Lymphatic drainage of the stomach and duodenum

1. Origin

• Mucosal and submucosal lymphatic plexuses → collecting vessels in the subserosa
• Collecting vessels → follow the arteries to the nodes along them
• Final common path → coeliac nodes → cisterna chyli → thoracic duct → left subclavian vein
• Zones communicate freely → no fixed watershed between them

2. Course and relations

Stomach: 4 drainage zones

1. Superior gastric zone → along the left gastric artery to the coeliac nodes
   • Drains the lower oesophagus and most of the lesser curvature (proximal 2/3 of the stomach)
2. Suprapyloric zone → along the right gastric artery and portal vein
   • Drains the distal lesser curvature and pylorus
   • Efferents → hepatic and para-aortic nodes
3. Inferior gastric (subpyloric) zone → along the right gastroepiploic artery, in front of the pancreatic head
   • Drains the distal greater curvature, pylorus and duodenum
   • Efferents → superior mesenteric nodes
4. Pancreaticosplenic zone → along the left gastroepiploic and short gastric vessels to the splenic hilum
   • Drains the fundus and upper greater curvature

Gastro-oesophageal junction

• Gastric lymphatics → communicate with oesophageal lymphatics
• Proximal gastric cancer → spreads to lower mediastinal nodes

Duodenum

• Collecting trunks → over the anterior and posterior duodenal walls
• First drainage → anterior and posterior pancreaticoduodenal nodes
• Upper flow → pyloric and hepatic nodes → coeliac nodes
• Lower flow → superior mesenteric nodes → preaortic nodes

3. Lymph node stations (Japanese Gastric Cancer Association)

Perigastric (No. 1–6)

• No. 1 → right paracardial
• No. 2 → left paracardial
• No. 3a → lesser curvature, along branches of the left gastric artery
• No. 3b → lesser curvature, along the distal right gastric artery
• No. 4sa → left greater curvature, along the short gastric arteries
• No. 4sb → left greater curvature, along the left gastroepiploic artery
• No. 4d → right greater curvature, along the distal right gastroepiploic artery
• No. 5 → suprapyloric, along the proximal right gastric artery
• No. 6 → infrapyloric, down to the junction of the right gastroepiploic and anterior superior pancreaticoduodenal veins

Along the coeliac branches (No. 7–11)

• No. 7 → left gastric artery trunk
• No. 8a → anterosuperior common hepatic artery
• No. 8p → posterior common hepatic artery
• No. 9 → coeliac trunk
• No. 10 → splenic hilum
• No. 11p → proximal half of the splenic artery
• No. 11d → distal half of the splenic artery

Beyond the stomach (No. 12–20)

• No. 12a → hepatoduodenal ligament, along the proper hepatic artery
• No. 12b → hepatoduodenal ligament, along the bile duct
• No. 12p → hepatoduodenal ligament, along the portal vein
• No. 13 → posterior surface of the pancreatic head
• No. 14v → along the superior mesenteric vein (SMV)
• No. 14a → along the superior mesenteric artery (SMA)
• No. 15 → along the middle colic vessels
• No. 16 → para-aortic:
  • 16a1 → aortic hiatus
  • 16a2 → coeliac trunk to left renal vein
  • 16b1 → left renal vein to inferior mesenteric artery (IMA)
  • 16b2 → IMA to aortic bifurcation
• No. 17 → anterior surface of the pancreatic head
• No. 18 → inferior border of the pancreatic body
• No. 19 → infradiaphragmatic
• No. 20 → oesophageal hiatus

4. Extent of lymphadenectomy

Distal gastrectomy

1. D1 → No. 1, 3, 4sb, 4d, 5, 6, 7
2. D1+ → D1 plus No. 8a, 9
3. D2 → D1 plus No. 8a, 9, 11p, 12a

Total gastrectomy

1. D1 → No. 1–7
2. D1+ → D1 plus No. 8a, 9, 11p
3. D2 → D1 plus No. 8a, 9, 11p, 11d, 12a

Indications

• D1 or D1+ → early (cT1) node-negative cancer
• D2 → node-positive or cT2–T4 cancer
• No. 10 (splenic hilum) → not routine in D2; splenectomy adds morbidity without survival benefit
• No. 14v → added when No. 6 nodes are involved
• Adequate staging → ≥ 15 nodes examined

Older tier system

• N1 → perigastric (No. 1–6)
• N2 → coeliac branches (No. 7–11)
• N3 → hepatoduodenal ligament and mesenteric root (No. 12–14)
• N4 → para-aortic and middle colic (No. 15–16)

5. Clinical significance

• Gastric cancer → spreads along the arterial pathways; nodes are named by the artery they lie on
• Upper lymphatics blocked → retrograde spread to lower groups
• Virchow's node (left supraclavicular) → via the thoracic duct; Troisier's sign
• Irish's node → left axillary node
• Sister Mary Joseph nodule → umbilical metastasis
• Ampullary and periampullary cancer → pancreaticoduodenal nodes (No. 13, 17) → pancreaticoduodenectomy
• No. 6 dissection → follows the right gastroepiploic vein to its junction with the anterior superior pancreaticoduodenal vein