Case report:
A 15-month-old girl was admitted to the hospital with a chief complaint
of pulmonary artery stenosis found during the foetal period and cardiac
murmur found after birth. Her vital parameters were normal; there was no
cyanosis, and oxygen saturation (SpO2) was 98% in room
air. There was no history of trauma or infection.
Initial examination revealed a systolic murmur at the left sternal edge
and clear lung fields, with no lower limb oedema. Transthoracic
echocardiography showed a 9.6 mm x 9.2 mm nearly circular abnormal
cystic
mass in the main pulmonary artery adherent to the pulmonary valve
(Figure 1(a)). The pulmonary valve appeared thickened and restricted,
with a peak gradient of 61 mmHg, consistent with valvular pulmonary
stenosis. Transthoracic echocardiogram examination also revealed a
secundum-type atrial septal defect (ASD) with a diameter measuring 21
mm. In addition, the patient had right heart enlargement and mild
tricuspid regurgitation.
The mass was excised through a right thoracotomy under cardiopulmonary
bypass. The pulmonary valve orifice was not narrowed, the left anterior
valve was lengthy, and the right anterior valve was slightly stiff. The
tumour was a sessile cyst with a diameter of 1 cm. It was attached to
the left posterior valve and prolapsed into the pulmonary artery. The
impression of the surgeon was that the tumour originated from the
pulmonary valve, and he could find a clear cleavage (Figure 1(b)). The
tumour was completely resected macroscopically. The atrial septal defect
was closed by a Gore-Tex patch.
Histological examination of the lesion confirmed the diagnosis of
lipoblastoma. Lobules of mature as well as immature fat cells,
signet-ring cells, and multivacuolated cells of varying degrees of
differentiation can be seen under the microscope. In contrast to myxoid
liposarcoma which concentrated peripherally, mature fat cells are
concentrated in the central portion of the lobule (Figure 2(a)).
Immunohistochemical results showed positive immunostaining for CD34 and
S-100 (Figure 2(b)).
The postoperative period was uneventful, and the patient was
asymptomatic thereafter. When seen 2 months later, echocardiogram showed
no pulmonary valvular incompetence. On further follow-up, there was no
recurrence.