CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 7, August 2012
AFRICA
e11
case illustrates a classic colonic adenocarcinoma with distant
metastases. The cardiac mass was most likely a metastatic
tumour.
Discussion
The most common sites of colorectal carcinoma metastases
are the liver and lungs. Cardiac metastases from primary
colorectal carcinomas are extremely rare. Tumours that more
often metastasise to the heart are carcinomas of the lung and
breast, mesotheliomas, melanomas and lymphomas.
7
Klatt and Heitz studied a total of 1 029 autopsies from
patients diagnosed with malignancies.
4
They found cardiac
involvement in 10.4% of all cases; 36.4% of them originated
from adenocarcinoma of the lung, gastrointestinal tract, female
genitourinary tract, breast or pancreas.
4
The incidence was
similar to that of an earlier study by Goudie
et al.,
which reported
10% of cardiac metastases in autopsies of cancer-related deaths.
5
Right-sided cardiac involvement, especially in the right
ventricle, is more common than in the left chambers.
8
The reason
for this has not been well established. In this patient a mass,
which was most likely the metastasis, was found in the right
atrium causing obstruction to the right ventricular inflow.
In clinical practice, the most frequent form of cardiac
metastasis is pericardial seeding, which may lead to pericardial
tamponade. Metastasis to the endocardium is infrequent.
9
This
however may cause haemodynamic embarrassment, resulting
in heart failure, as seen in our case. Generally, when the
endomyocardium is involved, pericardial effusion is seen.
However, in our case, pericardial effusion was not present.
Two-dimensional echocardiography is the initial investigative
modality for the detection of intra-cardiac mass as well as
pericardial effusion, as it has high sensitivity and specificity.
10
Nowadays additional cardiac computed tomography andmagnetic
resonance imaging are necessary to give adequate radiological
assessment. These modalities may help to differentiate the intra-
cavity mass from organised thrombus surrounding the mass. In
addition, information from Doppler echocardiography, magnetic
resonance imaging or thoracic radionuclide scanning may aid
in differentiating a thrombus from a solitary intra-cardiac mass.
These modalities may assist in detecting the presence or absence
of haemosiderin deposits in the mass, thereby differentiating an
intra-cardiac mass from a thrombus.
Cardiac magnetic resonance imaging shows in detail the
location, insertion site and size of the tumour which will
facilitate surgical resection. Tissue characterisation and signs of
neovascularisation provide crucial information to differentiate
between a tumour and thrombus if uncertainty arises after
echocardiography. Multi-detector cardiac computed tomography
or coronary angiography are the investigations of choice to
identify concomitant coronary artery disease or anomalies prior
to surgery.
In our case, the concurrent findings of extensive sigmoid
colon carcinoma and an infiltrative mass in the right atrium
made metastatic intra-cardiac metastasis the most likely
diagnosis. However, the lack of evidence due to unavailability
of histopathological analysis made this conclusion uncertain.
Although double pathology is rare, other differential diagnoses
such as myxoma, thrombus or other primary cardiac tumour
should still be entertained.
The advancement in anti-cancer treatments and progress
in diagnostic modalities have generally improved the survival
rate of cancer patients. Therefore the frequency of intra-cardiac
involvement would be expected to be higher. The possibility
of developing metastatic disease in an infrequent site may also
be increasingly seen in clinical practice. Early diagnosis and
curative surgical resection may prevent progression and sudden
cardiac death.
In a patient with symptoms and signs of valvular obstruction
such as in this patient, surgical intervention may be indicated.
This may help to relieve the obstructive symptoms and lead to
prolongation of life expectancy in such a patient. A palliative
symptomatic approach may be adopted to obviate the mortality
risk in patients such as ours.
11,12
Our patient had unfortunately
succumbed before any intervention could be carried out.
Koizumi
et al
. reported a case of obstructive cardiac metastasis
Fig. 1. A section of the sigmoid colon biopsy which
showed the moderately differentiated adenocarcinoma x
40 magnification.
Fig. 2. Two dimensional transthoracic echocardiogram
showing the solitary homogenous mass in the right atri-
um with obstruction of the right ventricular inlet. (White
arrows delineate the margins of the mass.)
