Aschoff's bodies or nodules
are characteristic lesion of acute rheumatic fever.
These are usually
located in the interstitial tissue of the heart, specially in the
myocardium and the endocardium often close to small blood vessels.
Occasionally, they are present in the pericardium.
These have been
described in the adventitia of the aorta.
Lesions elsewhere in the body
may be suggestive of but should not be confused with Aschoff bodies.
have been found in a significant proportion of atrial appendages.
nodules are globular, elliptic, or fusiform microscopic structures.
There are three
phases in the development of the Aschoff body :
1. Early (exudative,
2. Intermediate (proliferative
or granulomatous) phase:
3. Late (fibrous
or healing) phase:
In the granulomatous stage of the lesion the Aschoff body is identifiable and is
regarded as pathognomonic for rheumatic carditis.
The early phase of
the life cycle of the Aschoff body occur upto the fourth week of acute
rheumatic fever is representated by exudative degenerative and fibrinoid
changes in the collagenous tissue.
intermediate phase which is evident during the fourth to the thirteenth
week of the disease swelling and fragmentation of collagen fibres and
fibrinoid change are present in the nodule, but cellular proliferation is
the main feature. There is accumulation of Anitschkow cells.
These are large mononuclear cells that are found in normal hearts but are
increased in number in Aschoff bodies.
By themselves they do not
represent a specific response to rheumatic fever.
The caterpillar chromatin pattern
of the nucleus in longitudinal section and owl-eye appearance in
transverse section characterize the Anitschkow cell of Aschoff bodies in
rheumatic heart disease.
(modified Anitschow cells):
large cells with abundant basophilic cytoplasm ragged cell borders and one
to four nuclei.
usually seen are lymphocytes , plasma cells and occasional neutrophils. As
this phase progresses, the exudative and fibrinoid alterations gradually
In 3 to 4 months
the healing phase is reached charcterized by regression and fibrosis of
The Aschoff body
is elongated or fusiform, the cytoplasm of the component cell is
diminished in amount, the cells become elongated and spindle-shaped.
Often fibrillar material appears between the cells, crowding them into rows.
The collagenous fibers fuse to form dense collagenous bundles resulting in
small scars between muscle bundles.
immunohistochemical analysis of the Aschoff lesions in rheumatic fever,
combining immunohistochemical analysis with comparative morphology,
permitted the division of the Aschoff nodules into three stages:
(1) Aschoff nodule
without admixed lymphocytes,
nodules with a few T lymphocytes, and
nodules containing many admixed lymphocytes of both B- and T-cell
It was postulated that the
order of progression was from stage 1 with macrophages only, to
accumulation of first T lymphocytes (stage 2) and then B lymphocytes
The nature of Aschoff body
is a controversial subject:
1) It is a generally
accepted view that changes that changes in the ground substance and
collagen fibers are primary and precede the formation of Aschoff cells.
The Anitschkow cell from
which Aschoff cell is derived is considered to be a cardiac histiocyte.
2) According to other
investigators Aschoff bodies originate and evolve from primary injury to
muscle cells in the heart.
In this view Aschoff
bodies are lesions of small groups of heart muscle fibers interspersed
among other uninvolved bundles of heart muscle fibers.
Anitschkow and Aschoff
cells are considered to be derived from cardiac myocytes rather than
connective tissue cells.
Endocardial Aschoff bodies
are considered to be lesions of smooth muscle cells which normally occur
in the zone between endothelium and myocardium.
3) According to some
authors the Aschoff bodies are derived from diseased lymphatic vessels.
In this view,
proliferation of the endothelial cells of lymphatics give rise to the
4) Finally according to
some investigators Aschoff bodies are derived from nerves and they have
observed close anatomic relationship between nerves and Aschoff bodies.