GALLBLADDER (ICD‐O‐3 C23.9 and C24.0)

Rules for Classification

The classification applies only to carcinomas of the gallbladder and cystic duct. There should be histological confirmation of the disease.

Regional Lymph Nodes (Fig. 216)

Regional lymph nodes are limited to the hepatic hilus (including nodes along the common bile duct, hepatic artery, portal vein and cystic duct).

Coeliac, periduodenal, peripancreatic and superior mesenteric artery node involvement is considered distant metastasis (M1).

Schematic illustration of coeliac, periduodenal, peripancreatic and superior mesenteric artery node involvement is considered distant metastasis. — **Fig. 212**

TNM Clinical Classification

T – Primary Tumour

TX	Primary tumour cannot be assessed
T0	No evidence of primary tumour
Tis	Carcinoma in situ
T1	Tumour invades lamina propria or muscular layer (Fig. 213)
	T1a	Tumour invades lamina propria
	T1b	Tumour invades muscular layer
T2	Tumour invades perimuscular connective tissue; no extension beyond serosa or into liver (Fig. 214)
	T2a	Tumour invades perimuscular connective tissue on the peritoneal side with no extension to the serosa
	T2b	Tumour invades perimuscular connective tissue on the hepatic side with no extension into the liver
T3	Tumour perforates the serosa (visceral peritoneum) and/or directly invades the liver and/or one other adjacent organ or structure, such as stomach, duodenum, colon, pancreas, omentum, extrahepatic bile ducts (Figs. 215, 216)
T4	Tumour invades main portal vein or hepatic artery or invades two or more extrahepatic organs or structures (Figs. 217, 218)

Schematic illustration of tumour invades lamina propria or muscular layer.

Schematic illustration of tumour invades perimuscular connective tissue; no extension beyond serosa or into liver. — **Fig. 214**

Schematic illustration of tumour perforates the serosa and directly invades the liver and one other adjacent organ or structure, such as stomach, duodenum, colon, pancreas, omentum, extrahepatic bile ducts. — **Fig. 215**

Schematic illustration of tumour invades main portal vein or hepatic artery or invades two or more extrahepatic organs or structures. — **Fig. 217**

N – Regional Lymph Nodes (Figs. 219, 220)

NX	Regional lymph nodes cannot be assessed
N0	No regional lymph node metastasis
N1N2	Metastases to 1‐3 nodesMetastases to 4 or more nodes

Schematic illustration of Metastases to 1-3 nodes. — **Fig. 219**

Schematic illustration of Metastases to 4 or more nodes. — **Fig. 220**

M – Distant Metastasis

M0	No distant metastasis
M1	Distant metastasis

TNM Pathological Classification

The pT and pN categories correspond to the T and N categories.

pM1	Distant metastasis microscopically confirmed

Note

pM0 and pMX are not valid categories.

pN0

Histological examination of a regional lymphadenectomy specimen will ordinarily include 3 or more lymph nodes. If the regional lymph nodes are negative, but the number ordinarily examined is not met, classify as pN0.