Cardiac
lipomas are rare, benign tumours composed of adipose
tissue. These tumors are usually found in adult
patients but can affect patients of all ages.
Pathologists should be careful before making a firm diagnosis of
cardiac lipoma since normal fat deposition in the epicardium increases
with the advancing age.
Such
deposition is mainly seen in the anterior surface of the ventricles,
the anterior interventricular groove and along the apical course of
the coronary arteries.
Excessive
fat deposition is usually accompanied by fatty infiltration of the
myocardium of the right ventricle and interatrial groove.
Benign lipomatous tumours of
the heart include:
(i)
Solitary well
defined lipoma
and its variant intra
and intermuscular lipoma
(infiltrating lipoma).
Lipoma
and variants: click
- Multiple
large lipomas encircling the whole heart and compromising all cardiac
chambers is extremely rare.
-
Subendocardial lipoma (large polypoid mass) with intra-cavity
extension may cause valve stenosis or insufficiency.
(ii)
Lipomatous
hypertrophy of the atrial septum
is associated with
myocardial atrophy and fibrosis. This lesion usually causes cardiac
arrhythmias.
(iii)
Lipomatous hamartoma of atrioventricular
valve
involves both mitral and tricuspid valve and may involve papillary
muscle. It causes valvular insufficiency.
(iv)
Hibernomas
of heart and pericardium
have been reported .
Hibernoma: click
Clinical presentation :
True
lipomas remain asymptomatic and are detected at routine examination.
Extremely rare lipoma in children causes thickening of myocardial wall
with narrowing of cardiac cavity, and are usually associated with
tuberous sclerosis.
Gross
appearance :
Gross appearance depends
on the type of lipoma:
(i) Encapsulated lipoma.
(ii) Lipomatous hypertrophy
of the interatrial septum. It is usually seen as a bulge of the
superior limbus, covering the fossa ovalis by the protruding atrial
wall. Cut surface shows thick interatrial wall composed of
yellowish-gray adipose tissue infiltrating into the adjacent atrial
myocardium.
(iii) Valvular lipoma causes
deformity with localized thickening, which on cut surface appear as
adipose tissue.
Microscopic
features:
Visit: Lipomatous Tumours
Lipomas are
defined as circumscribed encapsulated tumours.
The tumours
consists of mature adipose tissue admixed with muscle cells, hence the
terms myolipoma, fibrolipoma, angiolipoma etc are related to these
features.
Lipomatous hypertrophy of
atrial septum shows displacement and atrophy of myocardial cells by
mature fat cells.
Islands of subendocardial
myocytes are entrapped in the lipoma.
Occasionally, mature fat
cells are intermingled with vacuolated, multiglobulat fat cells.
Sometimes, granular fat cells resembling fetal fat cells may be
present.
Valvular lipomas show
diffuse infiltration of mature fat cells with almost complete
replacement of normal tissue of the valve leaflets.
Visit:
Lipoblastoma
;
Angiolipoma
;
Chondroid lipoma
;
Spindle cell/pleomorphic lipoma
;
Liposarcoma
;
Cardiac Angioma
;
Cardiac Fibroma ;
Papillary
Fibroelastoma
.
REPORTING OF CARDIAC TUMOURS
|
