CASE REPORT
The patient was a male newborn and his prenatal echocardiographic
examination in antenatal 27th week revealed huge
hypoechogenic mass involving the left ventricular free wall and left
atrium with the largest diameter of 5 cm. The left ventricular chamber
was quite small, with no other intracardiac pathology of the fetus.
There was a systolic murmur in the aortic area on postnatal examination.
Heart sounds were deeply heard. The chest roentgenogram revealed a
marked enlargement of the cardiac shadow. Postnatally, echocardiography
showed a huge tumoral mass of the heart consisting anterolateral,
lateral, apical and posterior part of the left ventricle, the mass
involved also the left atrial wall. The right ventricle, right atrium,
aorta, and pulmonary artery were normal. The pericard was presented
free. The left ventricle was small, and volume was decreased. Clinical
examinations results and family records have any evidence of tuberous
sclerosis.
The patient, who developed cardiorespiratory distress immediately after
birth and symptoms of low cardiac output with a heart rate of below 100
beats per minute, blood pressure of below 40/25 mmHg and anuria, had
endotracheal intubation, mechanical ventilation and inotropic support.
Macroscopically, a large, solid and white epicardial mass was observed
which was located on the anterolateral and inferior wall of the heart
involving the apical part (Fig 1a). The left lung was quite hypoplastic.
Operation performed under partial cardiopulmonary bypass and moderate
hypothermia, considering that the mass may have myocardial involvement.
A biopsy from the white, solid and well-circumscribed tumor was
performed for an intraoperative examination. The remaining lobulated
mass was dissected from the epicardium, three separate solid masses
attached to each other were detected and excised (Fig 1b). The left
anterior descending coronary artery extrinsically compressed by tumor
dissected carefully without damage. Left ventricular free wall stayed
deplaced to the interventricular septum after total resection of masses.
Sternum could not be closed due to cardiac edema and left the patient
open chest.
The histopathological examination revealed several vacuolated
eosinophilic cells with radial cytoplasmic extensions, known also as
“spider cells” (Fig 2a). Anti-desmin immunopositivity leads us to
diagnose the case as a cardiac rhabdomyoma with the presence of typical
histopathological features (Fig 2b, Fig 3).
Left ventricular ejection fraction was measured as 30% after operation.
Left ventricular volume was same as before operation. The patient died
on the first postoperative day due to low cardiac output despite
inotropic support.
DISCUSSION
Rhabdomyomas are the most common fetal cardiac tumor and usually
associated with tuberous sclerosis but may be sporadic (1-2).Rhabdomyomas are frequently diagnosed by means of fetal echocardiography
during the prenatal period. The prognosis of patients with rhabdomyomas
is dependent on the number, size and location of the lesions as well as
the presence or absence of associated anomalies (3-4). Tumors larger
than 20 mm in diameter are more likely to cause hemodynamic disturbances
or arrhythmias, which are associated with an increased risk of death
(5). Associated congenital heart defects; hypoplastic left heart,
tetralogy of Fallot and endocardial fibroelastosis have been reported
(5-7). Extracardiac anomalies such as cleft palate, polycystic kidney
and coexistence with chromosomal anomalies were also detected (5).
As a histological point of view, glycogen storage disease, histiocytoid
cardiomyopathy and granular cell tumor are the main differential
diagnosis of cardiac rhabdomyoma. The formation of distinct tumor
nodules, the absence of epicardial surface involvement alone and the
presence of radial cytoplasmic extensions in vacuolated cells (known
also as spider cells) are the main morphological clues for diagnosing
cardiac rhabdomyoma. Furthermore, the strong relationship with tuberous
sclerosis manifesting with intracranial hamartoma, facial angiofibroma,
linear epidermal nevi, renal angiomyolipoma and other hamartoma types
should be kept in mind in patients diagnosed as cardiac rhabdomyoma.
Most patients can be managed conservatively, because they typically
regress spontaneously with no hemodynamic effect (8). More recently,
medical treatment with mammalian target of rapamycin (mTOR) inhibitors
such as everolimus and sirolimus which act on a protein kinase that
regulates cell growth, proliferation, protein synthesis, and
transcription has been increasingly used with rapid regression of
rhabdomyomas (9-10).
Rhabdomyomas that obstruct the inflow or ventricular outflow tracts or
that alter valve function and lead to regurgitation also carry a poor
prognosis and some patients need immediate surgical intervention in the
early postnatal period (1,8). Patients with large rhabdomyomas which
are significantly associated with poor outcome, should be aware of the
nature of their particular tumors and the type of surgical procedures
available for treatment.