Diagnostic ultrasound ( PDFDrive )

1862 PART V Pediatric Sonography
Abdominal desmoid tumors are a rare, benign type of tumor
that can occur as a mass or masses in the mesentery, abdominal
wall, retroperitoneum, and pelvis. here is an association with
Gardner syndrome, and these will not have metastatic lesions.
Gastrointestinal stromal tumors rarely occur in the pediatric
population and have a propensity to occur in females with a
mean age of 12.6 years. 160 hey arise in the muscularis propria,
most commonly in the antrum and body of the stomach. Internal
cystic areas are common and can represent hemorrhage or
necrosis.
Sonography does not play a major role in the evaluation of
GI neoplasms, but masses or polyps may be identiied in some
patients when the bowel is illed with luid. 82,161 More oten,
intraluminal GI masses in children manifest with obstruction
caused by intussusception. he mass that acts as a lead point for
the intussusception may not always be sonographically discernible.
Most solid tumors appear with a variably echogenic pattern and
cannot be reliably distinguished by their sonographic characteristics.
45,162-164 Lymphoma tends to be hypoechoic and may be
associated with ulceration. he tumors most likely to appear
FIG. 53.45 Mesenteric Adenitis/Ileitis. Thickened mucosa in a small
bowel loop (large arrow) with a normal appendix nearby (small arrow).
predominantly cystic are teratomas and lymphangiomas. 165-169
Abdominal lymphangiomas most frequently occur in the
mesentery and can appear as solitary cysts or as multiloculated
cystic masses 168 (Fig. 53.48A-B). Gastrointestinal teratomas
usually have large cystic components, but echogenic fat and
calciications are also oten visible 165,167,168 (Fig. 53.48C). Hemangiomas
may involve the mesentery and are usually associated
with hypervascularity and large feeding vessels.
PANCREAS
Normal Anatomy and Technique
he pancreas is easily imaged in children and normally appears
relatively generous in size compared with the pancreas of an
adult. he normal echotexture of the pancreas in childhood is
homogeneous and most oten isoechoic or hyperechoic compared
with the liver. he normal pancreatic duct is usually not visible
sonographically, unless a high-resolution linear transducer is
used.
Pancreatitis
Pancreatitis is less common in children than in adults and is
more likely to be acute rather than chronic. he most common
causes of acute pancreatitis in children include blunt abdominal
trauma (including abusive abdominal trauma), viral infection,
and drug toxicity. Regardless of the cause, sonographic indings
are usually sparse unless a complicating pseudocyst arises. he
most common abnormal sonographic inding is pancreatic
enlargement (Fig. 53.49A), but a normal-sized pancreas does
not exclude the diagnosis. Decreased echogenicity of the pancreas
can occur with pancreatitis, 170,171 but this is a diicult inding to
substantiate because of the variable echogenicity of the normal
pancreas in children. 171 Occasionally, increased echogenicity of
the pararenal space may be encountered, the result of lipolysis
of normal fat by pancreatic enzymes that have leaked into the
hepatorenal space. 172
Chronic or recurrent pancreatitis in children is most
likely caused by congenital abnormalities afecting the biliary
tract (e.g., choledochal cysts, pancreas divisum, cystic
A
B
FIG. 53.46 Other Conditions Resembling Appendicitis. (A) Inlamed Meckel diverticulum. Transverse ultrasound of the right lower quadrant
in a child with clinically suspected acute appendicitis. (B) Profound mesenteric inlammation in the region of the appendix was actually caused by
Crohn disease (arrows). The appendix was normal.