can be a rare predisposing factor for infective endocarditis (IE). The surgical treatment strategy for such cases remains uncertain. Case presentation: Methicillin-resistant Staphylococcus aureus (MRSA) IE complicated with purulent pericarditis and ventricular septal abscess was diagnosed in an 81-year-old woman with no significant past medical history. The patient underwent surgical treatment in two stages. The first operation consisted of purulent effusion drainage and pedicled omental flap implantation. The second operation, involving mitral vegetation and ventricular septal abscess debridement, was performed 7 days after the first operation. During the admission, appropriate antibiotic therapy was continued. Within a week after the last surgery, patient status (inflammatory markers, fever, and respiratory function) improved remarkably. However, the IE recurred and the patient finally died of sepsis and acute heart failure due to severe mitral regurgitation on postoperative day 37. This report describes a rare case of IE on MAC due to MRSA, complicated with purulent pericarditis caused by extracardiac invasion. Conclusions: Depending on clinical state of the patients, if annular invasion is suspected and MAC is detected in patients with IE, aggressive debridement and reconstruction of mitral annulus and septum might be necessary for such cases.