Diagnostic ultrasound ( PDFDrive )

CHAPTER 54 Pediatric Pelvic Sonography 1901
A
B
FIG. 54.46 Epidermoid Cyst. (A) Sagittal, magniied sonogram shows a sharply deined lesion composed of multiple circular layers caused
by epidermal tissue. (B) Histologic specimen. (Courtesy of Janet Strife, MD, Cincinnati Children’s Hospital.)
FIG. 54.47 Leukemic Iniltration of Testis in 13-Year-Old Male
With B-Cell Leukemia Relapse and an Enlarged Right Testis. Sagittal
image reveals a predominately hypoechoic and enlarged (6.7 mL) right
testis representing diffuse leukemic iniltration. The normal left testis
(not shown) was 1.1 mL in volume.
epidermoids, and cysts. 156,165 here are also nonneoplastic lesions
that resemble benign solid neoplasms, including cystic dysplasia,
adrenal rests, hematomas, and Leydig cell hyperplasia. 166 he
sonographic appearance is quite variable, but characteristically
the epidermoid cyst is hypoechoic, is well circumscribed, and
contains internal echoes or an onion-skin lamellated appearance 167
(Fig. 54.46). Adrenal rests appear in the testes when fetal adrenal
cortical cells migrate coincidentally with the gonadal tissue during
embryologic development. Adrenal rests form tumorlike masses
in response to increased levels of adrenocortical hormones, usually
caused by congenital adrenal hyperplasia or Cushing syndrome.
On sonography, adrenal rests appear as round, variably sized,
hypoechoic, solid intratesticular nodules, usually located near
the mediastinum testis. 166,168,169 hey are usually bilateral intratesticular
nodules that may enlarge or regress over time. 169 he
rests resemble Leydig cell tumors histologically and sonographically,
but the clinical setting of abnormal hormonal levels associated
with hyperfunctioning adrenals usually clariies the
diagnosis. 170
he testes are a well-known sanctuary site for leukemia and
lymphoma (Fig. 54.47). Clinically silent testicular involvement
may be seen in 25% of boys with newly diagnosed acute lymphoblastic
leukemia. he testes may be enlarged and homogeneously
hypoechoic or may contain focal hypoechoic masses. 171,172
Bilateral involvement is most common, and color Doppler low
is almost always increased, with a disorganized vascularity. 173
Neuroblastoma, Wilms tumor, Langerhans cell histiocytosis,
retinoblastoma, rhabdomyosarcoma, and sinus histiocytosis
may metastasize to the testes. 174 he spread may be lymphatic
or hematogenous or by direct extension from contiguous tumor.
he masses are painless and irm, or there may be difuse testicular
enlargement. he sonographic indings in these testicular tumors
are not speciic. he involved testicle is usually enlarged with a
globular or lobulated contour. Both primary and metastatic tumors
may result in focal masses or difuse involvement. he echogenicity
ranges from hypoechoic to hyperechoic, and the parenchyma
may be homogeneous or heterogeneous with areas of decreased
echogenicity, relecting hemorrhage or necrosis or areas of
increased echogenicity relecting calciication. 162,171,173,175,176 At
times, the echogenicity will be normal. 173 Gray-scale abnormalities
may be seen more frequently in the testes of older postpubertal
patients with testicular tumors. his may relect the histologically
diferent tumors afecting diferent age groups.
Color Doppler imaging is helpful in the evaluation of pediatric
testicular tumors. Disorganized hypervascular blood low was
seen in six (86%) of seven patients in a study of pediatric patients
with testicular tumors by Luker and Siegel. 173 Although all the
patients had testicular enlargement, the testicular echotexture
in four (57%) of seven patients was normal; thus color Doppler
was helpful in depicting the tumor in these patients. Hypervascularity
with normal echogenicity may be seen in orchitis;
however, orchitis without epididymitis is uncommon, especially
in prepubertal children, and history helps in distinguishing the
two entities because tumor frequently manifests as an enlarged,
nontender mass. 173 he management of testicular tumors in
childhood has evolved during the last 20 years as a result of a
multicenter retrospective survey that identiied the preoperative
and intraoperative criteria of nonmalignancy and analyzed the
results of conservative management of a testicular mass. Valla 177
reported the indings of the Study Group in Pediatric Urology.
A testicular tumor in children had a 50% chance of being benign,
and ultrasound results were more conclusive than clinical criteria
in limiting the preoperative diagnosis to teratoma, epidermoid
cyst, and, particularly, simple cyst. he group concluded that
treatment selection according to clinical, biologic, radiologic,
and frozen-section indings should allow appropriate decision