an intracardiac mass despite anticoagulation should prompt diagnostic reassessment and advanced cardiac imaging.