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Caseous Calcification of the Mitral Annulus

Published Online:https://doi.org/10.1148/radiol.231322

A 52-year-old man presented to the hospital with dyspnea on exertion for 3 months. He had a history of connective tissue disease and pulmonary interstitial fibrosis. Chest radiography showed a calcified rounded nodule projected over the mitral annulus region (Figure, A). Transthoracic echocardiography showed a 2.2 × 2.0-cm mass at the base of the mitral annulus that had smooth borders and an echolucent center (Figure, B). Cardiac CT angiography showed the characteristic findings of caseous calcification of the mitral annulus (CCMA) with a central isodense area and a peripheral calcified region (Figure, C). Follow-up echocardiography at 1 year showed no significant changes of the mass or of mitral valve function.

(A) Chest radiograph shows a round calcified nodule projected over the mitral                 valve annulus. (B) Four-chamber view from transthoracic echocardiography shows a                 mitral valve annulus mass with smooth borders and an echolucent center (arrow). (C)                 Cardiac CT angiogram demonstrates the typical CT appearance of caseous mitral valve                 annular calcification (arrow), with a central region that has lower attenuation than                 the calcified shell.

(A) Chest radiograph shows a round calcified nodule projected over the mitral valve annulus. (B) Four-chamber view from transthoracic echocardiography shows a mitral valve annulus mass with smooth borders and an echolucent center (arrow). (C) Cardiac CT angiogram demonstrates the typical CT appearance of caseous mitral valve annular calcification (arrow), with a central region that has lower attenuation than the calcified shell.

CCMA is a variant of mitral annulus calcification and is usually located in the posterior region of the mitral annulus at the atrioventricular groove (1,2). The prevalence of CCMA is reported to be 0.5%–1% of all mitral annulus calcifications and can be found in 0.06%–0.07% of the total population (3). Due to its unusual characteristics, a tumor may be suspected, and the distinction should be based on the location and classic imaging features. At echocardiography, CCMA is characterized by well-defined borders, internal echolucent areas, and acoustic shadowing. At multidetector CT, this entity manifests as a round (or semilunar) sharply marginated mass, with a hypo- or hyperattenuating center and a calcified peripheral rim. Pathologic examination is rarely required for diagnosis. The differential diagnosis of CCMA includes the following: cardiac tumors, vegetation of subacute bacterial endocarditis, calcified thrombus, and myxoma.

Disclosures of conflicts of interest: X.J.X. No relevant relationships. F.X.Y. No relevant relationships.

References

  • 1. Ghazawi FM, Vinco G, Walker M. Caseous calcification of the mitral annulus: a rare entity confirmed by cardiovascular magnetic resonance imaging. Int J Cardiovasc Imaging 2018;34(1):25–26. Crossref, MedlineGoogle Scholar
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Article History

Received: May 23 2023
Revision requested: June 5 2023
Revision received: June 8 2023
Accepted: June 20 2023
Published online: Oct 03 2023