Caseous calcification of the mitral annulus: A neglected, unrecognized diagnosis

Background: Mitral annular calcification is a common echocardiographic find ing. Caseous calcification is a rare variant seen as a large mass with echo lucencies that resembles a tumor, occasionally resulting in exploratory car diotomy. The aim of this study was to assess the prevalence of caseous calc ification of the mitral annulus, to evaluate patient characteristics and th e echocardiographic variables for diagnosing this entity, and to describe t he clinical outcome on followup of such patients. Methods. Caseous calcification was defined as a large, round, echo-dense ma ss with smooth borders situated in the periannular region, with no acoustic shadowing artifacts and containing central areas of echolucencies resembli ng liquefaction. Eighteen patients were diagnosed by 2-dimensional echocard iography as having caseous calcification of the mitral annulus. one had cal cification of the tricuspid annulus. Nine patients underwent transesophagea l echocardiographic studies. Results. A typical finding of a round, sometimes semilunar, large, echo-den se, soft mass with central echolucencies seen on both transthoracic and in particular transesophageal echocardiography, resembling a periannular mass, was demonstrated. The mass was posteriorly located in all mitral patients. Transesophageal echocardiography added limited information. Three patients underwent mitral valve replacement. The operative findings were a solid ma ss adherent to the posterior portion of the mitral valve. Sectioning reveal ed a toothpaste-like, white, caseous material. Sixteen (84%) patients were treated conservatively. On follow-up of 3.8 +/- 2.4 years, 4 patients died of unrelated causes. Conclusion: The characteristic appearance of a large, soft, echo-dense mass containing central areas of echolucencies resembling liquefaction at the p osterior periannular region of the mitral valve on 2D echocardiography is c ompatible with the diagnosis of caseous abscess. Such a finding should not be confused with a tumor. Transesophageal echocardiography does not appear to contribute to the diagnosis. This rather impressive lesion appears to ca rry a benign prognosis.