Hepatic tumors

Chapter 27 Hepatic tumors



Adrian M. Di Bisceglie, MD, FACP



Key Points



1 Hemangioma of the liver is found in up to 7% of the normal population and is rarely of clinical consequence.

2 Other benign tumors of the liver are rare, including hepatic adenoma, which usually requires surgical resection because of the risks of rupture and the possible development of malignancy.

3 In the presence of cirrhosis, hepatocellular carcinoma (HCC) accounts for approximately 75% of all liver tumors. The most important risk factors for development of HCC are cirrhosis of any cause, hepatitis B virus infection, and hepatitis C virus infection with advanced fibrosis.

4 Although surgical resection offers the best chance of cure in HCC, few patients are suitable candidates for surgery. Liver transplantation is effective in selected patients.

5 Cholangiocarcinoma (CCC) is rising in incidence in the United States, probably in association with chronic liver disease. CCC of the central type is often associated with primary sclerosing cholangitis and has a poor prognosis.


Benign Tumors of the Liver



Hepatic adenoma



image This is a benign proliferation of hepatocytes. It is a rare tumor that occurs largely in female patients. Its incidence has increased since the 1960s, probably related to the introduction and increased use of oral contraceptives.

image Studies have identified genetic abnormalities associated with adenoma, including hepatocyte nuclear factor (HNF)–1α inactivation and β-catenin activation.

image Patients typically present with pain or discomfort in the right upper quadrant, although occasional tumors are found incidentally. Adenomas may rupture, resulting in hemoperitoneum.

image Adenomas are usually single, but may be multiple, rarely with more than five lesions. The size is variable but typically greater than 5 cm in diameter at diagnosis and sometimes massive.

image Hepatic adenomatosis is a rare condition characterized by large numbers of adenomas in the liver with a high rate of recurrence.

image Histologic examination of hepatic adenoma shows benign hepatocytes organized in cords but with no portal triads.

image The presence of a mass in the liver may be confirmed by computed tomography (CT), ultrasonography, or magnetic resonance imaging (MRI). Technetium (99mTc) radioisotope scan may show a defect within the liver. The diagnosis may be confirmed by liver biopsy.

image Treatment includes discontinuing the use of estrogens. Surgical resection is usually advisable, to obtain tissue to confirm the diagnosis and because of the risk of rupture. Liver transplantation may be considered for adenoma found in association with type I glycogen storage disease or hepatic adenomatosis because of the high risk of malignant transformation.


Tumor-like lesions of hepatocytes



1. Focal nodular hyperplasia (FNH) represents an abnormal proliferation of hepatocytes around an abnormal hepatic artery. The artery is usually embedded in a characteristic central stellate scar.
image FNH is usually clinically silent and is typically found incidentally, often at the time of abdominal surgery for another reason.

image In comparison with adenoma, FNH tends to be smaller and carries little risk of rupture. Multiple lesions are found in approximately 20% of patients.

image A hepatic arteriogram may suggest the diagnosis if a tumor can be found surrounding a large hepatic artery.

image The diagnosis may be difficult to make on needle biopsy. Excisional biopsy may be required and is usually curative.

2. Nodular regenerative hyperplasia (NRH) is characterized by the diffuse formation of nodules composed of hepatocytes throughout the liver. The pattern is similar to cirrhosis, except these nodules do not have a surrounding rim of fibrosis.
image NRH is often associated with identifiable systemic diseases such as autoimmune disorders, rheumatoid arthritis (including Felty’s syndrome), and myeloproliferative disorders (see Chapter 22).

image The pathogenesis is unknown but often appears to be related to obliterative venopathy involving portal vein branches.

image The incidence of NRH increases with age and is found most commonly in persons more than 60 years old.

image NRH is often complicated by the development of presinusoidal portal hypertension. Patients may present with splenomegaly and hypersplenism or bleeding esophageal varices.

image No specific therapy is available, but patients may require beta blocker therapy, endoscopic therapy, or rarely, portal decompression to prevent rebleeding from varices. Generally, patients with NRH tolerate variceal bleeding better than those with cirrhosis, presumably because they have relatively well-preserved hepatic synthetic function.

