1. 73Focal Decreased-Attenuation
Masses in the Liver

2. CLINICAL IMAGAGING
AN ATLAS OF DIFFERENTIAL DAIGNOSIS
EISENBERG
DR. Muhammad Bin Zulfiqar
PGR-FCPS III SIMS/SHL

3. • Fig GI 73-1 Simple hepatic cyst. A 20-cm fluid-filled
mass in the right lobe of the liver displaces the
abdominal contents and compresses the inferior vena
cava. After aspiration and the instillation of alcohol,
there was virtual ablation of the cyst.114

4. • Fig GI 73-2 Echinococcal cyst. Multiple large
cysts filling a massively enlarged liver.

5. • Fig GI 73-3 Polycystic liver disease.
Innumerable lucent lesions of various sizes in
a markedly enlarged liver. The patient also had
severe polycystic kidney disease.

6. • Fig GI 73-4 Caroli's disease. (A) CT scan shows
fluid-filled cystic masses in the liver. (B)
Cholangiogram shows the characteristic
dilatation of intrahepatic ducts.

7. • Fig GI 73-5 Choledochal cyst. (A) Contrast CT
shows a cystic mass (C) that is well demarcated
due to the dilation of the distal portion of the
common bile duct. (B) Coronal oblique
reformatted image shows fusiform dilatation of
the common bile duct (arrow). Note also the
dilatation of the intrahepatic biliary tree
(arrowhead).115

8. • Fig GI 73-6 Hepatic abscess. (A) Unenhanced scan shows a
single low-density lesion with poorly defined margins at the
periphery of the liver. (B) After infusion of contrast
material, there is rim enhancement with the margins of the
abscess seen as a white line (arrows) of higher density than
the surrounding normal liver. (C) CT scan in another patient
shows a large collection of gas in a pyogenic abscess in the
lateral aspect of the right lobe of the liver.116

9. Fig GI 73-7 Pyogenic abscess. Large mass (A) in the right lobe of
the liver that contains low-attenuation areas reflecting early
liquefaction.117

10. • Fig GI 73-8 Amebic abscess. Well-
circumscribed, fluid-attenuation mass
(consistent with a simple cyst) in the posterior
portion of the right lobe of the liver.102

11. • Fig GI 73-9 Fungal abscesses. Numerous low-
density lesions in a massively enlarged liver
representing multiple abscesses containing
Candida albicans.98

12. • Fig GI 73-10 Hydatid disease. (A) Unilocular cyst of water
attenuation with a ringlike pattern of calcification. (B) Multiple
daughter cysts in their typical peripheral location within the mother
cyst (arrows). There is partial calcification of the pericyst. (C) Dense
circular area of increased attenuation within the cyst represents
detached and collapsed parasitic membranes (arrows).118

13. • Fig GI 73-11 Echinococcal multilocularis. (A)
Unenhanced and (B) contrast-enhanced scans
demonstrate a large, irregular,
hypoattenuating lesion with dense punctuate
calcifications, which are more clearly seen on
the unenhanced image. Note the poor
enhancement of the lesion.119

14. • Fig GI 73-12 Schistosomiasis. Characteristic
pericapsular and periportal calcifications,
which give the liver a tortoise shell
appearance.119

15. • Fig GI 73-13 Tuberculosis. Multiple low-
attenuation areas of varying size in the liver
and spleen. The imaging findings are not
specific, and thus biopsy is required whenever
this disease is suspected.119

16. • Fig GI 73-14 Fascioliasis. (A, B) Contrast scans
show clustered small low-attenuating lesions
with peripheral enhancement in the
subcapsular area of the right hepatic lobe.
Note the characteristic crooked tract-like
lesion (burrow tract) in B (arrows).120

17. • Fig GI 73-15 Cavernous hemangioma. (A) Initial scan after a
bolus injection of contrast material demonstrates a large
low-density lesion in the posterior segment of the right
lobe of the liver.121(B and C) Delayed scans show
progressive enhancement of the lesion until it becomes
nearly isodense with normal hepatic parenchyma.

18. • Fig GI 73-16 Adenoma. Large low-density mass
in the liver. Note the area of higher density
(arrows), which represents a blood clot, along
the posterior aspect of the lesion.

