Diagnostic ultrasound ( PDFDrive )

1908 PART V Pediatric Sonography
A
B
FIG. 54.61 Distal Ureter Stone. This 14-year-old patient had hematuria and right lank pain that radiated to the right groin. Mild right-sided
hydronephrosis (not shown) was present. (A) Small stone (arrow) is lodged in the mildly dilated distal ureter, with distal acoustic shadowing.
(B) Color Doppler shows “twinkle” artifact, conirming the presence of a stone.
on the midanterosuperior surface of the distended bladder.
Involution of the urachus is not complete at birth and can be
followed on sonography during the irst months of life. hus
young infants with a discharging umbilicus or an infected urachus
may beneit from a conservative approach using serial sonography
as a guide because sonography can document spontaneous
involution as well as abnormal development. 10 here are four
types of urachal anomalies: patent urachus (completely open
urachal lumen associated with urinary drainage from umbilicus),
urachal sinus (opening to umbilicus), urachal diverticulum
(opening to bladder), and urachal cyst (urachus obliterated at
both ends with extraperitoneal position of isolated cyst) 213 (Fig.
54.62). Two sonographic patterns have been described in urachal
anomalies: (1) a cystic mass, oten with internal echoes or septations
caused by infection, and (2) an echogenic, thickened, tubular
sinus tract (8-15 mm in diameter). 213
Other anomalies of the lower urinary tract that can be identiied
on ultrasound include ectopic pelvic kidney, seminal vesicle
cysts (Fig. 54.63), müllerian duct (prostatic utricle) cysts (Fig.
54.64), and congenital or acquired bladder diverticula. 214
Infection
UTIs are common in children, especially girls, and are usually
the result of cystitis. Clinically, these children have urinary
frequency, incontinence, dysuria, and/or hematuria. 215,216 he
UTI is usually bacterial. Hemorrhagic cystitis can develop
secondary to a viral infection (Fig. 54.65), chemotherapy with
cyclophosphamide, or indwelling catheters. Granulomatous
cystitis in a patient with chronic granulomatous disease of
childhood can be detected on ultrasound. On sonography, the
bladder may appear normal in mild cases of cystitis. More speciic
signs of cystitis are difuse or focal bladder wall thickening and
irregularity (Fig. 54.66). Echogenic material in the bladder lumen
may represent purulent or hemorrhagic urine. Bladder calculi
are more common with Proteus or Pseudomonas infections. With
cystitis cystica or cystitis glandularis, rounded, isoechoic or
hypoechoic, polypoid lesions may protrude into the lumen,
mimicking a bladder tumor (Fig. 54.67). Rosenberg and colleagues
217 reported that in children with hematuria, dysuria, and
frequency plus cystographic or sonographic demonstration of a
bladder with reduced capacity and circumferential wall thickening,
or sonographic indings of isoechoic bladder wall thickening
(focal, multifocal, or circumferential distribution), intact mucosa,
and bullous lesions, these indings should strongly suggest
inlammation and not malignancy. In addition, changing mass
contour and thickness with increasing bladder illing are particularly
suggestive of inlammatory thickening. When an
inlammatory lesion is suspected, follow-up imaging should be
performed in 2 weeks, which will preclude biopsy if indings are
normal. 217
Neoplasm
Rhabdomyosarcoma is the most common tumor of the lower
urinary tract in children, with 21% arising from the genitourinary
tract. he most frequent primary sites are the bladder trigone
or prostate. Less frequent sites of origin are the seminal vesicles,
spermatic cord, vagina, uterus, vulva, pelvic musculature, urachus,
and paratesticular area. 44,218 here is a male predominance of
1.6 : 1. he peak incidence occurs at 3 to 4 years of age; a second,
smaller peak is seen in adolescence. he most common rhabdomyosarcoma
cell type is the embryonal form, of which sarcoma
botryoides is a subtype. he alveolar form is next in frequency;
undiferentiated and pleomorphic types are uncommon. Tumors
arising from the bladder, prostate, or both usually manifest early
with symptoms from urinary tract obstruction and hematuria.
Rhabdomyosarcoma has been reported to be associated with
neuroibromatosis, fetal alcohol syndrome, and basal cell nevus
syndrome.
On sonographic examination, rhabdomyosarcoma appears
as a homogeneous, solid mass with an echotexture similar to