3. Adenomatous hyperplasia (macroregenerative nodule, dysplastic nodule)
image This term is used for regenerative nodules of hepatocytes greater than 1 cm in diameter found in association with cirrhosis or, rarely, submassive hepatic necrosis. Adenomatous hyperplasia represents a form of dysplastic nodule.

image In the context of cirrhosis, adenomatous hyperplasia is strongly associated with the development of HCC.

image No specific therapy is needed. In patients with cirrhosis, the presence of adenomatous hyperplasia should signal the need for intensive surveillance for the development of HCC (see later).

4. Partial nodular transformation: This rare condition is characterized by the presence of nodules of hepatocytes located in the perihilar region and associated with portal hypertension.


Hemangioma



image Hemangiomas of the liver are relatively common, identified in at least 7% of autopsies.

image They are composed of an endothelial lining on a thin fibrous stroma making up cavernous, blood-filled spaces.

image They are usually small; if larger than 10 cm in diameter, they are referred to as giant or cavernous hemangiomas.

image They are usually asymptomatic but, if large enough, may cause some abdominal discomfort. Occasionally, thrombosis within a giant hemangioma may result in consumption of platelets and thrombocytopenia, particularly in children (Kasabach–Merritt syndrome). Hemangiomas have been documented to increase in size over time but have no potential to become malignant.

image Hemangiomas usually do not require any specific therapy. They may be resected if they are associated with significant symptoms. Percutaneous needle biopsy should be avoided because of the risk of bleeding.


Benign hepatic tumors of cholangiocellular origin



1. Bile duct adenoma: This is typically a solitary subcapsular tumor, composed of a proliferation of small, round, normal-appearing bile ducts with cuboidal epithelium.

2. Biliary microhamartoma (von Meyenburg’s complex): This is part of the spectrum of adult polycystic disease but may also be found together with polycystic disease (adult or childhood type), congenital hepatic fibrosis, or Caroli’s disease (see Chapters 23, 28, and 33).

3. Biliary cystadenoma: This multiloculated cyst is analogous to mucinous cystadenomas of the pancreas. It has significant potential for development of malignancy.

4. Biliary papillomatosis: This rare condition consists of multicentric biliary tract adenomatous polypoid tumors that sometimes develop into adenocarcinoma (analogous to familial adenomatous polyposis).


Benign hepatic tumors of mesenchymal origin


These tumors are listed in Table 27.1.


TABLE 27.1 Benign hepatic tumors of mesenchymal origin

































Tumor Comment
Mesenchymal hamartoma Childhood tumor with a mixture of elements (bile ducts, vessels, and mesenchyma)
Infantile hemangioendothelioma Tumor of infancy; may be complicated by thrombocytopenia, high-output heart failure; may require resection or ablation
Lipoma Collection of lipocytes; distinct from focal fatty change within hepatocytes
Lymphangiomatosis Masses of prominent, dilated lymphatic channels
Angiomyolipoma Distinct radiographic appearance
Leiomyoma Extremely rare
Fibroma Solid fibrous tumor of the liver
Inflammatory pseudotumor Chronic inflammation and fibrosis; may cause pain, fever
Myxoma Myxomatous connective tissue


Malignant Tumors of the Liver



Metastatic disease


The liver is a common site of metastasis. Metastases are by far the most common form of hepatic malignancy. The most frequent sites of origin for hepatic metastases are lung, breast, and gastrointestinal and genitourinary tracts.



Hepatocellular carcinoma


HCC is a malignant tumor of hepatocytes.

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Jun 4, 2016 | Posted by in GASTROENTEROLOGY | Comments Off on Hepatic tumors

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