| Syn:
Idiopathic Giant Cell
Myocarditis
Image
Link1
;
Image Link2
;
Image Link3
;
Image Link4
.
Giant cell myocarditis
(GCM) is a rare inflammatory disease of the myocardium that
often affects previously healthy young adults.
Visit:
Myocarditis.
It is usually fatal without treatment, and may respond to
aggressive medical and surgical therapy.
GCM is most often
progressive over days to weeks and frequently requires the concurrent
management of congestive heart failure, tachyarrhythmias, and heart
block.
Gross:
Gross appearance of the heart is not unlike that seen in myocarditis
associated with known infectious agents, the essential features being
dilatation and sometimes hypertrophy. When the lesions are extensive,
they appear as yellow-gray or gray foci throughout the myocardium.
Mural thrombi are commonly present.
Microscopic features:
After common causes of heart disease are excluded, the
diagnosis must be confirmed by endomyocardial biopsy.
Image
Link1 ;
Image Link2 ;
Image Link3 ;
Image Link4
Histologic findings,
of widespread or multifocal serpiginous necrosis with mixed
inflammatory infiltrate composed of lymphocytes and
histiocytes are considered diagnostic. The presence of
eosinophils is noted in most cases. Admixed with the
infiltrate are multinucleated giant cells in the absence of
sarcoid-like granuloma.
The giant cells are
of the foreign body and Langhans types, but some giant cells of
myogenic origin also may be present.
Differential diagnosis:
Granulomatous
inflammation of the heart:
Rheumatic fever-
A specific lesion
characterized by granulomas known as Aschoff's nodules (they contain
Aschoff's cells which are uni- or multinucleated histiocytes with a
serrated nuclear chromatin bar).
Rheumatic
myocarditis is characterized by the presence of interstitial Aschoff's
nodules adjacent to small intramyocardial arteries, and an absence of
widespread necrosis.
Well-developed granulomas
occur in sarcoidosis -
(i) Absence of
well formed granulomas in GCM. (ii) The lack of involvement of the
epicardial fat in GCM . In cardiac sarcoidosis, granulomas are seen in
the epicardial fat. (iii) Prominent eosinophilia in the inflammatory
cellular infiltrate present in GCM. It is usually absent in cardiac
sarcoidosis.
Infectious
granulomatous myocarditis :
Granulomas are noted in
lesions caused by infective agents (tuberculosis, fungal and
parasitic disorders).
Necrotizing
granulomas in infectious conditions should be excluded with
histochemical stains and cultures. Acid-fast bacilli and spirochetes
cannot be demonstrated.
Idiopathic
lymphocytic myocarditis : Giant cells are
usually not prominent.
Absence of widespread necrosis.
Other conditions:
In metabolic
disorders-
Granulomas occur in 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.
Reaction to foreign
bodies: Granulomas
occur as a reaction to foreign
bodies and devices implanted within the cardiovascular system.
Treatment:
Treatment includes immunosuppressives,
and the indication for cardiac transplantation should be evaluated
early, as there is an increased risk of recurrence in the graft.
|
