Diagnostic ultrasound ( PDFDrive )

1914 PART V Pediatric Sonography
M
A B C
FIG. 54.72 Sacrococcygeal Teratoma in 2-Year-Old Boy With Palpable Mass at Base of Spine. (A) Lateral radiograph of the pelvis shows
lack of coccygeal ossiication and large, retrorectal, soft tissue mass (M) with anterior displacement of the rectum. (B) Sagittal ultrasound shows
a solid mass (arrows) deep in the pelvis posteroinferior to the bladder. (C) Transverse ultrasound over the base of the spine posteriorly shows a
primarily solid mass (arrows) with one small cystic area extending deep into the pelvis.
A
B
FIG. 54.73 Sacrococcygeal Teratoma in Newborn Girl With Buttock Mass. (A) Sagittal sonogram demonstrates a large, cystic mass (C),
deep in the pelvis, posteroinferior to the uterus (U). The small amount of luid noted in the endometrial canal is secondary to residual material
hormonal stimulation. B, Bladder. (B) Transverse image over the base of the spine posteriorly demonstrates a complex mass (arrows) with a
predominantly large cystic (C) component.
undetected for longer periods than the large, exophytic masses. 49,228
Malignant teratomas are usually endodermal sinus tumors.
here is a wide spectrum of ultrasound appearances of
sacrococcygeal teratomas, ranging from purely cystic to mixed
or purely solid (Figs. 54.73 and 54.74). Calciications, seen in
one-third of cases, can be amorphous, punctate, or spiculated
and suggest the lesion is benign. Fat within the tumor appears
as bright areas of heterogeneous echogenicity. Large tumors may
displace and compress the bladder anteriorly and superiorly,
causing urinary retention and hydronephrosis.
Neuroblastoma and other neurogenic tumors can arise in
the presacral space in children. Five percent of neuroblastomas
arise in the pelvis. Because of their midline location, they are
considered stage III tumors. Pelvic neuroblastoma has a better
prognosis than intraabdominal neuroblastoma. he pelvic lesions
have a similar sonographic appearance to the adrenal lesions.
hey are solid, echogenic, heterogeneous masses with a 70%
incidence of calciication. Areas of cystic necrosis and hemorrhage
are uncommon 229,230 (see Fig. 54.74).
Rhabdomyosarcoma arising from the pelvic musculature can
manifest as a solid presacral mass. It is usually an iniltrating
tumor with poorly deined margins. Anechoic spaces within a
predominantly solid mass suggest areas of necrosis and hemorrhage.
Calciication is rare. 229 Ultrasound is an excellent method
for identifying and staging rhabdomyosarcoma arising from the
genitourinary tract. However, computed tomography (CT) and
MRI provide more complete information for those tumors arising
from the pelvic side walls. Other predominantly solid presacral