Chapter 18: LIVER:BENIGN NEOPLASMS

Question 1

BENIGN NEOPLASMS of the LIVER

Answer 1

Cavernous hemangiomas

Hepatic Adenoma

Question 2

What are the most common benign liver tumors?

Answer 2

Cavernous hemangiomas, blood vessel tumors identical to those occurring elsewhere (see
Chapter 11 ), are the most common benign liver tumors.

Question 3

What is the appearance cavernous hemangiomas?

Answer 3

They appear as discrete red-blue, soft
nodules, usually less than 2 cm in diameter, generally located directly beneath the capsule.

Histologically, the tumor consists of vascular channels in a bed of fibrous connective tissue (
Fig. 18-44 ).

Question 4

What is the chief clinical significance of cavernous hemangiomas?

Answer 4

Their is that they should not be mistaken for metastatic
tumors, and thatblind percutaneous biopsies not be performed on them.

Question 5

Answer 5

FIGURE 18-44 Hemangioma. The photomicrograph shows the vesicular channels
embedded in fibrous stroma

Question 6

What are hepatic adenomas?

Answer 6

Benign neoplasms developing from hepatocytes are called hepatic adenomas or liver cell
adenomas.

Question 7

What gender is hepatic adenomas more common?

Answer 7

Although they may occur in men, hepatic adenomas most frequently occur in young
womenwho haveused oral contraceptives; tumorsgenerally regress if contraceptive use is
terminated.

The incidence of adenoma is approximately 1 in 100,000.

Question 8

Hepatic adenomas have
clinical significance for three reasons:

Answer 8

• (1) when they present as an intrahepatic mass they may be mistaken for the more ominous hepatocellular carcinomas;
• (2) subcapsular adenomas have a tendency to rupture, particularly during pregnancy (under estrogen stimulation), causing lifethreatening intraperitoneal hemorrhage;
• (3) rarely, they may transform into carcinomas, particularly, when the adenoma arises in an individual with glycogen storage disease, and adenomas in which mutations of the β-catenin gene are present.

Question 9

What is the pathogenesis of hepatic adenoma?

Answer 9

Although hormonal stimulation is clearly associated with the development of solitary hepatic
adenoma, the causal events are unknown.

Mutations in the genes encoding the transcription
factor HNF1α andβ-catenin have been identified in 50% and 15% of the hepatic adenomas,
respectively. [72]

Multiple hepatic adenoma (adenomatosis) syndromes can occur in individuals with maturity-onset diabetes of young (MODY3), with HNF1 mutations.

Question 10

What is the appearance of Liver cell adenomas?

Answer 10

• pale,
• yellowtan, and
• frequently bile-stained nodules,
• found anywhere in the hepatic substance but often beneath the capsule ( Fig. 18-45A ).
• They may reach 30 cm in diameter.
• Although they are usually well demarcated, encapsulation might not be present.
• The tumor commonly presents as a solitary lesion, but multiple lesions (adenomatosis) can occur.

Question 11

What is the histological appearance of liver cell adenomas?

Answer 11

composed of sheets and cords of cells that may resemble normal hepatocytes or have some variation in cell and nuclear size ( Fig. 18-45B ).

Abundant glycogen may generate large hepatocytes with a clear cytoplasm.

Steatosis is commonly present. Portal tracts are absent; instead, prominent
solitary arterial vessels and draining veins are distributed through the substance of the tumor.

Question 12

Answer 12

FIGURE 18-45 Liver cell adenoma. A, Resected specimen presenting as a pendulous
mass arising from the liver. B, Microscopic view showing cords of hepatocytes, with an
arterial vascular supply (arrow) and no portal tracts.

Question 13

END

Benign tumors of the liver