Caseous calcification of the mitral annulus: a rare variant of mitral annular calcification

To the editor: Mitral annular calcification (MAC) is a common echocardiographic image mostly seen in elderly women, found in almost 10% of the population over 50 years old. MAC describes a degenerative process of the mitral annulus, particularly involving the posterior mitral valve annulus. Caseous calcification of the mitral annulus (CCMA) is a rare variant of MAC, constituting 0.6% of all MAC cases.1,2 Herein we present a case of CCMA, which can be misdiagnosed as cyst, abscess or mass. A 76-year-old female patient was admitted to the neurosurgery department for lumbar spondylosis and scoliosis surgery. She was consultated to our clinic for preoperative uncontrolled hypertension. The patient had no complaints except for musculoskeletal problems. She had had a hypertension history for approximately ten years. On physical examination, a 2/6 apical systolic murmur was oscultated and transthoracic echocardiography (TTE) was performed. TTE revealed normal left ventricle systolic functions, left ventricular concentric hypertrophy (interventricular septum 16 mm, posterior wall 14 mm), moderate mitral regurgitation and round mass with smooth borders adjacent to the mitral posterior valve (Figure 1A). Subsequent transoesophageal echocardiography (TEE) demonstrated a round echo-bright mass with a central echo-lucent area and no acoustic shadow (Figure 1 B-D). No further examination was needed because of the typical morphology and the patient’s skeletal disorders. Five days later, the patient was operated with no complication.Figure 1.: Transthoracic (A) and xplane transoesophageal echocardiography views of CCMA (B). 3D figures were obtained from left ventricle and left atrium respectively (C, D). Yellow arrows show CCMA images with different perspectives.CCMA is composed of fatty acids and calcium and cholesterol particles. This finding can be misdiagnosed as cyst, myocardial abscess, tumor or thrombus, and may lead to unnecessary explorative cardiotomy. CCMA is usually a benign lesion and requires no therapuetic intervention. Patients are mostly asymptomatic, but this lesion can rarely cause mitral regurgitation, mitral stenosis, stroke and AV block.3 Surgical approach should be avoided unless there are signs of these complications. Echocardiographers should be aware of this rare image and direct surgeons to avoid unnecessary thoracotomies.