Caseous Necrosis of the Mitral Annulus Mimicking a Cardiac Mass: A Rare Presentation.

Caseous mitral annular calcification (CMAC), a rare variant of mitral annular calcification (MAC), predominantly affects older adults. CMAC represents a very small fraction of MAC, and it features a necrotic core with peripheral calcifications, mimicking neoplasms. Multimodal imaging is essential for diagnosis. We present a case of an 86-year-old hypertensive male patient who presented with exertional dyspnea. Transthoracic echocardiography revealed severe left ventricular hypertrophy, a left cardiac mass, and severe MAC. Cardiac MRI confirmed CMAC (12×14 mm calcified mass). He was managed medically and surveilled with serial echocardiograms. While asymptomatic cases may regress, complications (emboli, valve dysfunction) warrant surgery. Advanced imaging prevents misdiagnosis, guiding intervention. CMAC necessitates multimodal imaging for accurate diagnosis. Conservative management with serial monitoring is appropriate in asymptomatic patients, underscoring the importance of clinician awareness to mitigate complications. Early recognition ensures optimal outcomes in these rarer etiologies.