Gastrinoma and Zollinger-Ellison syndrome — what it is, and how it is confirmed

A gastrinoma is an uncommon neuroendocrine tumour that produces the hormone gastrin. Gastrin has one job: it tells the stomach to make acid. When a tumour produces it continuously, and in far greater quantity than the body ever asks for, the stomach is driven to pour out acid it does not need. The illness that follows is called Zollinger-Ellison syndrome. The tumour and the syndrome are two halves of one story — the gastrinoma is the source, and Zollinger-Ellison syndrome is what it does to you.

Most gastrinomas sit inside a small area of the upper abdomen that surgeons call the gastrinoma triangle: roughly the junction of the bile ducts above, the second and third parts of the duodenum below, and the neck and body of the pancreas to the side. A large share of them are in the wall of the duodenum rather than in the pancreas itself, so a search for “gastrinoma pancreas” shows you only half the picture. They are often small. Sometimes there is more than one. Both facts matter, because together they explain why finding one can take more than a single scan.

A gastrinoma belongs to the group of functioning neuroendocrine tumours — functioning meaning it secretes a hormone that causes symptoms, rather than sitting quietly and turning up on a scan done for another reason. That single distinction shapes the whole plan, and it is set out in more detail in functioning versus non-functioning pancreatic neuroendocrine tumours.

One more thing is worth saying at the start, because it is the fear most people arrive with. A gastrinoma is not pancreatic ductal adenocarcinoma, the common and aggressive pancreatic cancer that dominates almost everything written about this organ — the wider picture is in our complete guide to pancreatic cancer. Neuroendocrine tumours grow more slowly in most cases, respond to different treatments, and generally carry a considerably better outlook. That does not make a gastrinoma harmless. Many behave as malignant tumours, and spread to nearby lymph nodes or the liver is not unusual. But even then it can often be controlled over a long period. Serious, yes. The same disease as adenocarcinoma, no.

• Your ulcers have come back more than once despite completing proper treatment, and nobody has explained to you why.
• Ulcers were found beyond the usual site, or more than one was found at the same endoscopy.
• Testing for the stomach infection was negative and you do not take anti-inflammatory painkillers regularly.
• Severe reflux holds only at high doses of acid-suppressing medication, and breaks through whenever the dose is reduced.
• Long-standing diarrhoea sits alongside the ulcer or the reflux, and improves noticeably once acid is suppressed.
• A close relative has had a parathyroid or pituitary problem, or you have had unexplained high calcium or kidney stones.
• A scan has already reported a small pancreatic or duodenal lesion and you want to know whether it is a functioning tumour — how pancreatic neuroendocrine tumours are treated sets out what follows once one is confirmed.

1. 1

   The medication list comes first

   Before any blood result is trusted, we go through everything you take, including anything bought over the counter. Acid-suppressing medication of the proton-pump-inhibitor class raises gastrin by itself, so the test is planned around it rather than in spite of it.

   In-house at CION
2. 2

   Fasting gastrin, read alongside stomach acidity

   A fasting gastrin level is measured and interpreted together with how acidic the stomach actually is, usually with chromogranin A and routine bloods. A high gastrin with a stomach that is not acidic points somewhere else entirely.

   Ordered and reported in-house at CION
3. 3

   Endoscopy, and endoscopic ultrasound where needed

   A gastroscopy looks at the ulcers directly. Endoscopic ultrasound gives the close view of the duodenal wall and the pancreas that ordinary scans cannot, and can take a tissue sample at the same sitting.

   Coordinated with gastroenterology and endoscopy partners
4. 4

   Cross-sectional imaging to map it

   A pancreatic-protocol contrast CT, or an MRI, maps the tumour, the lymph nodes and the liver. This is the scan the whole plan is built on, and it is read specifically rather than glanced at.

   Ordered and reported in-house at CION
5. 5

   Receptor imaging when the tumour is hiding

   Gastrinomas usually carry somatostatin receptors on their surface, which makes DOTATATE PET imaging unusually good at finding small tumours that a CT reports as normal.

   Coordinated with partner imaging and nuclear medicine centres
6. 6

   Genetic counselling where the pattern fits

   Where you or a close relative has had parathyroid or pituitary disease, we discuss testing for the inherited MEN1 pattern, because the answer changes both the surveillance and the surgical approach.

   In-house at CION

Your first consultation is free and lasts 45 minutes. It is a proper review of your endoscopy report, your scans and your blood results rather than a booking appointment, and you should leave knowing what is confirmed, what is still an open question, and in what order the remaining questions get answered.

Delivered in-house at CION, across 35+ centres in Telangana and Andhra Pradesh: the medical management of acid over-production, at the doses this condition genuinely needs rather than the standard ones; ordering and reporting of fasting gastrin, chromogranin A and routine bloods; pancreatic-protocol contrast CT and MRI; systemic treatment for neuroendocrine tumours, including somatostatin-analogue-class therapy and, where the disease calls for it, mTOR-inhibitor-class or TKI-class treatment and chemotherapy; radiation where it has a role; genetic counselling for MEN1 and other inherited patterns; nutrition support; pain relief, psycho-oncology and supportive care; and long-term follow-up.

Coordinated with specialist HPB, gastroenterology, endoscopy and nuclear medicine partner centres, and may be billed there: gastroscopy and endoscopic ultrasound with biopsy; any operation to remove a gastrinoma, whether it sits in the duodenal wall or in the pancreas, along with every other pancreatic resection; ERCP and biliary or duodenal stenting; staging laparoscopy; coeliac plexus block; PET-CT and DOTATATE PET; and peptide receptor radionuclide therapy. We arrange these, we sit in on the decisions, and we tell you in advance where each one happens and who invoices you. We do not describe them as our own theatre or endoscopy lists, because they are not.

Two decisions dominate this condition, and keeping them apart is most of the battle. The first is controlling the acid, which can usually be done well and fairly quickly, and which is what stops the ulcers, the reflux and the diarrhoea. The second is what to do about the tumour itself — whether to remove it, and if so when, which depends on where it sits, whether there is more than one, and whether an inherited pattern is involved. Those are separate conversations on separate timelines, and conflating them is the commonest source of confusion we see. How pancreatic neuroendocrine tumours are treated covers the tumour-directed options in full, and pancreatic cancer treatment in Hyderabad sets out how the wider service is organised.

Medical disclaimer: This page explains what a gastrinoma is and how Zollinger-Ellison syndrome is investigated and managed, and is reviewed by a CION medical oncologist with reference to NCCN guidance on neuroendocrine and adrenal tumours. It is general information and not a substitute for an individual assessment; recurrent ulcers have many causes, most of them common and none of them cancer, and your own diagnosis and plan must be decided with your treating team. Medical management of acid over-production, fasting gastrin and chromogranin A testing, contrast CT and MRI ordering and reporting, systemic therapy for neuroendocrine tumours including somatostatin-analogue-class treatment, radiation where it has a role, genetic counselling, nutrition support, pain relief, psycho-oncology and long-term follow-up are delivered by CION. Gastroscopy and endoscopic ultrasound with biopsy, any operation to remove a gastrinoma and every other pancreatic resection, ERCP and biliary or duodenal stenting, staging laparoscopy, coeliac plexus block, PET-CT and DOTATATE PET, and peptide receptor radionuclide therapy are coordinated with specialist hepatobiliary, gastroenterology, endoscopy and nuclear medicine partner centres and may be billed there.