Diagnostic ultrasound ( PDFDrive )

822 PART III Small Parts, Carotid Artery, and Peripheral Vessel Sonography
the adjacent sot tissues of the inguinal canal. 15 Distally, it may
be visualized within the scrotum when a hydrocele is present or
with the use of color low Doppler sonography.
INTRATESTICULAR SCROTAL MASSES
When a scrotal mass is palpated, the concern is for the presence
of a testicular neoplasm. With sonographic examination, intrascrotal
masses can be detected with a sensitivity of nearly 100%. 16
Delineation between intratesticular and extratesticular processes
is 98% to 100% accurate. 16-19 In general, intratesticular masses
should be considered malignant. 19,20 If the mass is extratesticular
and cystic, then this process is almost certainly benign, with the
general accepted prevalence of malignancy of extratesticular
lesions being 3% to 6%. 19,21-24
Testicular neoplasms account for 1% to 2% of all malignant
neoplasms in men and represent the most common nonhematologic
malignancy in men in the 15- to 49-year-old age group. 25-27
Most (65%-94%) patients with testicular neoplasms present with
painless unilateral testicular masses or difuse testicular enlargement,
and 4% to 14% present with symptoms of metastatic
disease. 3,28,29 Approximately 10% to 15% of patients will present
with pain and initially may be misdiagnosed as having
epididymo-orchitis. 30
Testicular tumors are subdivided into two major categories:
germ cell and stromal tumors, with germ cell tumors accounting
for 90% to 95% of all testicular tumors. Germ cell tumors arise
from primitive germ cells and are further divided into seminoma
and nonseminomatous germ cell tumors (NSGCTs). hese
tumors are uniformly malignant. Non–germ cell (sex cord–
stromal) primary tumors of the testis derive from the sex cords
(Sertoli cells) and the stroma (Leydig cells) and are malignant
in approximately 10% of cases. 3,29 Nonprimary tumors include
lymphoma, leukemia, and metastases and can present as intratesticular
masses. Color Doppler imaging has limited ability to
distinguish between malignant and benign solid intratesticular
masses. 31
Malignant Tumors
Germ Cell Tumors
Intratubular germ cell neoplasia is believed to be the precursor
of most germ cell tumors and is the equivalent of carcinoma in
situ. It is thought that these abnormal cells develop along a
unipotential line and form seminoma, or develop along a totipotential
line and form nonseminomatous tumors. 33,34 Seminomas
are radiosensitive tumors, whereas NSGCTs respond better to
surgery and chemotherapy. 27
Approximately 95% of primary testicular neoplasms larger
than 1.6 cm in diameter show increased vascularity on color
low Doppler examination. However, color Doppler indings do
not appear to be important in the evaluation of adult testicular
tumors. 35 Color low may help to identify tumors that are relatively
isoechoic with testicular parenchyma, 36 but focal or difuse
inlammatory lesions cannot be distinguished from neoplasms
on the basis of color low Doppler or spectral Doppler indings.
Nonpalpable testicular tumors have also been detected with
Pathologic Classiication of Testicular
Tumors 32
GERM CELL TUMORS
Seminoma
Classic
Spermatocytic
Nonseminomatous germ cell tumors
Mixed malignant germ cell
Embryonal cell carcinoma
Yolk sac tumor (endodermal sinus tumor)
Teratoma
Choriocarcinoma
Placental site trophoblastic tumor
Trophoblastic tumor, unspeciied
Regressed tumor
STROMAL TUMORS
Leydig cell (interstitial)
Sertoli cell
Granulosa cell
Mixed undifferentiated sex cord
MIXED GERM CELL–STROMAL TUMORS
Gonadoblastoma
Germ cell–stromal–sex cord, unclassiied
METASTATIC NEOPLASMS
Lymphoma
Leukemia
Myeloma
Carcinoma
OTHER a
Adrenal rests
Epidermoid cyst
Malacoplakia
Carcinoid tumor
Mesenchymal tumor
Granulomatous disease
a Rare tumors and nonneoplastic tumorous conditions.
Modiied from Moch H, Cubilla AL, Humphrey PA, et al. The 2016
WHO classiication of tumours of the urinary system and male genital
organs-Part A: renal, penile, and testicular tumors. Eur Urol.
2016:70(10):93-105. 32
sonography in patients presenting for scrotal discomfort or
infertility. 37-40 Incidentally discovered nonpalpable lesions are
oten benign, but 20% to 30% are malignant. 38,39,41
Tumor markers have a role in diagnosis, staging, prognosis,
and follow-up of a number of germ cell tumors, with three markers
having clinical use: α-fetoprotein, human chorionic gonadotropin,
and, less so, lactate dehydrogenase. α-Fetoprotein is
produced by the fetal liver, gastrointestinal tract, and yolk sac
and is elevated in yolk sac tumors or mixed germ cell tumors
containing yolk sac elements. Human chorionic gonadotropin
is a glycoprotein produced by syncytiotrophoblasts of the developing
placenta. It is elevated in tumors containing syncytiotrophoblasts,
including choriocarcinoma and seminoma. Lactate
dehydrogenase, although not speciic, correlates with bulk of
disease and is used in staging. 20