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3

Biliary Tree and Gallbladder

Gallbladder Varicosity

When hypoechoic tubular intramural and extramural changes in the gallbladder wall are encountered, the differential diagnosis should include varicosity (Fig. 3.53; see Fig.1.99b, p. 50). It is characteristic of portal hypertension (in prehepatic or posthepatic block). The suspected diagnosis is confirmed by color-flow duplex scanning (Table 3.3). This modality is

also important in preoperative delineation of vascular anomalies. Its application in the differentiation of a benign polypoid mass (perfusion of the stalk in adenomas) from a malignancy is still experimental (Table 3.3). The significance of contrast enhancement in differentiating between benign polypoid masses and malignant tumors is still unknown.

Table 3.3 Color-flow duplex scanning in gallbladder disease

Vascular anomalies in the hepatoduodenal ligament before surgery

Varicosity of the gallbladder wall

Perfusion of the polyp stalk (experimental)

Vascularization of tumors (experimental)

Fig. 3.53 Varicose veins of the gallbladder wall: intraand perimural tubular formations (arrow) are typical.

a Portal venous collaterals in the gallbladder wall.

b Thickened gallbladder wall in portal hypertension, CDS.

General Tumor

Gallbladder

Changes in Size

Wall Changes

General Hypoechogenicity

General Hyperechogenicity

Focal Hypoechogenicity/Hyperechogenicity

General Tumor

Focal Tumor

Intraluminal Changes

Nonvisualized Gallbladder

Adenomyomatosis

Cholesteatosis

Gallbladder Carcinoma

Adenomyomatosis

Adenomyomatosis is a special case of gallbladder cholesteatosis and belongs to the group of hyperplastic cholecystoses. It appears as a hyperechoic pseudotumorous thickening of the wall (generalized or focal), originating from hypertrophied Rokitansky–Aschoff sinuses. This disorder is characterized by coexistent cholesterol deposits (with their typical “comet tail” artifacts) and cystic intramural inclusions (Fig. 3.54; see Fig. 3.63, Table 3.4).

Fig. 3.54 Adenomyomatosis: typical “comet-tail” pattern (arrow) caused by cholesterol deposits.

156

Table 3.4 Comet-tail artifacts in gallbladder ultrasound

 

 

 

 

Emphysematous

Cholesteatosis

Adenomyomatosis

Microliths

Pneumobilia

 

cholecystitis

 

 

 

 

Size

Large

Normal

Normal or smaller

Normal

Normal

Shape

Round

Normal

Hourglass furrows

Normal

Normal

Lumen

Sludge

Normal

Constricted

Floating (calculi

Normal

 

 

 

 

< 5 mm)

 

Wall

Hypoechoic wall thick-

Often normal or

Hyperechoic, thick-

Normal

Normal

 

ening

slightly thickened

ened, cystic inclusions

 

 

Comet-tail artifacts

Intramural or intralu-

Intramural, partly few,

Localized, intramural

Floating in the lumen

Position-dependent

 

minal gas collections

partly di use

or di use

 

gas collections at the

 

 

 

 

 

anterior wall

Cholesteatosis

Adenomyomatosis

should be

differentiated

 

from cholesteatosis

(strawberry

gallbladder),

 

which is also characterized by numerous

 

comet-tail artifacts but mostly without the

 

wall thickening (Fig. 3.55a,b).

 

 

Fig. 3.55

 

 

 

a Cholesteatosis (“strawberry gallbladder”): classic intra-

 

mural hyperechoic “spotted” echoes with comet-tail arti-

 

facts.

 

 

 

b Twinkling artifact in the region of comet-tail artifacts.

 

Gallbladder Carcinoma

 

General adenomyomatosis should also be dif-

Gallbladder carcinoma lacks the Rokitan-

ferentiated from diffuse infiltrating gallbladder

sky–Aschoff sinuses and intramural comet-tail

carcinoma, although the latter completely de-

artifacts.

stroys the regular wall layering (see Fig. 3.64).

 

Focal Tumor

Gallbladder

 

 

 

Changes in Size

 

Cholesterol Pseudopolyps

 

 

 

 

 

Wall Changes

 

Adenomas and Papillomas

 

 

 

 

 

 

 

 

 

General Hypoechogenicity

 

Adenomyomatosis

 

 

 

 

General Hyperechogenicity

 

Gallbladder Carcinoma

 

 

 

 

Focal Hypoechogenicity/Hyperechogenicity

 

 

 

 

 

 

Metastasis

 

 

 

 

General Tumor

 

 

 

 

 

 

 

 

 

 

 

Focal Tumor

 

 

 

 

 

 

Intraluminal Changes

 

 

 

 

 

 

 

 

 

 

 

 

Nonvisualized Gallbladder

 

 

 

 

 

 

 

 

In order of frequency, focal changes in the gallbladder wall are mural polypoid lesions, partial wall thickening, and infiltrating lesions.

3

Wall Changes

157

3

Biliary Tree and Gallbladder

Cholesterol Pseudopolyps

Cholesterol pseudopolyps are the most frequently demonstrated. They are hyperplastic polypoid neoplasms, usually hyperechoic, smoothly contoured, round or ovoid. Sometimes they are visualized as small hyperplastic (often hyperechoic) tumors, pendulant from the gallbladder wall, that may display a short

stalk (hypoechoic lobulation is rather rare). Usually, their size is less than 6 mm and they are found in multiples (Figs. 3.56, 3.57, 3.58). The gallbladder wall always appears normal. Cholesterol polyps measuring more than 1 cm in diameter are the exception and therefore should undergo surgery. The detection of cho-

lesterol pseudopolyps is highly dependent on the quality of the equipment. The most recent studies show that cholesterol pseudopolyps 1 mm in size can be detected (in up to 10% of all cases examined).10

Fig. 3.56 Cholesterol pseudopolyp: characteristic visualization of a hyperechoic 5 mm cholesterol pseudopolyp at the floor of the gallbladder.

