Caseous calcification of the mitral annulus (CCMA) is a rare variant of mitral annular calcification, which can be difficult to diagnose and can be misdiagnosed as a cardiac tumour or abscess. Multimodality imaging is important for the diagnosis of this entity and to avoid unnecessary surgical treatment. We present the case of a 77-year-old female patient with initially asymptomatic CCMA who later developed a third degree atrio-ventricular heart block.  Four years after the initial diagnosis, she was admitted to the hospital for acute heart failure due to mitral stenosis. Multimodality imaging including transthoracic, transoesophageal echocardiography and CT scan showed an increase in the CCMA’s size with symptomatic mitral stenosis.