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Figure 16.27 Rheumatic heart disease. A, Microscopic structure of the rheumatic valvulitis and a vegetation on the cusp of mitral valve in
sagittal section. B, Section of the myocardium shows healed Aschoff nodules in the interstitium having collagen, sparse cellularity, a multinucleate
giant cell and Anitschkow cells. Inbox shows an Anitschkow cell in cross section (CS) and in longitudinal section (LS).

interstitial tissue of the myocardium shows small foci of layers of the pericardium form fibrous adhesions resulting
necrosis. Later, tiny pale foci of the Aschoff bodies may in chronic adhesive pericarditis.
be visible throughout the myocardium. Microscopically, fibrin is identified on the surfaces. The
Microscopically, the most characteristic feature of subserosal connective tissue is infiltrated by lymphocytes,
rheumatic myocarditis is the presence of distinctive plasma cells, histiocytes and a few neutrophils.
SECTION III
Aschoff bodies. These diagnostic nodules are scattered Characteristic Aschoff bodies may be seen which later
throughout the interstitial tissue of the myocardium and undergo organisation and fibrosis. Organisation of the
are most frequent in the interventricular septum, left exudate causes fibrous adhesions between the visceral and
ventricle and left atrium. Derangements of the conduction parietal surfaces of the pericardial sac and obliterates the
system may, thus, be present. The Aschoff bodies are best pericardial cavity.
identified in the intermediate stage when they appear as
granulomas with central fibrinoid necrosis and are B. Extracardiac Lesions
surrounded by palisade of Anitschkow cells and Patients of the syndrome of acute rheumatism develop
multinucleate Aschoff cells. There is infiltration by lesions in connective tissue elsewhere in the body, chiefly
lymphocytes, plasma cells and some neutrophils. In the the joints, subcutaneous tissue, arteries, brain and lungs.
late stage, the Aschoff bodies are gradually replaced by
Systemic Pathology
small fibrous scars in the vicinity of blood vessels and the 1. POLYARTHRITIS. Acute and painful inflammation of
inflammatory infiltrate subsides. Presence of active the synovial membranes of some of the joints, especially the
Aschoff bodies along with old healed lesions is indicative larger joints of the limbs, is seen in about 90% cases of RF in
of rheumatic activity. adults and less often in children. As pain and swelling
3. RHEUMATIC PERICARDITIS. Inflammatory subside in one joint, others tend to get involved, producing
involvement of the pericardium commonly accompanies the characteristic ‘migratory polyarthritis’ involving two or
RHD. more joints at a time.
Grossly, the usual finding is fibrinous pericarditis in Histologically, the changes are transitory. The synovial
which there is loss of normal shiny pericardial surface due membrane and the periarticular connective tissue show
to deposition of fibrin on its surface and accumulation of hyperaemia, oedema, fibrinoid change and neutrophilic
slight amount of fibrinous exudate in the pericardial sac. infiltration. Sometimes, focal lesions resembling Aschoff
If the parietal pericardium is pulled off from the visceral bodies are observed. A serous effusion into the joint cavity
pericardium, the two separated surfaces are shaggy due is commonly present.
to thick fibrin covering them. This appearance is often
likened to ‘bread and butter appearance’ i.e. resembling the 2. SUBCUTANEOUS NODULES. The subcutaneous
buttered surfaces of two slices in a sandwich when they nodules of RF occur more often in children than in adult.
are gently pulled apart. If fibrinous pericarditis fails to These nodules are small (0.5 to 2 cm in diameter), spherical
resolve and, instead, undergoes organisation, the two or ovoid and painless. They are attached to deeper structures