Fig. 3.57 Cholesterol pseudopolyps. Multiple small sessile hyperechoic polyps of 3–5 mm at the gallbladder wall (some with longer stalks).

Fig. 3.58 Characteristic sonographic morphology of five hyperechoic cholesterol pseudopolyps of less than 5 mm diameter.

Adenomasand Papillomas

Adenomas. Compared with the more common

size. Because of the known adenoma–carci-

cholesterol pseudopolyps (>1% of the popula-

noma sequence they have to undergo surgery.

tion) adenomas are infrequent findings (Figs.

 

3.59, 3.60, 3.61). Usually, they are hypoechoic

Papillomas. The differentiation of adenomas

sessile structures resting on the intraluminal

from papillomas relies on the fact that papillo-

wall and are frequently found in the neck of

mas tend to be pedunculated, displaying a lo-

the gallbladder. They usually exceed 10 mm in

bulated surface. Papillomas tend to be located

at the fundus and usually are hypoechoic (Fig. 3.62, Table 3.5). All polyps are easily differentiated from calculi by their sessile growth, although sometimes viscous pseudopolypoid sludge may mimic a polyp. If a papilloma is suspected, surgical treatment is indicated.

Fig. 3.59 Pedunculated adenoma of about 2 cm (con-

Fig. 3.60 Sessile adenoma: sessile adenoma of about 2 cm

Fig. 3.61 Flat adenoma (14 mm; histology) of the gallblad-

firmed histologically) in the body of the gallbladder.

diameter in the body of the gallbladder.

der. CDS shows intratumoral vessels. Intact wall. Young

 

 

female, incidental finding.

Fig. 3.62 Papilloma.

a Lobulated papilloma of the body of the gallbladder with a diameter of about 1.2 cm.

b

and c Papilloma (adenomatous polyp): lobulated papilloma of the body of the gallbladder.

b Gray-scale image.

c CDS with intratumoral branching vessels.

158

Table 3.5 Focal intraluminal polypoid wall changes

 

 

 

 

Cholesterol pseudopolyp

Adenoma

Papilloma

Carcinoma

Size

Often 2–6 mm and multiple,

Solitary, often > 1 cm

Solitary, > 7 mm

Solitary, > 1–2 cm

 

rarely > 8 mm

 

 

 

Shape

Mostly round, sometimes bi-

Sessile, polypoid, or superficial

Lobulated

Polypoid

 

zarre, short stalk

 

 

 

Echogenicity

Mostly rather hyperechoic

Usually hyperechoic

Rather more hypoechoic

Hypoechoic, inhomogeneous

Wall

Regular

Normal

Normal

Infiltrated

Location

Varying

Rather more in the neck

Rather more in the fundus

Varying

Adenomyomatosis

A good example of partial wall thickening is adenomyomatosis, which may also present as a hyperechoic focal lesion (Fig. 3.63a). Combined with the focal cystic inclusions and the classic comet-tail artifacts, the focal hypertrophied Aschoff–Rokitansky sinuses will round out the characteristic image in sonographic morphology. In focal adenomyomatosis the gallbladder may undergo segmental constriction (hourglass gallbladder) (Fig. 3.63b).

Fig. 3.63 Adenomyomatosis (focal and segmental).

b “Hourglass gallbladder” in adenomyomatosis. In seg-

a Typical adenomyomatosis of the fundus (“fundus ad-

mental adenomyomatosis the gallbladder displays seg-

enoma”): hyperechoic wall thickening with hypoechoic

mental constriction at the body.

inclusions (here no comet-tail artifacts).

 

Gallbladder Carcinoma

Every polypoid mass of irregular shape within the lumen of the gallbladder as well as every infiltrating lesion with destruction of the normal wall should be highly suspicious for gallbladder carcinoma. In the early stages (still manageable by surgery), gallbladder carcinoma is clinically quiescent and will typically present in two manifestations: polypoid carcinoma, mostly filling the lumen; or primarily diffuse infiltrating carcinoma, with destruction of the

normal texture of the gallbladder wall as well as early invasion of the surrounding tissue (Fig. 3.64). The delineation between the mostly hypoechoic infiltrates and the hepatic parenchyma may be ill defined (Fig. 3.64c,d). Local lymph node metastasis takes place at an early stage. Histologically, it is a scirrhous adenocarcinoma. Gallstones and chronic cholecystitis play an important role in the carcinogenesis: 2–3% of people with gallstones will develop a

carcinoma of the gallbladder. Most tumors appear hypovascular in color-flow duplex scanning, but a chaotic vascular pattern can be detected in suspected gallbladder carcinoma. Contrast-enhanced ultrasonography (CEUS) is more useful than color-flow duplex scanning and can demonstrate the extent of the tumor with greater precision (Fig. 3.64e).11

Fig. 3.64 Gallbladder carcinoma.

b Carcinoma of the fundus: hypoechoic adenocarcinoma

c Polypoid infiltrating carcinoma of the body: infiltrating

a Carcinoma of about 3 cm—with the appearance of a

with segmental infiltration of the fundus and body of the

diffusely from the body of the gallbladder into the liver

large polyp—in the body of the gallbladder (FNB).

gallbladder.

(arrows); ill-defined delineation between wall and liver

 

 

parenchyma.

3

Wall Changes

159

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