Rapid progression of mitral stenosis during watchful waiting for the asymptomatic degenerative severe aortic stenosis: a case of caseous calcification of mitral annulus

Excerpt

An 80-year old woman was referred to our hospital for an ejection systolic murmur. Transthoracic echocardiography (TTE) revealed severe degenerative aortic stenosis (AS) with wider posterior mitral annulus calcification (MAC). Both the anterior mitral leaflet (AML) and posterior mitral leaflet (PML) appeared to have thickened by calcification without echolucencies, resulting in moderate mitral stenosis (MS) (Fig. 1a). Surgical intervention for severe AS was considered, and watchful waiting for a year was planned because she had no obvious symptoms indicative of AS. However, she returned to our hospital 9 months later because of worsening exertional dyspnea. The severity of AS was unchanged on TTE, but a round calcified mass with a central echolucent area without acoustic shadowing was found to be attached to the middle of the AML continuously from the MAC (Fig. 1b). Three-dimensional transesophageal echocardiography (3D TEE) illustrated the extensive calcification of the medial AML and PML, which bulged into the left atrium side, and the highly limited mobility of the medial mitral valve, including the posterior commissure with 0.9 cm² of mitral valve area, suggesting severe MS (Fig. 1c). Double valve replacement with mechanical valves was performed, a soft, fragile mitral tumor was confirmed, and white toothpaste-like milky materials were intraoperatively drained (Fig. 1d). Upon Histopathological analysis with hematoxylin and eosin staining, the resected mass showed nodular calcification with basophilic amorphous material (Fig. 1e), consistent with caseous calcification of the mitral annulus (CCMA).

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