Diagnostic ultrasound ( PDFDrive )

350 PART II Abdominal and Pelvic Sonography
A B C
D
E
F
G H I
FIG. 9.57 Bladder Masses With Many Origins: Imaging Spectrum. (A) Multifocal polypoid urothelial transitional cell carcinoma (TCC). (B) Invasive
TCC involving the perivesical fat (arrow). (C) Benign prostatic hypertrophy simulating a large invasive bladder wall mass. (D) Diffuse TCC on a transvaginal
sagittal image; Foley catheter is in place. (E) Diffuse invasive TCC on suprapubic scan. (F) Interstitial cystitis closely simulates diffuse tumor.
(G) Endometrioma appearing as a solid mass within posterior bladder wall on a transvaginal sagittal image. Note uterus posterior to bladder mass.
(H) Pheochromocytoma presenting as a vascular polypoid bladder mass at color Doppler transvaginal evaluation. (I) Dependent bladder clot posterior
to Foley catheter balloon simulates a bladder mass. Intraluminal gas along bladder dome induces “dirty shadowing.” See also Video 9.3.
kidneys. Oncocytomas account for 3% to 7% of all renal
tumors. 197,198 hey occur more oten in men (1.7 : 1), with a peak
incidence in the sixth and seventh decades. 199 Most patients are
asymptomatic. 197 Oncocytomas vary in size and may be multicentric
(5%-10%) or bilateral (3%). Bilateral tumors are seen
particularly in hereditary syndromes (Birt-Hogg-Dubé, hereditary
oncocytosis). 198,200 Hemorrhage and calciication are
uncommon. hese tumors histologically may have a benign or
a more malignant appearance. Diferentiation between oncocytomas
and chromophobe RCCs may be diicult, 201 and hybrid
lesions consisting of both oncocytic and chromophobe RCC
elements have been reported (see Fig. 9.51).
Not surprisingly, oncocytoma and RCC cannot be diferentiated
by imaging. Davidson et al. 202 demonstrated that CT homogeneity
and a central stellate “scar” are poor predictors in diferentiating
oncocytomas from RCCs. In earlier surgical series, oncocytomas
represented about 5% of all tumors originally diagnosed as RCC
on imaging. 203 A higher percentage of benign oncocytomas will
likely be documented in future series of smaller, incidental lesions
sampled before nephron-sparing procedures.
here is no distinctive ultrasound appearance of oncocytomas.
hese lesions may be homogeneous or heterogeneous with a
distinct or poorly demarcated wall. 204 A central scar, central
necrosis, or calciication may be seen, although these features