Aschoff bodies in an operatively excised mitral valve.

Aschoff bodies are granulomatous lesions believed to be pathognomonic of rheumatic fever. Most histologic descriptions have been limited to locations adjacent to or within the myocardium. Aschoff bodies within valves are uncommon findings. We report a case showing the typical granulomas in an excised mitral valve. We suggest that Aschoff bodies can, and do, occur in valve tissue during acute rheumatic carditis and that structural differences between valves and typical intramyocardial locations, variations in frequency and strength of individual infections, individual host responses, and time intervals between infection and histologic examination often obscure their findings in valves.