Sarcoidosis presenting as a large intracardiac mass: a case report.

Background: Sarcoidosis is a systemic granulomatous disease that occasionally affects the heart and poses the risks of arrhythmias, heart failure, and sudden cardiac death.

Case summary: We report a rare case of cardiac sarcoidosis presenting as a large intracardiac mass in a 76-year-old woman that was incidentally detected during a health check-up. Transthoracic echocardiography revealed a 25× 33 mm mobile mass in the left atrium. Cardiac magnetic resonance and ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography demonstrated heterogeneous enhancement and increased metabolic activity, respectively, raising the suspicion of cardiac sarcoidosis. Bronchoscopic biopsy confirmed the presence of epithelioid granulomas, supporting the diagnosis. Surgical resection was performed because of the size of the mass and the potential for mitral valve obstruction. Histopathology confirmed the presence of non-caseating granulomas consistent with sarcoidosis. Postoperatively, corticosteroid therapy with prednisolone (initially 30 mg/day, tapered to 5 mg/day) was initiated to treat the residual lesions identified on imaging. The residual mass showed regression, with resolution of inflammatory activity, through the use of steroid therapy during follow-up.

Discussion: This case report highlights the diagnostic and therapeutic challenges associated with cardiac sarcoidosis presenting as a large intracardiac mass. Our findings underscore the importance of a multidisciplinary approach that utilises advanced imaging techniques, histological confirmation, and tailored management strategies that combine surgical intervention and immunosuppressive therapy for diagnosis and treatment.