Tricuspid Stenosis Due to Cardiac Sarcoma.

Primary cardiac sarcomas are rare, aggressive malignant tumors with high recurrence rates and poor prognosis. Their initial presentation is often vague, contributing to diagnostic delay and rapid clinical deterioration. We report the case of a 32-year-old man who presented with gastrointestinal symptoms and constitutional features, initially suggesting a hepatobiliary or infectious cause. As his condition progressed, signs of right-sided heart failure emerged, prompting transthoracic echocardiography, which revealed a large right atrial mass causing tricuspid inflow obstruction and a significant pericardial effusion. Surgical resection confirmed biphasic synovial sarcoma, a subtype previously described in small case series. Despite an initially uncomplicated postoperative course, he subsequently developed atrial flutter with associated left ventricular dysfunction, necessitating cardioversion. Anthracycline toxicity remains a possible contributing factor. This case underscores the importance of maintaining a broad differential diagnosis in young patients with unexplained systemic symptoms and highlights the diagnostic value of early echocardiographic assessment when right-sided cardiac involvement is suspected. It also reinforces the need for multidisciplinary management given the tumor's aggressive behavior and potential for rapid clinical decline.