Small intestine & ampulla
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Staging-small intestine neuroendocrine tumors
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Staging neuroendocrine tumors small bowel[TIAB]
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Cite this page: Gonzalez RS. Staging-small intestine neuroendocrine tumors. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/smallbowelstagingneuroendocrine.html. Accessed September 25th, 2023.
Pathologic TNM staging of neuroendocrine tumors of the jejunum and ileum, AJCC 8th edition
Definition / general
- Well differentiated neuroendocrine tumors of the jejunum and ileum are
covered by this staging system
- Not covered by this staging system are well differentiated neuroendocrine
tumors of the ampulla or duodenum (use ampulla staging) or poorly
differentiated neuroendocrine carcinomas of the small intestine (use small bowel carcinoma staging)
ICD coding
- C7A.011: malignant carcinoid tumor of the jejunum
- C7A.012: malignant carcinoid tumor of the ileum
Primary tumor (pT)
- TX: primary tumor cannot be assessed
- T0: no evidence of primary tumor
- T1: invades lamina propria or submucosa and ≤ 1 cm in
size
- T2: invades muscularis propria or > 1 cm in size
- T3: invades through the muscularis propria into subserosal tissue without
penetration of overlying serosa
- T4: invades visceral peritoneum (serosa) or other organs or adjacent
structures
Regional lymph nodes (pN)
- NX: regional lymph nodes cannot be assessed
- N0: no regional lymph node metastasis
- N1: regional lymph node metastasis in < 12 nodes
- N2: large mesenteric masses (> 2 cm) or extensive nodal deposits (≥ 12), especially those that encase the superior mesenteric vessels
Notes:
- Regional lymph nodes include superior mesenteric and mesenteric nodes;
posterior cecal nodes also apply for terminal ileum lesions
- 2 cm cutoff for including mesenteric masses in N categorization may be
suboptimal (Mod Pathol 2018 May 24 [Epub ahead of print])
Prefixes
- (m): multiple primary lesions (provide stage for the most advanced lesion)
- r: recurrent tumor stage
Stage grouping
- Stage I:T1 N0 M0
- Stage II:T2 - 3 N0 M0
- Stage III:T4 N0 M0
- any T N1 - 2 M0
- Stage IV:any T any N M1
Registry data collection variables
- Size of tumor (value or unknown)
- Tumor focality (unifocal or multifocal)
- Depth of invasion
- Nodal status and number of nodes involved, if applicable
- Sites of metastasis, if applicable
- NKA (neurokinin A) level
- Pancreastatin level
- Ki67 index
- Mitotic count
- Histologic grading (from Ki67 and mitotic count): G1, G2, G2
Histologic grade
- Grading is not formally part of the staging system
- Most pathologists use the European Neuroendocrine Tumor Society (ENETS) / WHO grading criteria:
- Grade 1: mitotic rate < 2 per 10 high power fields and Ki67 rate < 3%
- Grade 2: mitotic rate 2 - 20 per 10 high power fields or Ki67 rate 3 - 20%
- Grade 3: mitotic rate > 20 per 10 high power fields or Ki67 rate > 20%
Histopathologic type
- Neuroendocrine tumor (NET) G1 (carcinoid)
- Neuroendocrine tumor (NET) G2
Board review style question #1
A patient undergoes resection for jejunal neuroendocrine tumors. Three tumors
are present – one smaller than 1 cm, one larger than 1 cm and invading the
muscularis propria and one larger than 1 cm and invading the subserosa. Using
AJCC 8th edition criteria, how would the pathologic T category be
reported for this patient?
- Separate complete staging for each primary focus
- pT1/T2/T3
- pT1(1)T2(1)T2(1)
- pT3(m) or pT3(3)
Board review style answer #1
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