17 Ampulla of Vater
(Carcinoid tumors and other neuroendocrine tumors are not included.)
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SUMMARY OF CHANGES
• There is no longer a distinction between T3 and T4 on the basis of the depth of pancreatic invasion.
• The stage grouping has been revised.
• Stage I has been replaced with Stage IA and Stage IB.
• Stage II has been replaced with Stage IIA and Stage IIB.
• Node positive disease has been moved to Stage IIB to retain consistency with the staging of tumors of the bile duct and of the pancreas.
C24.1 Ampulla of Vater
INTRODUCTION
The ampulla of Vater is strategically located at the confluence of the pancreatic and common bile ducts. Most tumors that arise in this small structure obstruct the common bile duct, causing jaundice, abdominal pain, and occasionally pancreatitis. Clinically and pathologically, carcinomas of the ampulla may be difficult to differentiate from those arising in the head of the pancreas or in the distal segment of the common bile duct. Primary cancers of the ampulla are not common, although they constitute a high proportion of the malignant tumors occurring in the duodenum. Tumors of the ampulla must be differentiated from those arising in the second part of the duodenum and invading the ampulla, which are staged as small bowel tumors. Carcinomas of the ampulla and peri- ampullary region are often associated with the familial adenomatous polyposis syndrome.
ANATOMY
Primary Site. The ampulla is a small dilated duct less than 1.5 cm long, formed in most individuals by the union of the terminal segments of the pancreatic and common bile ducts (Figure 17.1). In 42% of individuals, however, the ampulla is the termination of the common duct only, the pancreatic duct having its own entrance into the duodenum adjacent to ampulla. In these individuals, the ampulla may be difficult to locate or even nonexistent. The ampulla opens into the duodenum, usually on the posterior-medial wall, through a small mucosal elevation, the duodenal papilla, which is also called the ampulla of Vater.
Although carcinomas can arise in the mucosa of either the lining of the ampulla or the duodenal surface of the duodenal papilla, they most commonly arise near the junction of the two types of mucosa at the ampullary orifice. Nearly all cancers that arise in this area are well-differentiated adenocarcinomas. They have a variety of designations, including carcinoma of the ampulla of Vater, carci-
noma of the periampullary portion of the duodenum, and carcinoma of the peripapillary portion of the duodenum. It may not be possible to determine the exact site of origin for large tumors.
Regional Lymph Nodes. A rich lymphatic network surrounds the pancreas and periampullary region, and accurate tumor staging requires that all lymph nodes that are removed by analyzed. Optimal histologic examination of a pan- creaticoduodenectomy specimen should include analysis of a minimum of 10 lymph nodes. The regional lymph nodes are the peripancreatic lymph nodes, which also include the lymph nodes along the hepatic artery, celiac axis, and pyloric regions (Figures 17.2, 17.3). Anatomic division of regional lymph nodes is not necessary; however, separately submitted lymph nodes should be reported as submitted.
Ampulla of Vater C24.1
Extrahepatic bile ducts C24.0
FIGURE 17.1. Anatomic site of the ampulla of Vater.
Superior to head Cystic duct node
Pyloric Hepatic nodes
Splenic nodes Superior
to body
Inferior to head
Inferior to body
Inferior to tail Superior
pancreaticoduodenal nodes (Anterior and posterior) Inferior
pancreaticoduodenal nodes (Anterior and posterior)
Inferior pancreatic nodes Superior pancreatic nodes
Hilum of spleen Superior
to tail
FIGURE 17.2. Regional lymph nodes of the ampulla of Vater.
Metastatic Sites. Tumors of the ampulla may infiltrate adjacent structures, such as the wall of the duodenum, the head of the pancreas, and extrahepatic bile ducts. Metastatic disease is most commonly found in the liver and peri- toneum and is less commonly seen in the lungs and pleura.
DEFINITIONS Primary Tumor (T)
TX Primary tumor cannot be assessed T0 No evidence of primary tumor Tis Carcinoma in situ
T1 Tumor limited to ampulla of Vater or sphincter of Oddi (Figure 17.4) T2 Tumor invades duodenal wall (Figure 17.5)
T3 Tumor invades pancreas (Figure 17.6)
T4 Tumor invades peripancreatic soft tissues or other adjacent organs or structures (Figure 17.7)
Regional Lymph Nodes (N)
NX Regional lymph nodes cannot be assessed N0 No regional lymph node metastasis
N1 Regional lymph node metastasis (Figures 17.8A–C for tumors located in the head of the pancreas)
Distant Metastasis (M)
MX Distant metastasis cannot be assessed M0 No distant metastasis
M1 Distant metastasis (Figures 17.9A, B)
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Superior mesenteric nodes Hepatic
nodes
Celiac nodes
Splenic nodes
Superior pancreatic nodes
FIGURE 17.3. Regional lymph nodes to the ampulla of Vater, namely the proximal mesenteric and common bile duct nodes. View shows the pancreatic body cut away to reveal the proximal mesenteric lymph nodes.
T1 T1
FIGURE 17.4. Two views of T1: tumor limited to ampulla of Vater (below dotted line) or sphincter of Oddi (tumor shown above dotted line).
T2
FIGURE 17.5. T2 tumor invading duodenal wall.
T3
FIGURE 17.6. T3 tumor invading pancreas.
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T4
FIGURE 17.7. T4 tumor invading peripancreatic soft tissues or other adjacent organs or structures.
N1 Common bile duct
Portal
vein Aorta
A
FIGURE 17.8. A. N1 is defined as regional lymph node metastasis.
N1
Not regional lymph nodes
B
N1
Not regional lymph nodes Portal vein
Pancreatico- duodenal artery
Superior mesenteric artery
Splenic vein Splenic artery Left gastric artery Common
hepatic artery
Superior mesenteric vein
C
FIGURE 17.8. B, C. N1 is defined as regional lymph node metastasis.
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M1
Not regional lymph nodes
A
M1
Not regional lymph nodes
B
FIGURE 17.9. A. M1 is defined as distant metastasis, here to those of the tail of the pancreas. B. M1 is defined as distant metastasis, here to the splenic lymph nodes.
STAGE GROUPING
0 Tis N0 M0
IA T1 N0 M0
IB T2 N0 M0
IIA T3 N0 M0
IIB T1 N1 M0
T2 N1 M0
T3 N1 M0
III T4 Any N M0
IV Any T Any N M1
