Aschoff bodies in the myocardium are the hallmark of carditis associated with

Acute rheumatic fever is characterized by discrete inflammatory foci within a variety of tissues. The myocardial inflammatory lesions--called Aschoff bodies--are pathognomonic for rheumatic fever these are collections of lymphocytes (primarily T cells), scattered plasma cells, and plump activated macrophages called Anitschkow cells occasionally punctuating zones of fibrinoid necrosis. The Anitschkow cells have abundant cytoplasm and central nuclei with chromatin condensed to form a slender, wavy ribbon (so-called caterpillar cells). During acute rheumatic fever, Aschoff bodies can be found in any of the three layers of the hea--pericardium, myocardium, or endocardium (including valves). Hence, rheumatic fever is said to cause pancarditis. (Robbins Basic pathology,9th edition.pg no.391)