Myxomatous Degeneration
of the Mitral Valve
Mitral Valve Prolapse
Epidemiology and Etiology:
Common sites:
Gross features:
- one or more
leaflets are “floppy”
- intercordal ballooning (hooding) of the mitral leaflets or portions thereof
- enlarged,
redundant, thick, rubbery leaflet(s)
- tendinous cords elongated, thinned, and
occasionally ruptured
- annular dilation
(rare in other causes of MV insufficiency)
- tricuspid valve concomitantly involved
(20-40%)
- aortic or pulmonic valves may also be affected
- absence of
commissural fusion
- fibrous thickening
where leaflets rub together
- linear fibrous
thickening of the left ventricular endocardial
surface where cords snap against it
- thickening of the
mural endocardium of the left ventricle or
atrium where prolapsing leaflets strike
- thrombi at atrial surface of leaflets in recesses behind the
ballooned cusps
- focal calcifications
at the base of the posterior mitral leaflet
Histologic features:
- attenuation of fibrosa layer of valve
- focally marked
thickening of the spongiosa layer
- deposition of mucoid (myxomatous)
material
Immunophenotype:
Marker:
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Sensitivity:
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Specificity:
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Molecular features:
Other features:
- clinically mitral valve prolapse
References: