Pediatric emergency medicine trisk 948
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liver; N, node; S, stomach. B: Celiac axis neuroblastoma. Enhanced CT section of the abdomen
at level of the kidney shows a large lobulated mass with irregular margins and calcification
displacing the right kidney inferoposterior and laterally. Note encased inferior vena cava (IVC)
and aorta. The IVC is displaced laterally and ventrally and to the right the superior mesenteric
artery and celiac axis are completely surrounded by the mass. A, Aorta; I, IVC; K, kidney; L,
liver; S, spleen; white arrows, mass.
Wilms Tumor
Wilms tumor is the most common intrarenal tumor seen in children. The tumor
can be massive before its discovery. Wilms tumor should be considered in any
child who has unexplained hematuria.
A solid renal mass demonstrated by US in infants and children is usually a
Wilms tumor. Because of the high frequency of tumor extension into the renal
veins and inferior vena cava, these vascular structures should be examined by US.
Because Wilms tumors are usually large and expansive, the inferior vena cava
often is extrinsically displaced by the tumor mass. CT with bolus contrast
enhancement may be required for confirmation of equivocal invasion in a patient
suspected of having Wilms tumor. CT scan can define the presence of an
intrarenal mass and extent of tumor, visualizes vascular structures, identifies
nodal involvement, defines internal hemorrhage and necrosis, evaluates the
presence or absence of liver metastases, and provides some measure of renal
excretory function. Also, CT can determine whether a tumor is initially
nonresectable or bilateral ( Fig. 116.24 ). Chest CT is also performed at the initial
evaluation to identify pulmonary metastases.
FIGURE 116.24 A: Bilateral Wilms tumor. A 5-year-old girl with left flank mass. Computed
tomography (CT) sections of the upper abdomen with contrast medium enhancement show a
necrotic mass arising from superior aspect of the left kidney. Note a small mass in the superior
medial aspect of the right kidney. B: Bilateral Wilms tumor (same patient as in A ). CT section
of the abdomen with contrast medium enhancement shows extent of the large necrotic left
Wilms tumor with periaortic adenopathy.
Rhabdomyosarcoma
Rhabdomyosarcoma can occur anywhere in the abdomen or pelvis where there is
striated muscle. Tumors are particularly common in the pelvis, involving the
prostate, uterus or vagina, and retroperitoneal structures, but they have also been
found in the common bile duct and other unusual sites. These tumors can reach a
large size before they become symptomatic, and each must be managed
individually, depending on the site of origin, extent of growth, and the degree of
spread.
Hepatomas
The most common primary GI tract neoplasm is hepatic in origin.
Hepatoblastoma and hepatocellular carcinoma are the two main subgroups of
liver tumors; they are clinically indistinguishable at presentation. Many are
asymptomatic, but symptoms such as early satiety, weight loss, and abdominal
pain may be seen, especially with very large tumors. More often, the tumor is
discovered after caregivers notice a change in the appearance of the abdomen.
They are usually seen in older infants and young children. Increased levels of
alpha-fetoprotein are associated with both types. Differential diagnosis should
include hemangioendothelioma, hamartoma, and renal and adrenal tumors.
These tumors are often initially diagnosed with US. Further radiologic imaging
is directed at diagnosis and the resectability of the tumor. CT or MRI with
angiography is often required to determine surgical approach ( Fig. 116.25 ).
Long-term survival is poor unless complete resection is possible. Liver tumors
commonly metastasize to the lungs, brain, and regional nodes.
FIGURE 116.25 A: Hepatoblastoma in a 2-month-old boy. Axial T1 magnetic resonance
imaging (MRI) shows a solid mass (M ) occupying the entire liver, gallbladder (arrow ), and
right kidney (K ). B: Coronal magnetic resonance angiography shows liver mass (M ), with
