Right Atrial Mass in an Adolescent With a Complex Hematologic History: What Is the Diagnosis?

A 17-year-old female patient with hemoglobin SS sickle cell disease, Moyamoya disease, a history of stroke, and pulmonary embolism was incidentally found to have a large pedunculated right atrial mass on cardiac magnetic resonance imaging. The differential diagnosis included thrombus, tumor, and vegetation. She underwent cardiac catheterization for therapeutic removal and pathologic confirmation of the diagnosis. This case highlights the diagnostic challenges of right atrial masses and the importance of integrating clinical context with multimodality imaging.