Autopsy of a 30-year-old woman who died suddenly shows ballooning of both mitral leaflets into the left atrium with elongated, thinned chordae tendineae. Microscopy of the leaflets shows expansion of the spongiosa layer by loose myxomatous material rich in proteoglycans. The most likely diagnosis is:

• A Chronic rheumatic mitral stenosis
• B Libman-Sacks endocarditis
• C Non-bacterial thrombotic endocarditis
• D Mitral valve prolapse with myxomatous degeneration ✓

Explanation

Mitral valve prolapse, or Barlow syndrome, is defined by myxomatous degeneration in which the spongiosa expands with accumulated proteoglycans, weakening the fibrosa and allowing billowing of leaflets, often with elongated chordae prone to rupture. Rheumatic disease instead causes fibrous thickening with commissural fusion and stenosis. Libman-Sacks and marantic vegetations are discrete deposits on valve surfaces, not intrinsic myxomatous leaflet change, eliminating C and B.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.