Granulomatous inflammation of the heart

Morphologic characteristics of granulomatous inflammation in the heart and pericardium are discussed. In rheumatic fever, two types of myocardial lesion are present--a nonspecific myocarditis and a specific lesion characterized by granulomas known as Aschoff's nodules. The latter undergo a cycle of development and resolution; in their mature stage, they contain Aschoff's cells which are uni- or multinucleated histiocytes with a serrated nuclear chromatin bar. Ultrastructural studies do not suggest a relationship between these cells and cardiac or smooth muscle cells. In metabolic disorders, granulomas occur in Farber's disease (lipogranulomatosis), gout (in which tophi are associated with calcific deposits and with a foreign body cellular reaction), the various syndromes of oxalosis (in which oxalate deposits also lead to a foreign body reaction), and in chronic granulomatous disease of childhood. Foreign body giant-cells can also be found in association with calcification of necrotic myocytes and in the syndromes of "cholesterol pericarditis." Well-developed granulomas occur in sarcoidosis, giant cell myocarditis, as a reaction to foreign bodies and devices implanted within the cardiovascular system, and in certain diseased caused by infective agents (tuberculosis, fungal and parasitic disorders). Infiltration of the heart by nongranulomatous masses of histiocytes can occur in Whipple's disease, Niemann-Pick disease, the hyperlipoproteinemias, Gaucher's disease, and in proliferative disorders of the mononuclear phagocyte system (juvenile xanthogranuloma, Chester-Erdheim syndrome, and malignant histiocytosis).