Quadricuspid Right Atrioventricular Valve: A Cadaveric Case Report.

Quadricuspid heart valve anomalies are rare congenital malformations, typically affecting the aortic valve; involvement of the right atrioventricular (tricuspid) valve is exceedingly uncommon. Embryologically, the tricuspid valve forms through complex fusion and delamination processes involving the endocardial cushions.  This case describes a quadricuspid right atrioventricular valve identified during routine cadaveric dissection in an elderly male. Gross examination revealed four distinct cusps and an accessory papillary muscle, along with right atrial dilation, near-complete atrophy of the right auricle, right ventricular hypertrophy, and evidence of poor valve coaptation. These findings, combined with signs of cardiomegaly, suggest significant valvular dysfunction during life, likely contributing to chronic tricuspid regurgitation. During the gross examination, valvular distortion was noted, highlighting the potential for secondary degenerative changes superimposed upon congenital structural anomalies, particularly in the elderly. Recognition of such anomalies is essential, as they may predispose individuals to valvular incompetence, right-sided heart dysfunction, and other clinical complications. Early identification and characterization of these rare malformations may influence clinical management and surgical decision-making.