NEUROENDOCRINE TUMOURS OF THE GASTROINTESTINAL TRACT


WELL‐DIFFERENTIATED NEUROENDOCRINE TUMOURS OF THE GASTROINTESTINAL TRACT


Rules for Classification


This classification system applies to well‐differentiated neuroendocrine tumours (carcinoid tumours and atypical carcinoid tumours) of the gastrointestinal tract, including the pancreas. Neuroendocrine tumours of the lung should be classified according to criteria for carcinoma of the lung. Merkel cell carcinoma of the skin has a separate classification.


High‐grade neuroendocrine carcinomas are excluded and should be classified according to criteria for classifying carcinomas at the respective site.


Histopathological Grading


The following grading scheme has been proposed for all gastrointestinal neuroendocrine tumours (carcinoids):



















Grade Mitotic count (per 10 HPF)1 Ki‐67 index (%)2
G1 < 2 ≤ 2
G2 2–20 3–20
G3 > 20 > 20

Notes


1 10 HPF: high power field = 2 mm2, at least 40 fields (at 40× magnification) evaluated in areas of highest mitotic density.


2 MIB1 antibody; % of 500–2,000 tumour cells in areas of highest nuclear labelling.


All Grade 3/high‐grade tumours should be classified according to criteria for classifying carcinoma at the respective sites.


Stomach


TNM Clinical Classification


T – Primary Tumour





















TX Primary tumour cannot be assessed
T0 No evidence of primary tumour
T1 Tumour invades the mucosa or submucosa and is no greater than 1 cm in greatest dimension (Fig. 245)
T2 Tumour invades muscularis propria or is more than 1 cm in greatest dimension (Fig. 245)
T3 Tumour invades subserosa (Fig. 245)
T4 Tumour perforates visceral peritoneum (serosa) (Fig. 246) or other organs or adjacent structures (Fig. 247)
Schematic illustration of tumour invades the mucosa or submucosa and is no greater than 1 cm in greatest dimension.

Fig. 245

Schematic illustration of tumour perforates visceral peritoneum.

Fig. 246

Schematic illustration of other organs or adjacent structures.

Fig. 247


Note


For any T, add (m) for multiple tumours.

Schematic illustration of Regional lymph node metastasis.

Fig. 248


N – Regional Lymph Nodes












NX Regional lymph nodes cannot be assessed
N0 No regional lymph node metastasis
N1 Regional lymph node metastasis (Fig. 248)

M – Distant Metastasis


















M0 No distant metastasis
M1 Distant metastasis

M1a Hepatic metastasis(es) only

M1b Extrahepatic metastasis(es) only

M1c Hepatic and extrahepatic metastases

Duodenum, Ampulla, Jejunum, Ileum


TNM Clinical Classification


T – Primary Tumour



















TX Primary tumour cannot be assessed
T0 No evidence of primary tumour
T1 Ampullary: Tumour 1 cm or less in greatest dimension and confined within the sphincter of Oddi

Duodenal, Jejunum and Ileum: Tumour invades mucosa or submucosa and 1 cm or less in greatest dimension (Fig. 249)
T2 Ampullary: Tumour invades through sphincter into duodenal submucosa or muscularis propria, or more than 1 cm in greatest dimension (Fig. 249)

Duodenal, Jejunum and Ileum

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Dec 15, 2022 | Posted by in ONCOLOGY | Comments Off on NEUROENDOCRINE TUMOURS OF THE GASTROINTESTINAL TRACT

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