Diagnostic ultrasound ( PDFDrive )

824 PART III Small Parts, Carotid Artery, and Peripheral Vessel Sonography
A B C
D
E
F
G H I
FIG. 22.5 Seminoma: Spectrum of Appearances. Longitudinal scans. (A) and (B) Subtle hypoechoic seminoma (arrows) with increased low.
(C) Typical homogeneous hypoechoic seminoma. (D) Two small foci of seminoma. (E) Slightly heterogeneous seminoma. (F) Seminoma associated
with microlithiasis and coarser calciications. (G) Seminoma occupying most of testis. Typical homogeneous hypoechoic sonographic appearance.
(H) Gross specimen of seminoma in G. (I) Necrotic seminoma replacing testicle. See also Video 22.1.
have a higher metastatic rate, approximately 20%, than their
ovarian counterpart. 52 Teratomas in their pure form are rare in
adults, although teratomatous elements occur in approximately
half of all adult cases of mixed germ cell tumor (Fig. 22.6B).
Both mature and immature teratomas are generally associated
with normal tumor markers, although elevated levels of
α-fetoprotein or human chorionic gonadotropin may be found. 47
Sonographically, the teratoma is usually a well-deined, markedly
heterogeneous mass containing cystic and solid areas of various
sizes and appears similar to other NSGCTs. Dense echogenic
foci causing acoustic shadowing are common, resulting from
focal calciication, cartilage, immature bone, ibrosis, and noncalciic
scarring (Fig. 22.6E). 44
Choriocarcinoma accounts for less than 1% of malignant
primary testicular tumors in its pure form but occurs in 8% of
mixed germ cell tumors. 20,43,48,50 he peak incidence is in the
second and third decades. hese tumors are highly malignant
and metastasize early by hematogenous and lymphatic routes.
he primary tumor and metastases are oten hemorrhagic, and
patients may have symptoms resulting from hemorrhagic
metastases, including hemoptysis, hematemesis, and central
nervous system–related symptoms. Focal necrosis of the primary
tumor secondary to hemorrhage is an almost invariable feature,
and calciication may be present, giving a sonographic appearance
similar to the other NSGCTs (Fig. 22.6F). he levels of human
chorionic gonadotropin are elevated and cause gynecomastia in
10% of cases. 20,53 Choriocarcinoma has the worst prognosis of
any of the germ cell tumors. 50
Regressed Germ Cell Tumor. Sonography is an important
diagnostic tool for patients who present with widespread metastatic
testicular carcinoma (Fig. 22.7) even though the primary
tumor has involuted (Fig. 22.8); ultrasound is an important
component in the search for a primary testicular neoplasm.
Mediastinal and central nervous system extragonadal tumors
can oten present as primary lesions, although retroperitoneal
germ cell tumors are more likely to have a testicular origin. 54,55
he primary testicular tumor may regress, despite widespread
advancing metastatic disease, resulting in an echogenic ibrous
and possibly calciic scar. Regression may be caused by the high
metabolic rate of the tumor and vascular compromise from the