IntroductionGranulomatosis with polyangiitis (GPA) is a chronic condition characterized by granulomatous inflammation of blood vessels, leading to damage in various organs, including the lungs, kidneys, and sinuses. This pattern of involvement can complicate the diagnosis of coexisting conditions, especially those involving granulomatous inflammation, like tuberculosis (TB). Its treatment typically involves the use of immunosuppressants, which can further complicate the diagnosis of infectious conditions. (1) Cardiac tuberculosis (TB) is a rare but clinically significant extrapulmonary manifestation of tuberculosis, often presenting substantial diagnostic challenges due to its nonspecific symptoms. Timely diagnosis and management are crucial as TB’s involvement in cardiac tissues can result in severe complications such as tuberculous pericarditis and cardiac tamponade. (2) Patients may exhibit symptoms like fatigue, weight loss, dyspnea, and chest pain, which can easily mimic other cardiac conditions, complicating both diagnosis and management. The prevalence of cardiac TB varies geographically, with notably higher rates observed in regions where TB is endemic. (2) In addition to cardiac TB, mitral-aortic intervalvular abscesses represent another rare yet critical complication associated with infective endocarditis, particularly in patients with pre-existing cardiovascular disease. This anatomical region, known as the mitral-aortic intervalvular fibrosa (MAIVF), consists of fibrous and avascular tissue that is particularly vulnerable to infections and trauma. These abscesses occur in less than 1% of endocarditis cases and can lead to severe sequelae, such as valvular dysfunction and heart failure, if not diagnosed and treated promptly. (3, 4)The primary causative agents are often bacterial infections, particularly from organisms like Staphylococcus aureus. These infections can invade the fibrous tissue following surgical interventions or arise in the context of chronic conditions that predispose patients to endocarditis.(5, 6) The co-occurrence of tuberculosis (TB) and granulomatosis with polyangiitis (GPA) presents a significant clinical challenge, especially among immunocompromised patients. This case report details a 45-year-old woman with end-stage renal disease secondary to GPA who developed an MAIVF abscess with necrotizing granulomatosis inflammation and a positive tissue PCR for TB. Understanding the interplay between these two conditions is critical for guiding distinct therapeutic approaches, given that both involve granulomatous inflammation.