Zollinger-Ellison Syndrome (Gastrinoma): Causes, Symptoms, and Treatment Options
Zollinger-Ellison syndrome (ZES) was first described in 1955, in a work published in Annals of Surgery by Dr. Robert M. Zollinger and Dr. Edwin H. Ellison, surgeons at Ohio State University. Their study documented a series of cases of recurrent peptic ulcers, unusually localized in the proximal portion of the jejunum, characterized by resistance to conventional treatments and associated with severe gastric hypersecretion. These clinical observations, apparently atypical for classic ulcer pathology, led to the formulation of the hypothesis of the existence of a distinct pathological entity, with different etiological mechanisms.
The defining moment in delimiting the syndrome was the identification of pancreatic or duodenal tumors—later called gastrinomas—formed from non-beta cells, capable of autonomously secreting excessive amounts of gastrin. Since then, Zollinger-Ellison syndrome has been studied extensively, being understood today as a rare condition, but with significant implications for the digestive system and specific therapeutic needs.
In this article, the physiopathological foundations, clinical manifestations, current diagnostic methods, and treatment options will be explored in detail, offering a clear picture of this complex and challenging pathology.
What is Zollinger-Ellison Syndrome?
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*Zollinger-Ellison Syndrome (ZES)* was first described in 1955 by American surgeons Dr. Robert Zollinger and Dr. Edwin Ellison, who published their observations in *Annals of Surgery*. Their studies focused on a series of patients with recurrent peptic ulcers, unusually located in the proximal jejunum, associated with severe gastric hypersecretion and resistance to standard medical and surgical treatments, including gastrectomy. Subsequent investigations led to the identification of a neuroendocrine tumor, called a gastrinoma, responsible for the uncontrolled production of gastrin, a hormone that stimulates gastric acid secretion.
Histologically, gastrinomas are located in the pancreas or duodenum in over 80% of cases, often being multiple, with approximately one-third being malignant. The primary effect of hypergastrinemia is massive hydrochloric acid hypersecretion, leading to the development of deep, recurrent, and often refractory gastric and duodenal ulcers that are resistant to conventional antisecretory therapy. Symptoms include epigastric pain, retrosternal burning, chronic diarrhea, and, in some cases, malabsorption syndromes.
MEN1 Disease and its Association with Gastrinomas
An important component of the disease is its association with Multiple Endocrine Neoplasia type 1 (MEN1)—a rare genetic disorder with autosomal dominant inheritance, affecting the parathyroid glands, pituitary gland, and pancreas. In the context of MEN1, approximately 25-30% of patients develop gastrinomas, necessitating a multidisciplinary approach and extensive family screening, given the hereditary nature of the syndrome.
In addition to the specific treatment of acid secretion (proton pump inhibitors, surgical interventions, and targeted therapies for gastrinomas), patients may benefit from adjuvant support to balance gut flora, which is frequently disrupted by acid hypersecretion and the side effects of antisecretory therapy. In this regard, the use of a supplement such as Premium Probiotic – Prebiotic Vegan, which combines active probiotic strains with prebiotics, can contribute to restoring microbiota homeostasis, supporting digestion, and reducing intestinal discomfort associated with Zollinger-Ellison syndrome. This integrative approach plays a useful role in supporting gastrointestinal function and improving patients’ quality of life.
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Causes of Zollinger-Ellison Syndrome
The etiology of Zollinger-Ellison Syndrome (ZES) remains incompletely understood, but advances in understanding its pathogenesis have highlighted both genetic implications and potential environmental factors. As previously mentioned, the condition is defined by the development of one or more gastrinomas – gastrin-secreting neuroendocrine tumors – predominantly located in the pancreas or duodenum, but with the potential for ectopic occurrence, including in regional lymph nodes. Furthermore, these tumors induce marked hypergastrinemia, responsible for gastric hydrochloric acid hypersecretion and associated clinical manifestations, such as refractory peptic ulcer disease or secretory diarrhea.
Although most cases are sporadic, without a directly identifiable cause, approximately 25–30% of patients present with an hereditary form associated with Multiple Endocrine Neoplasia type 1 (MEN1) – an autosomal dominant disorder caused by inactivating mutations in the MEN1 gene, which codes for the menin protein, a tumor suppressor. Inactivation of this gene favors uncontrolled proliferation of cells in endocrine glands, including the endocrine pancreas, parathyroid glands, and pituitary gland. In this genetic context, gastrinomas are frequently multiple, have an early onset, and are associated with other functional endocrine tumors.
In cases of non-MEN1 forms, somatic acquired mutations in genes involved in the regulation of hormone secretion and the cell cycle are presumed to be involved, but the exact molecular mechanisms are not yet fully characterized. Potential environmental factors – such as chronic exposure to chemicals or radiation – have also been proposed, but evidence remains limited and inconsistent, requiring further studies.
Epidemiologically, the syndrome most commonly appears between the third and fifth decades of life, with a slightly higher incidence in males. Although rare, with an estimated incidence of approximately 1 case per million people annually, ZES requires special clinical attention due to the oncological risk (one-third of gastrinomas can be malignant) and severe gastrointestinal complications.
