Adenoma and Adenocarcinoma of the Small Intestine
Grading / Staging / Report
Grading
- WHO accepts grading simply as Low vs. High grade
- CAP protocol requires well, moderately, poorly differentiated and undifferentiated designations
- Low grade ≥50% gland forming
- Well differentiated
- >95% gland forming
- Moderately differentiated
- 50-95% gland forming
- High grade <50% gland forming
- Poorly differentiated
- 5-49% gland forming
- Signet ring (>50% of cells signet ring)
- Undifferentiated
- <5% gland forming
Staging
- Use TNM staging:
- Ampulla and peri-ampullary
is different from rest of small intestine including duodenum
Size of tumor is not included in TNM but is predictiveTis Carcinoma in situ (no lamina propria invasion) T1 Confined to ampulla and sphincter of Oddi T2 Invasion of duodenal wall T3 Invasion of pancreas T4 Peripancreatic soft tissue or other organs/structures - <2.5 cm has 85% 5 year survival
- ≥2.5 cm has 20% 5 year survival
- Small intestine other than ampulla:
Tis Carcinoma in situ (no lamina propria invasion) T1 Lamina propria or submucosal invasion T2 Invasion of muscularis propria T3 Through muscularis propria ≤2 cm into subserosa, mesentery or retroperitoneum T4 Invasion >2 cm, serosal perforation, or into other organs/tissues including pancreas
- For ampulla, regional nodes include:
- Superior and inferior to head and body of pancreas
- Anterior and posterior pancreaticoduodenal
- Proximal and superior mesenteric
- Pyloric, pancreaticoduodenal, common bile duct or pericholedochal
- Hepatic artery nodes, infrapyloric, subpyloric
- Celiac, retroperitoneal, and lateral aortic
- Miscellaneous TNM issues
- Multiple simultaneous carcinomas
- Includes those diagnosed within 2 months
- Includes Tis lesions
- TNM should be reported for the lesion with the highest T score
- Add (m) or (2) etc. to indicate number of primary lesions e.g. pT3(m)
- Post-neoadjuvant therapy excision specimens
- TNM as usual but add prefix, e.g. ypT1
- Pools of mucin without epithelial cells are counted as negative at both the primary site and in lymph nodes
- Residual tumor in patient at end of surgical excision
- Either distant or at positive surgical margin
- Positive margin generally is interpreted as indication of residual neoplasm but should be discussed with surgeon
- Designate as R1 if microscopic
- Designate as R2 if macroscopic
- Recurrences
- Coded as rpT1 etc.
- Use usual TNM guidelines as for primary
- Label recurrence as located in proximal segment of anastomosis, except when that is ileum following a right colon resection
- Multiple simultaneous carcinomas
