Diagnostic ultrasound ( PDFDrive )

1822 PART V Pediatric Sonography
longitudinal sonograms, the so-called “lying down” adrenal sign 217
(see Fig. 52.12).
In the older child and teenager, the adrenal gland is not easily
depicted by ultrasound, and other imaging modalities are preferable
for evaluation.
FIG. 52.67 Angiomyolipomas. Twelve-year-old boy with tuberous
sclerosis. Longitudinal gray-scale image demonstrates multiple hyperechoic
masses in keeping with angiomyolipoma (arrows).
Congenital Adrenal Hyperplasia
Congenital adrenal hyperplasia (CAH) is an inherited form of
adrenal insuiciency caused by autosomal recessive mutation of
genes that encode the production of enzymes involved in the
corticosteroid synthetic pathway. here is impaired synthesis of
cortisol by the adrenal cortex that results in an excessive accumulation
of androgenic precursors and adrenal gland enlargement.
he majority of cases are caused by a mutation of the CYP21A2
gene that leads to a deiciency of the 21-hydroxylase enzyme.
Infants may have salt-wasting, virilization of the external genitalia
in girls, and precocious puberty in boys. 218
A
B
C
D
FIG. 52.68 Multilocular Cystic Nephroma. A 10-month-old boy with large abdominal mass. (A) Longitudinal gray-scale image depicts a large
cyst (C) arising from the left kidney. The upper-pole calyces are dilated (arrows) secondary to obstruction by the cyst. (B) Longitudinal gray-scale
image reveals complex nature of the lesion with the large central cyst (C) and multiple smaller mural cysts (arrows). (C) Longitudinal color Doppler
image conirms the cystic, avascular nature of the lesion. (D) Axial intravenous contrast-enhanced computed tomography image reveals cyst (C)
surrounded by compressed renal parenchyma (arrows) and dilated posterior calyces (*).