Liver (Including Intrahepatic Bile Ducts) 14
(Sarcomas and tumors metastatic to the liver are not included.)
14
SUMMARY OF CHANGES
• The T categories in this edition have been redefined and simplified.
• All solitary tumors without vascular invasion, regardless of size, are classified as T1 because of similar prognosis.
• All solitary tumors with vascular invasion (again regardless of size) are combined with multiple tumors £5cm and classified as T2 because of similar prognosis.
• Multiple tumors >5cm and tumors with evidence of major vascular invasion are combined and classified as T3 because of similarly poor prognosis.
• Tumor(s) with direct invasion of adjacent organs other than the gallbladder or with perforation of visceral peritoneum are classified separately as T4.
• The separate subcategory for multiple bilobar tumors has been eliminated because of a lack of distinct prognostic value.
• T3 N0 tumors and tumors with lymph node involvement are combined into Stage III because of similar prognosis.
• Stage IV defines metastatic disease only. The subcategories IVA and IVB have been eliminated.
C22.0 Liver C22.1 Intrahepatic bile duct
INTRODUCTION
Primary malignancies of the liver include tumors arising from the hepatocytes (hepatocellular carcinoma), intrahepatic bile ducts (intrahepatic cholangiocar- cinoma and cystadenocarcinoma), and mesenchymal elements (primary sarco- mas, not covered in this chapter). Hepatocellular carcinoma is the most common primary cancer of the liver and is a leading cause of death from cancer world- wide. Although it is uncommon in the United States, its incidence is rising. The majority of hepatocellular carcinomas arise in a background of chronic liver disease due to viral hepatitis (B or C) or ethanol abuse. Cirrhosis may dominate the clinical picture and determine the prognosis. Other important indicators of the outcome of hepatocellular carcinoma are resectability for cure and the extent of vascular invasion.
ANATOMY
Primary Site. The liver has a dual blood supply: the hepatic artery, which branches from the celiac artery, and the portal vein, which drains the intestine.
Blood from the liver passes through the hepatic vein and enters the inferior vena cava. The liver is divided into right and left lobes by a plane (Cantlie’s line) projecting between the gallbladder fossa and the vena cava and defined by the
middle hepatic vein (Figure 14.1). Couinaud refined knowledge about the func- tional anatomy of the liver and proposed division of the liver into four sectors (formerly called segments) and eight segments. In this nomenclature, the liver is divided by vertical and oblique planes or scissurae defined by the three main hepatic veins and a transverse plane or scissura that follows a line drawn through the right and left portal branches. Thus, the four traditional segments (right anterior, right posterior, left medial, and left lateral) are replaced by sectors (right anterior, right posterior, left anterior, and left posterior), and these sectors are divided into segments by the transverse scissura (Figure 14.2). The eight seg- ments are numbered clockwise in a frontal plane. Recent advances in hepatic
Right lobe
Cantlie's line
Hepatoduodenal ligament
Left lobe
FIGURE 14.1. Division of the liver into right and left lobes by the plane of Cantlie’s line.
Right scissura
Middle scissura
Left scissura
Cantlie's line I
II
III IV
V VI
VII VIII
Transverse scissura
FIGURE 14.2. Anatomy of the liver.
surgery have made possible anatomic (also called typical) resections along these planes.
Histologically, the liver is divided into lobules with central veins draining each lobule. The portal spaces between the lobules contain the intrahepatic bile ducts and the blood supply, which consists of small branches of the hepatic artery and portal vein (portal triads).
Regional Lymph Nodes. The regional lymph nodes are the hilar, hepatoduo- denal ligament lymph nodes, and caval lymph nodes, among which the most prominent are the hepatic artery and portal vein lymph nodes. Histologic ex- amination of a regional lymphadenectomy specimen will ordinarily include a minimum of three lymph nodes.
Nodal involvement beyond these lymph nodes is considered distant metas- tasis and should be coded as M1. Involvement of the inferior phrenic lymph nodes should also be considered M1.
Metastatic Sites. The main mode of dissemination of liver carcinomas is via the portal veins (intrahepatic) and hepatic veins. Intrahepatic venous dissemi- nation cannot be differentiated from satellitosis or multifocal tumors and is classified as multiple tumors. The most common sites of extrahepatic dissemi- nation are the lungs and bones. Tumors may extend through the liver capsule to adjacent organs (adrenal, diaphragm, and colon) or may rupture, causing acute hemorrhage and peritoneal carcinomatosis.
DEFINITIONS Primary Tumor (T)
TX Primary tumor cannot be assessed T0 No evidence of primary tumor
T1 Solitary tumor without vascular invasion (Figure 14.3)
T2 Solitary tumor with vascular invasion or multiple tumors, none more than 5 cm (Figures 14.4A, B)
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T1
FIGURE 14.3. T1 is defined as a solid tumor without vascular invasion, regardless of size.
Vascular invasion T2
A T2
£5 cm
£5 cm
£5 cm
B
FIGURE 14.4. A. All solitary tumors with vascular invasion, regardless of size, are classified T2. B. Multiple tumors, with none more than 5 cm, are classified T2.
T3 Multiple tumors more than 5 cm or tumor involving a major branch of the portal or hepatic vein(s) (Figures 14.5A, B)
T4 Tumor(s) with direct invasion of adjacent organs other than the gallblad- der or with perforation of visceral peritoneum (Figure 14.6)
Regional Lymph Nodes (N)
NX Regional lymph nodes cannot be assessed N0 No regional lymph node metastasis
N1 Regional lymph node metastasis (Figure 14.7) Distant Metastasis (M)
MX Distant metastasis cannot be assessed M0 No distant metastasis
M1 Distant metastasis
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T3
>5 cm
>5 cm
>5 cm
A
T3
>5 cm
B
FIGURE 14.5. A. Multiple tumors more than 5 cm are classified T3. B. A tumor involving a major branch of the portal or hepatic vein(s) is classified T3.
T4 T4
Perforated visceral peritoneum
Stomach
FIGURE 14.6. Two views of T4: tumor with perforation of the visceral
peritoneum(left of dotted line); tumor directly invading adjacent organs other than the gallbladder (right of dotted line, tumor invades stomach).
STAGE GROUPING
I T1 N0 M0
II T2 N0 M0
IIIA T3 N0 M0
IIIB T4 N0 M0
IIIC Any T N1 M0
IV Any T Any N M1
Hepatoduodenal ligament N1
FIGURE 14.7. N1 is defined as metastasis to regional lymph nodes.
