<prompt> Antischkow cells are seen in -Infective endocarditisMyocardial infarctionRheumatic myocarditisNone  <response>: Aschoff body Fig. 15.13: It is spheroidal or fusiform characteristic lesion seen in rheumatic disease. Site: During acute RF, may be found in any of the three layers, in the perivascular interstitial region of the hea. Formation of Aschoff body consists of 3 phases: Earlyexudative phase: It consists of a perivascular focus of swollen eosinophilic collagen surrounded by lymphocytes, plasma cells, and macrophages. Intermediategranulomatous phase: It is pathognomonic of rheumatic myocarditis. It is a granulomatous lesion, with a central fibrinoid focus associated with lymphocytes primarily T-cells, macrophages, Anitschkow cells pathognomonic for RF and occasional plasma cells. Anitschkow cells are plump activated macrophages, which have abundant cytoplasm. They have round-to-ovoid nuclei in which the chromatin is disposed of in a central, slender, wavy ribbon. These nuclei resemble a caterpillar when cut longitudinally hence known as caterpillar cells. On cross section, these nuclei have an owl-eye appearance. Few Anitschkow cells may become multinucleated with 2 to 4 nuclei in which case, they are termed Aschoff giant cells. Latehealed final phase: Aschoff body is replaced by a nodule of scar tissue. 