Tumors of the Liver



Tumors of the Liver

Benign Tumors

• Cavernous Hemangioma

o Most common tumor of the liver overall

o Looks like reddish-purple subcapsular nodules

o It is good that radiologists can easily detect these on CAT scans, because no treatment is required. An unnecessary needle aspiration may cause hemorrhage because the liver is so vascular.

Slide: Gross picture of a hemangioma with dark circumscribed lesions and dilated blood vessels

• Focal Nodular Hyperplasia – probably not a true neoplasm

o Commonly found in young to middle aged patients; more women than men

o May be associated with oral contraceptives

o Presents as a single large nodule where a central stellate vascularized scar contains proliferating bile ducts and inflammatory cells.

Slide: Gross picture (Robbins, pg. 886) where the central scar is apparent

Slide: Microscopic view of the tumor with a collagen stain that emphasizes the central scar.

Slide: Proliferating ducts and inflammatory cells are seen at a higher power

• Nodular Regenerative Hyperplasia

o A diffuse lesion with tons of nodules

o Grossly, it looks like cirrhosis, but there is no fibrosis

o Less common than cirrhosis

o It is probably related to focal nodular hyperplasia.

o Portal hypertension may develop with the nodular regenerative hyperplasia because it is diffuse, UNLIKE focal nodular hyperplasia.

o (Gross picture in Robbins, pg. 887 and microscopic slide in Curran, pg 194)

• Adenomas (No bile ducts – just proliferation of hepatocytes)

o Liver Cell Adenomas (a.k.a. hepatocellular adenoma) – a benign, true neoplasm of hepatocytes

▪ Usually presents in young women on oral contraceptives

▪ May spontaneously regress

▪ Characterized by yellow-tan nodules with sheets and cords of hepatocyte-like cells. Usually one nodule is seen with no bile ducts. This tumor is hard to differentiate from well-differentiated hepatocellular carcinoma.

▪ NO PORTAL TRACTS ARE PRESENT!!

▪ Caution! This tumor has a tendency to rupture leading to intra-peritoneal hemorrhage that may be massive and life threatening. Therefore, it is usually excised.

Slide: hepatocellular adenoma with a rupture and hemorrhage (Robbins, pg 887)

Slide: High power view – See lots of hepatocytes and it almost looks normal, except there are no portal tracts. (Curran, pg 206)

o Bile Duct Adenoma

o Usually single, small subcapsular aggregates of uniform epithelium lined ducts

Slide: Bile duct adenoma at high power showing benign bile ducts.

Malignant Tumors of the Liver

Primary Carcinoma of the Liver (o.k. Liver cell carcinoma, hepatoma or hepatocellular carcinoma) KNOW NAMES!!

o More common in countries endemic for viral hepatitis (especially Hepatitis B). It is especially common in China, where vertical transmission of hepatitis B frequently occurs. Nearly all of these children have chronic hepatitis, which leads to carcinoma.

o Occurs more in older males and blacks

o α-fetoprotein is a good tumor marker, because it is often made by these tumors.

o Risk factors:

▪ Cirrhosis (almost always precedes this carcinoma)

▪ Hepatitis B (especially if vertically transmitted)

▪ Hepatitis C

▪ Aflatoxins

▪ Anything that causes cirrhosis – i.e. alcohol

▪ Hereditary tyrosinemia – a rare metabolic disease ( 40% develop hepatocellular carcinoma

o Morphology

▪ Unifocal, multifocal or can diffusely involve the entire liver

▪ Green discolorization from bile

▪ Well differentiated and bile secretion is often present (different than cholangiocarcinoma)

▪ Similar to renal cell carcinoma, this cancer likes to invade and travel down veins like the portal vein or the inferior vena cava (even into the right atrium!).

Slide: Grossly, it looks like a green unifocal, large lesion. (Robbins, pg 889)

Slide: Gross picture showing a tumor and nodules with cirrhosis in the background.

Slide: Gross picture of diffuse hepatocellular carcinoma (hard to differentiate from cirrhosis or nodular hyperplasia). The tiny nodules from the cancer are hard to differentiate from cirrhosis.

Slide: Well differentiated hepatocellular carcinoma – microscopic view. Nuclei are atypical and have prominent nucleoli. Sinusoidal pattern with bile present. This is hard to differentiate from hepatocellular adenoma. Consider who the patient is – older male or young female (adenoma). Also, the plates of liver cells are usually thicker in carcinoma than in adenoma. (Curran, pg 206-207)

Slide: Malignant hepatocellular carcinoma with huge black nucleoli. It is anaplastic, so it is hard to tell if it is hepatocellular.

o Fibrolamellar Variant of hepatocellular carcinoma

o Young patients

o No association with HBV or cirrhosis

o Better prognosis

Slide: Cells of this tumor are separated by bands of fibrosis.

Cholangiocarcinoma

o Less common cancer that arises from the bile duct.

o Risk factors: exposure to Thorotrast (radiographic dye no longer used), liver flukes (Clonorchis)

o NO bile secretion

o Mucus secretion may be present

o Has a lot of fibrosis

o More commonly metastasize than hepatocellular carcinoma

Slide: Gross tumor looks white; it is hard and dense from fibrosis. (Robbins, pg 890)

Slide: Tumor appears to have normal ducts, except there is no bile. It is well differentiated, and some areas have more fibrosis than others. (Curran, pg 207)

Slide: Cholangiocarcinoma with a more papillary form and more fibrosis.

o Clinical Aspects of Primary Liver Carcinoma

o Nonspecific GI symptoms, hepatomegaly, jaundice, cirrhosis

o Lab markers

▪ Elevated serum AFP (α-fetoprotein)

▪ Elevated CEA (carcinoembryonic antigen) – less specific; more likely with cholangiocarcinoma

o Dismal prognosis ( death within 6 months due to liver failure and complications from portal hypertension like esophageal variceal bleeding.

o Rare Forms of Primary Liver Cancer

o Hepatoblastoma

▪ Fetal tumor of the liver, so it has immature hepatocytes.

▪ Appears in young children and is fatal within a few years

▪ Consists of fetal epithelial elements that may be admixed with foci of mesenchymal differentiation like cartilage.

Slide: Hepatoblastoma – Embryonic hepatocytes are smaller and are hard to tell that they are hepatocytes. These cells have a clear cytoplasm due to glycogen and lipid in the cytoplasm. Osteoid production is present showing the mesenchymal contribution.

o Angiosarcoma

▪ Very aggressive ( fatal within 1 year

▪ Occurs with exposure to vinyl chloride, arsenic, and thorotrast.

Slide: Angiosarcoma composed of endothelial cells (i.e. blood vessels) – several intertwining blood vessels with atypical nuclei

Metastatic Tumors of the Liver

o Most common malignancy of the liver

o Originate from breast, lung, colon, stomach

o Presents with hepatomegaly, multiple metastatic nodules, jaundice, and abnormal liver function tests (if massive)

Slide: Gross picture with innumerable nodules throughout the liver.

Scribe note: Dr. Oliver then gave a presentation about pathology as a career. If you are interested in pathology, talk to him.

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