Diagnostic ultrasound ( PDFDrive )

348 PART II Abdominal and Pelvic Sonography
FIG. 9.55 Morphologic Growth Patterns of Renal Transitional Cell Carcinoma.
the sixth and seventh decades. hey occur most frequently at
the trigone and along the lateral and posterior walls of the bladder.
Approximately 70% of bladder cancers are supericial; the remaining
30% are invasive. Patients typically present with hematuria,
although they may also complain of frequency, dysuria, and
suprapubic pain. Sonographic detection of polypoid bladder
tumors is excellent (≥95%). 191 he appearance is that of a
nonmobile focal mass or of urothelial thickening (Fig. 9.57, Video
9.3). Ultrasound appearances are nonspeciic, however, and the
diferential diagnosis is extensive, including cystitis, wall thickening
caused by bladder outlet obstruction, postradiation/
postoperative change, adherent blood clot, invasive prostate
carcinoma, lymphoma, metastasis, endometriosis, and neuroibromatosis.
Some papillary bladder tumors may also calcify.
Cystoscopy and biopsy are necessary for diagnosis. Both transvaginal
and transrectal ultrasound may also be used to assess a
bladder wall mass if suprapubic visualization is compromised.
Transitional cell (and squamous cell) carcinomas may also
arise within urinary bladder diverticula. Many diverticula have
narrow necks, making them inaccessible for cystoscopic examination,
so imaging plays an important role in the detection of these
tumors. he periureteric and posterolateral wall locations of most
bladder diverticula allow for adequate sonographic visualization. 192
At ultrasound, diverticular tumors are moderately echogenic,
nonshadowing masses. Although ultrasound is good for tumor
detection, staging is still best performed clinically in combination
with CT or MRI. 193
Squamous Cell Carcinoma
Squamous cell carcinoma (SCC) is rare but is the second most
common malignant urothelial tumor ater TCC. SCC accounts
for 6% to 15% of renal pelvic tumors and 5% to 8% of all bladder
tumors. 194,195 Chronic infection, irritation, and stones lead to
squamous metaplasia and leukoplakia of the urothelium.
Leukoplakia is thought to be premalignant. SCC tends to be a
solid, lat, iniltrating lesion with extensive ulceration. Distant
metastases are usually present at diagnosis. As with other iniltrating
renal lesions, renal SCC appears at sonography as a difusely
enlarged kidney that has maintained its reniform shape. Normal
renal echotexture is destroyed, and oten a stone (47%-58%) 194
will be present. It thus may be impossible to diferentiate renal
SCC from XGP. Oten, perinephric tumor extension and metastases
are present. Ureteral SCC is rare; hydronephroureterectasis
proximal to the tumor mass will be apparent. Occasionally, the
lesion is seen as a poorly deined, irregular, solid mass. Associated
stones are oten present. Bladder SCCs tend to be large, solid,
and iniltrating. SCCs may also arise within bladder diverticula. 192
Ultrasound may be an efective modality for detecting pedunculated
bladder SCC, but CT or MRI are more appropriate
modalities for detecting perivesical invasion, regional adenopathy,
and distant metastases.
Adenocarcinoma
Adenocarcinoma of the renal pelvis, ureter, and bladder is rare.
Almost all patients with adenocarcinoma of the renal pelvis have
a history of chronic UTI, 196 and two-thirds have a stone, typically
a staghorn calculus. Clinicians must be careful to diferentiate
adenocarcinoma of the bladder from adenocarcinoma of the
rectum, uterus, or prostate that has invaded the bladder. he
prognosis is poor. At sonography, a renal pelvic, ureteric, or
bladder mass is seen, occasionally with calciication. An associated
stone is oten present.
Oncocytoma
Oncocytes are large, epithelial cells. he characteristic granular
eosinophilic cytoplasm in these cells results from extensive
cytoplasmic mitochondria. Oncocytomas may occur in the
parathyroid glands, thyroid, adrenal glands, salivary glands, and