Tuberculosis (TB) arthritis remains a diagnostic challenge. In addition to clinical presentation, the use of imaging techniques and confirmation of Mycobacterium tuberculosis are essential. We present the case of a 69-year-old female in whom the diagnosis of knee TB arthritis was simultaneously established with the diagnosis of MALT lymphoma. This case report aims to highlight the role of multimodal ultrasound (US) in both diagnosis and its utility in interventional procedures, such as aspiration and synovial biopsy.