Editing Pancreatic neuroendocrine tumours (section)

== '''Diagnosis/workup''' ==

* History - carefully screen for functional tumour symptoms
** Neuroglycopaenic symptoms
** Diarrhoea
** Ulcer diathesis
** Rash
* Family history
* Bloods
** Biochemical confirmation of functional symptoms
** Chromogranin-A: often co-released in many PNETs (functional and non-functional), potential marker of secretory activity, especially in non-functional tumours (may be elevated with PPIs, atrophic gastritis, or CKD or liver dysfunction)
* Imaging - localise PNET and check for metastases
** CT CAP - need early arterial phase
*** Hyper-enhancing 
*** Can see arterial blush
*** Isodense pre-contrast, enhance arterial phase, washout PV phase
*** Distending duodenum with water can help for small duodenal gastrinomas
** Gallium-68 DOTATATE PET, fused with CT
*** Sensitivity 80%, specificity 90%, and specificity nearly 100% for metastases seen outside pancreas
*** Lesions that take up tracer well, may respond better to somatostatin analogues
** FDG PET
*** Better than DOTATATE PET for poorly-differentiated tumours, which tend to be high-grade and without somatostatin receptors
** MRI
*** Low signal T1, high signal T2
*** Identifies all lesions >3cm, 50% of lesions 1-2cm, and no lesions <1cm
*** Useful for liver
** EUS
*** Better sensitivity than CT or MRI
*** Good for pancreatic head and duodenal wall
** Old - somatostatin receptor scintigraphy
*** Essentially replaced by DOTATATE PET
*** Useful adjunct in localisation if not seen on CT/MRI/EUS
*** Very good especially for gastrinomas, not as good for insulinomas and pancreatic adenocarcinoma
*** Lacks anatomic precision
*** Not very good if lesion <1cm
*** Overall sensitivity 70-90%, specificity nearly 100%
** Angiography
*** Can sometimes be useful if other studies can't locate it
*** Detects 70% of insulinomas >5mm