Stomach
General
Staging-neuroendocrine tumors
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TNM staging stomach neuroendocrine tumor
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Cite this page: Gonzalez RS. Staging-neuroendocrine tumors. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/stomachstagingneuroendocrine.html. Accessed May 30th, 2023.
Pathologic TNM staging of neuroendocrine tumors of the stomach, AJCC 8th edition
Definition / general
- Well differentiated neuroendocrine tumors of the stomach are covered by this staging system
- Not covered by this staging system are poorly differentiated neuroendocrine carcinomas of the stomach (click here)
ICD coding
- C7A.092: Malignant carcinoid tumor of the stomach
Primary tumor (pT)
- TX: Primary tumor cannot be assessed
- T0: No evidence of primary tumor
- T1: Invades the lamina propria or submucosa and is ≤ 1 cm in size
- T2: Invades the muscularis propria or is > 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 has occurred
- N1: Regional lymph node metastasis
Notes:
- Regional lymph nodes depend on the tumor site within the stomach:
- Greater curvature: greater curvature, greater omental, gastroduodenal, gastroepiploic, pyloric, and pancreaticoduodenal nodes
- Pancreatic and splenic areas: pancreaticolienal, peripancreatic, and splenic nodes
- Lesser curvature: lesser curvature, lesser omental, left gastric, cardioesophageal, common hepatic, celiac, and hepatoduodenal nodes
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 | M0
|
| Stage IV: | any T | any N | M1
|
Registry data collection variables
- Size of tumor (value or unknown)
- Depth of invasion
- Nodal status and number of nodes involved, if applicable
- Sites of metastasis, if applicable
- Ki67 index
- Mitotic count
- Histologic grading (from Ki67 and mitotic count): G1, G2, G3
- Preoperative pancreastatin level
- Preoperative gastrin level
- Preoperative CgA level
- Type of gastric neuroendocrine tumor (NET) (I, II, or III)
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
Based on AJCC 8th edition criteria, a well differentiated neuroendocrine tumor of the stomach that metastasized to regional lymph nodes and also to the lung would be staged as which of the following?
- pM0
- pM1a
- pM1b
- pM1c
Board review style answer #1
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