This document discusses carcinoid tumors, which are rare neuroendocrine tumors. It covers their incidence, locations of origin in the gastrointestinal tract, histological classifications based on differentiation and proliferation rates, WHO grading system, clinical features and symptoms, diagnosis methods, staging system, treatment approaches based on localization and metastasis, risks of carcinoid crisis during surgery, follow up protocols, and references consensus guidelines for further reading.

1. CARCINOID TUMORS
MR.MEKKI HASSAN
POST CCT COLORECTAL FELLOW
BRADFORD TEACHING HOSPITALS FOUNDATION TRUST

2. INTRODUCTION
• Rare neuroendocrine tumors
• Incidence 1.1-2/100000
• 70 % in GIT

3. EMBRYOLOGICAL CLASSIFICATION
• Foregut Carcinoids (stomach ,duodenum , Pancrease ,lung and
thymus)
• Midgut Carcinoids (small bowel 30%- proximal 2/3 of colon)
• Hindgut Carcinoids (colon and rectum)

4. HISTOLOGICAL CLASSIFICATION
• Cells of origin (classical – originate from enterochromaffin cells
stain + with silver stain ,non classical- neuro endocrine
tumours , atypical – goblet cells ,no somatostatin receptors)
• Differentiation : depend on mitotic index and proliferative
index which assess by Ki67 stain: range from G1- well
differentiated (functioning )to G3- poorly differentiated (non
functioning )

5. WHO CLASSIFICATION
Grade Ki67 Mitotic index
G1 <2% <2
G2 2-20% 2-20
G3 >20% >20

6. CLINICAL FEATURES
• Asymptomatic
• Anemia
• Abdominal pain
• Rectal pain /bleeding
• Carcinoid syndrome (5%) – liver metastasis :
Diarrhoea – flushing- bronchospasm-tricuspid valve fibrosis –
pellagra :Diarrhoea , dermatitis , dementia)

7. DIAGNOSIS
• Histology of resected specimens
• Blood tests – used usually for follow up :24 hr urine 5HIAA , plasma
Chromogranin A level.
• Endoscopy : OGD , colonoscopy ,Capsular endoscopy)
• Imaging :
-Somatostatin receptor scintigraphy – used for lesion localisation
-Staging :
CTTAP
MRI /endoanal Us – for rectal carcinoids

8. STAGING (TNM)
tumor nodes met
T1a < 1cm N1 nodes +ve M1
T1b 1-2 cm
T2 2-4 cm
T3 >4cm
T4 breach peritoneum

9. TREATMENT (NET MDT?)
• Localised disease :
• Appendix :
<2cm – appendectomy ,>2cm , +ve L.nodes .mesoappendix invasion >3mm
,incomplete resection – Right hemicolectomy
• Small bowel : (flat lesions , large L.nodes ,mesenteric dysmoplastic reaction) –
resection of bowel with affected mesenteric segment +anastomosis
• Colon : resection +anastomosis
• Rectum:<2cm TEMS/local excision ,>2cm TME resection
• Metastatic disease: somatostatin receptor analogues,Cytotoxis therapy

10. CARCINOID CRISIS
• Tumor manipulation during surgery related serotonin surg
• C/F : hypotension , hyperthermia , bronchospasm.
• Predictors : cardiac carcinoids on echo ,elevated preop 5HIAA,CagA,
high tumor load .
• Prophylaxis :
-Preop: octreotide for 2/52
-IntraOp :octreotide infusion
-PostOp: Octreotide for 1/52

11. FOLLOW UP ( NET MDT?)
>1 year 1-10 years >10 years
3- 12 monthly
History and physical
examination +
biochemistry * + cross-
sectional imaging (CT/MRI)
Frequency: 6–12 monthly
(ENETS) / every 1–2 years
(CommNETs/NANETS/NCC
N).
Examinations: History and
physical examination +
biochemistry * + cross-
sectional imaging (CT/MRI)
ENETS guidelines suggest 2
yearly SSTR imaging if
positive at diagnosis
Individualised decision to
continue; recommended
life-long (ENETS)

12. FURTHER READING
• Consensus Guidelines for the Management and Treatment of
Neuroendocrine Tumors
• Pancreas. 2013 May; 42(4): 557–577.
• doi: 10.1097/MPA.0b013e31828e34a4