An immunosuppressed 37-year-old woman with right atrial necrotising myocarditis.

A 37-year-old immunocompromised woman was admitted with palpitations, fevers and myalgias. An echocardiogram demonstrated a mass in the right atrial walls and interatrial septum. Endovascular biopsy of the myocardium revealed neutrophilic necrotising myocarditis isolated to the right atrium. Multiple blood, urine and stool cultures were negative but a high anti-streptolysin O antibody titre was detected. The combination of these findings led to the working diagnosis of necrotising myocarditis. Without a positive culture, it was not possible to definitively state the cause of this condition. She was treated with intravenous antibiotics and continued to improve physically and biochemically on discharge.