19. • Fig GI 73-17 Focal nodular hyperplasia.
Noncontrast scan shows an area of low
attenuation (arrow) that is indistinguishable from
a primary or secondary hepatic neoplasm. The
lesion became isodense after the administration
of contrast material.122

20. • Fig GI 73-18 Angiomyolipoma. Well-defined
hepatic mass (arrow) with the attenuation of
fat.123

21. • Fig GI 73-19 Infantile hepatic
hemangioendothelioma. Multiple, rounded,
hypodense masses throughout the liver. On a
delayed postcontrast scan, all of the lesions
became isodense to the surrounding liver.124

22. • Fig GI 73-20 Primary hepatocellular carcinoma.
(A) Huge mass with an attenuation value slightly
less than that of normal liver. The black arrows
point to the hematoma (H)-normal liver interface.
Of incidental note is a pancreatic pseudocyst
(white arrow) in the lesser sac between the
stomach (S) and the pancreas. (B) On a slightly
lower scan, there is absence of the fat plane
surrounding the head of the pancreas (P),
indicating invasion of the pancreas by the tumor.

23. • Fig GI 73-21 Primary hepatocellular
carcinoma. Multiple low-attenuation masses
in the liver.

24. • Fig GI 73-22 Fibrolamellar carcinoma. Contrast-
enhanced scan shows a solitary lobulated, low-
attenuation mass in the lateral segment of the
left lobe with punctate calcification and central
stellate scar. Note the retroperitoneal
metastasis.104

25. • Fig GI 73-23 Cholangiocarcinoma. Large,
lobulated mass containing multiple, large,
chunky, dense areas of calcification. Note the
central areas of decreased attenuation
corresponding to fibrosis.105

26. • Fig GI 73-24 Biliary cystadenoma. Nonenhanced
scan shows a well-defined, ovoid, low-
attenuation liver mass with multiple internal
septations. Multiple calcifications (arrows) are
seen along the wall and internal septa.96

27. • Fig GI 73-25 Angiosarcoma. Contrast-
enhanced scan shows multiple low-
attenuation lesions in a patient with previous
exposure to Thorotrast.125

28. • Fig GI 73-26 Metastases. Multiple, low-density
metastases with high-density centers.

29. • Fig GI 73-27 Metastases. Several large, low-
density lesions filling much of the liver.
Although these lesions simulate benign cysts,
their walls are somewhat shaggy and irregular.

30. • Fig GI 73-28 Kaposi's sarcoma. Multiple, ill-
defined peripheral portal liver nodules
(arrows) in a patient with disseminated AIDS-
related disease. Some of the nodules show
hypoattenuation, whereas others show
enhancement.123

31. • Fig GI 73-29 Lymphoma. Multiple nodules are
scattered throughout the liver.126

32. • Fig GI 73-30 Subcapsular hematoma. Well-
circumscribed elliptical area of low-
attenuation density (arrows) in the periphery
of the right lobe of the liver. The patient had
sustained blunt trauma to the upper abdomen
2 weeks previously.

33. • Fig GI 73-31 Intrahepatic hematoma. The
patient had sustained a gunshot wound of the
liver that was not appreciated at the time of
laparotomy. (A) CT scan shows the bullet
fragment (arrowhead) in a mixed low- and
high-density collection. The high-density area
(arrow) represents clotted blood. (B) One
week later, the hematoma is larger and of
lower density.89

34. Fig GI 73-32 Hepatic laceration. CT scan after blunt trauma shows
an irregular low-density plane (arrows) passing through the right
lobe of the liver.89

35. Fig GI 73-33 Biloma. Multiple intrahepatic and extrahepatic low-
attenuation lesions after traumatic rupture of the biliary tree and
bile peritonitis.

36. • Fig GI 73-34 Radiation injury. Well-demarcated
region of low attenuation corresponding to
the treatment port (arrowheads).127

37. • Fig GI 73-35 Intrahepatic extension of
pancreatic pseudocyst. The area of decreased
attenuation in the region of the falciform
ligament (white arrow) is seen in association
with a pseudocyst in the body of the pancreas
(black arrow).128

38. • Fig GI 73-36 Focal fatty infiltration. The absence of a
mass effect is seen both by the lack of contour
abnormality and by the unaffected course of a portal
vein branch through the area of focal fatty infiltration
(arrows). Note that the margins of the lesion are poorly
defined in this patient.108

39. • Fig GI 73-37 Hepatic infarction. Well-demarcated,
wedge-shaped non-enhancing lesion in the posterior
right hepatic lobe with peripheral low-attenuation
components (straight arrows). Peripheral low-
attenuation regions (curved arrows) could represent
focal accumulations of bile and necrotic liver. Note the
presence of ascites.129

40. Fig GI 73-38 Choledochal cyst. Contrast-enhanced scan shows
dilatation of intrahepatic bile ducts simulating multiple cystic
masses.130

41. • Fig GI 73-39 Sarcoidosis. Multiple irregular
nodules of variable size.131

42. • Fig GI 73-40 Amyloidosis. Contrast-enhanced scan
shows low-attenuation area in the right lobe.
Note that nondisplaced portal and hepatic vessels
course through the low-attenuation mass,
suggesting an infiltrative rather than neoplastic
etiology.132