gastrocon 2016 - dr g.n ramesh describes how to diagnose nets
Post on 18-Jan-2017
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How do I diagnose NETs?
G N RameshASTER Medcity
Cochin
Nomenclature • Arising from Enterochromaffin cells • Differentiation / grading• ‘Carcinoids’ are the well differentiated tumors• Poorly differentiated tumors are referred to as
Neurendocrine carcinomas – small cell or large cell .
• Further nomenclatures are related to the origin and stage – foregut , midgut , hindgut , pancreatic , metastatic , functioning / non-functioning
Classification by origin
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Size is important
Clinical presentations
Case 1 : RB
• 56 yr old male with generalised abdominal pain . OGD – ‘severe PUD with gastric ulcers”
• Repeat OGD – large mass at angularis , erythematous mucosa with shallow ulceration
• CT – distal gastric mass - submucosal
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When to suspect?
• Multiple gastric lesions• Gastric lesions in patients with pernicious
anemia / chronic atrophic gastritis / MENs • Gastric growth which is not an
adenocarcinoma
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Jejunoileal NETs• Increased detection on endoscopy and
imaging• 60s and 70s ; arise from intraepithelial
endocrine cells• Most commonly located – distal 60 cms of
ileum • Abd pain 40% ; intermittent obstruction 25% ;
duodenal/biliary obstruction , intussusception • Metastasis – liver 47% if primary >2 cms ;
nodes 58% if primary > 1 cm
Appendix NET
• Most common neoplasm of the appendix• Incidental detection ; most often tip / distal
third of appendix ; 10 % base of appendix – obstruction
• 40s – 50s ( younger profile) – appendectomy related ; younger women who undergo pelvic surgeries
• Carcinoid syndrome related to metastasis
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Midgut NETs – when to suspect?
• Vague small bowel pain with mass• Carcinoid syndrome • Appendicitis with mass • Base of appendix tumor• Intussusception / mass with desmoplastic
reaction• Ulcerated small bowel growth • Multiple small bowel lesions
Hindgut NETs
• Usually nonsecretory , not associated with carcinoid syndrome even when metastatic
• Symptoms – mimic adenoca - altered bowel habits ; obstruction ; bleeding
Colonic NETs
• Elderly patients – 70s• Presentation – usually ‘adenoca like’• Rarely functional • Majority – rt colon particularly caecum • Symptoms related to size – ave size at
detection – 5 cms • 2/3 – local nodal / distant metastasis
Rectal NETs• Asymptomatic – found on colonoscopy • 60s• Uncommon manifestations – bleeding ; changed
bowel habits ; pain ;• Carcinoid syndrome very rare • 75-85% are localised – no mets• Size more than 2 cms – 25% metastasise to liver• Poor prognosis related to size , invasion into
muscularis propria , lymphovascular invasion , high mitotic rate ( > 2 per 50 HPF)
Hind gut NETs – when to suspect?
• Colonic growth that is not an adenoca• Rectal polyps ( submucosal) with or without
ulceration• Small colonic / rectal primary with multiple
large liver mets
When to suspect PNETs?
• Clinical syndromes • Well defined rounded lesions in the pancreas• Symptoms of excessive hormone production
Suspicion
Clinical Imaging – endoscopic/radiologic
Staging / origin CT / MRI + EUS DOTATATE scanning
Histology Resection / FNA / Biopsy
Markers Chromogranin A / Pancreatic polypeptide / both
Functioning / non-functioning Insulin / glucagon / VIP / gastrin
CT
• Most NETs are highly vascular ; enhance in arterial phase (20s ) ; washout in portal venous phase (70s ) .
• > 80% sensitivity • Small tumors – rounded enhancing lesions ,
some may be hypodense or cystic .• Non-functionin symptomatic lesions are often
larger > 3 cms
MRI
• Typically – low signals on T1 ; high signals on T2
• Sensitivity 85% ; specificty 100% ; PPV 100% ; NPV 73%
• Better for hepatic lesions
68 Ga – DOTATATE PET-CT imaging
• Improved detection and staging on P-NETs• Increased sensitivity for smaller lesions• Higher spatial resolution• Preferred over OCTREOSCAN
More studies
• Transhepatic portal venous sampling ( THPV)• Arterial stimulation and venous sampling
( ASVS )• Intraoperative Ultrasound • Hormonal studies
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