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ABDOMINAL ULTRASOUND
peak incidence before 5 years of age. It occurs in
various sites throughout the body.
Other causes of focal liver lesions
Liver metastases may occur from most paediatric
malignancies, particularly neuroblastoma, rhabdomyosarcoma
and Wilms’ tumour (p. 229).
Leukaemia and lymphoma may also cause focal
defects in the liver. Liver involvement may be manifested
by hepatomegaly with normal liver texture,
a non-specific sign, or by diffuse coarsened liver
texture with or without hepatomegaly.
Haemangioendothelioma
Vascular tumours account for most benign liver
tumours in childhood, with haemangioendotheliomas
being seen more frequently than cavernous
haemangiomas. Although haemangioendothelioma
may be asymptomatic, infants generally present
before the age of 6 months with an abdominal
mass, respiratory distress, anaemia and cardiac failure,
caused by the shunting of blood from the
aorta through the tumour. Large tumours may
bleed spontaneously, resulting in haemoperitoneum.
They may present with jaundice and
increased transaminase levels and 50% of children
also have cutaneous haemangioma. 10
These tumours are generally multiple, of varying
echogenicity and may have a complex echotexture
due to thrombus, calcifications and internal septations
(Fig. 9.3B). The vascular nature of these
lesions is demonstrated by a large coeliac axis and
marked decrease in the size of the aorta below the
origin of the coeliac axis. The main differential
diagnosis of multiple haemangioendothelioma is
from metastatic liver disease, particularly from disseminated
neuroblastoma.
Although most asymptomatic paediatric haemangioendotheliomas
regress spontaneously, those
complicated by cardiac failure require active treatment.
Steroids may be administered and serial
ultrasound scans may be used to monitor the gradual
resolution of the lesion. Angiographic
embolization or surgical ligation of the major
feeding vessels of the hepatic artery may be necessary
in severe cases that fail to respond to steroid
therapy.
PANCREAS
Normal appearances
The acoustic characteristics of the pancreas vary
with age. Pancreatic echogenicity is quite variable
and is occasionally hypoechoic in neonates compared
with the adult gland. In older children
echogenicity is equal to or slightly greater than
that of the liver. The pancreas is relatively larger in
young children than in adults, gradually increasing
with age, reaching adult size in late teens. 11 The
pancreatic duct is often visualized but should not
be greater than 2 mm in width. The relative
hypoechogenicity and relatively larger size of the
normal pancreas in childhood should not be misinterpreted
as a sign of probable pancreatitis when
scanning a child with abdominal pain (Fig. 9.4).
Pathology of the pancreas
Pancreatic abnormalities are relatively uncommon
in childhood. Most ultrasound abnormalities are
the result of infiltrative processes associated with
other syndromes or diseases (Table 9.1). Focal
pancreatic lesions are rare.
Ultrasound is an ideal investigation for evaluating
the paediatric pancreas, as a high-frequency
Figure 9.4 Normal pancreas in a 13-year-old girl—
relatively hypoechoic and bulky in comparison with the
adult gland.