Symptoms of Zollinger-Ellison Syndrome
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Recognizing the symptoms of Zollinger-Ellison Syndrome (ZES) is essential for establishing an early diagnosis and initiating appropriate treatment, given the often insidious and variable nature of its clinical manifestations. The symptomatic spectrum is broad, and their intensity largely depends on the size, location, and secretory activity of the gastrinomas.
In most cases, the clinical picture is dominated by typical peptic ulcer symptoms: persistent epigastric pain, burning or pressing in nature, aggravated postprandially, and often refractory to usual antisecretory therapy. In some situations, “silent” ulcers may occur without obvious symptoms, especially in early stages or in the presence of small tumors.
A frequently encountered symptom is chronic diarrhea, present in over two-thirds of patients. This is a combined result of excessive gastric acid hypersecretion, which inactivates digestive enzymes and irritates the intestinal lining, and direct stimulation of intestinal motility by gastrin. Diarrhea can be severe, watery, and may be accompanied by malabsorption, with electrolyte losses and dehydration.
Intense gastroesophageal reflux is another common manifestation, reflecting prolonged exposure of the esophagus to excess gastric acid. Patients may complain of heartburn, acid regurgitation, retrosternal burning sensation, and in advanced forms, may develop erosive esophagitis or esophageal strictures.
As the syndrome progresses, systemic signs may appear, such as unintentional weight loss, anemia (secondary to chronic bleeding or iron malabsorption), nausea, recurrent vomiting, and early satiety, especially in patients with extensive gastric involvement.
Consequently, the identification of these symptoms, particularly in association with resistance to conventional treatments for ulcer or reflux, should raise clinical suspicion for Zollinger-Ellison syndrome, prompting a thorough diagnostic evaluation. An early diagnosis can prevent severe complications and allow for more effective therapeutic control of the condition.
Diagnosis of Zollinger-Ellison Syndrome
Establishing a diagnosis for Zollinger-Ellison Syndrome (ZES) requires a methodical approach, combining careful clinical evaluation with paraclinical and high-resolution imaging investigations. Due to the often non-specific symptomatic picture, which overlaps with other digestive conditions, accurate disease identification necessitates the correlation of multiple biochemical and morphological criteria.
Clinical assessment begins with a detailed medical history, documenting the presence of suggestive symptoms – recurrent epigastric pain, chronic diarrhea, severe reflux – as well as personal or family history of endocrine disorders, particularly Multiple Endocrine Neoplasia type 1 (MEN1). Physical examination may reveal abdominal tenderness or indirect signs of ulcerative complications.
From a biochemical standpoint, determining the serum gastrin level is a fundamental test. A significantly elevated value, in the presence of low gastric pH, suggests functional hypergastrinemia. In cases where the diagnosis remains uncertain, a secretin stimulation test is used to differentiate Zollinger-Ellison syndrome from other causes of hyperacidity or secondary hypergastrinemia.
Digestive Endoscopy – Role and Additional Techniques
Upper gastrointestinal endoscopy plays a central role in identifying ulcerative lesions and ruling out other organic causes. It also allows for the collection of duodenal biopsies for histopathologic analysis. In cases where lesions are subtle or endoscopically invisible, high-resolution ecoendoscopy is employed, allowing for in-depth visualization of the gastrointestinal wall and perivisceral structures.
To locate gastrinomas and assess lesion extent, advanced imaging techniques are utilized: computed tomography (CT), magnetic resonance imaging (MRI), and particularly, somatostatin receptor scintigraphy (Octreoscan or Gallium-68 PET-CT). These methods enable the identification of primary tumor formations as well as the detection of potential metastases, especially in the liver or lymph nodes.
Since the symptomatology of Zollinger-Ellison syndrome can mimic other digestive pathologies – such as peptic ulcer disease, gastroesophageal reflux disease, and inflammatory bowel diseases or malabsorption syndromes – a rigorous differential diagnosis is essential. An accurate diagnosis, based on a comprehensive evaluation protocol, is crucial for initiating targeted treatment and preventing long-term complications.
Treatment of Zollinger-Ellison Syndrome
The management of Zollinger-Ellison syndrome aims at both suppressing gastric acid hypersecretion and controlling the tumor through surgical interventions or specific oncological therapies. The therapeutic approach is personalized, depending on the location, number, and biological behavior of the gastrinomas, as well as the presence or absence of metastases.
The first line of treatment involves proton pump inhibitors (PPIs), administered at significantly higher doses than those used for classic peptic ulcer disease. These pharmacological agents act by irreversibly inhibiting the H⁺/K⁺-ATPase in gastric parietal cells, drastically reducing acid secretion. Twice-daily administration ensures effective acid control throughout the day and night, promoting the healing of mucosal lesions and reducing dyspeptic symptoms.
However, surgical intervention remains the only potentially curative option for localized forms of the disease. Pancreatic enucleation or partial resection are recommended for isolated pancreatic gastrinomas, while duodenal tumors may require duodenotomy with local excision or, in complex cases, pancreaticoduodenectomy (Whipple procedure). When resectable liver metastases are present, segmental liver resection may be indicated for palliative or curative purposes, depending on tumor extent.
For advanced, unresectable metastatic disease, targeted oncological therapies are used. Somatostatin analogs (e.g., octreotide, lanreotide) inhibit gastrin secretion and can stabilize tumor progression. Tyrosine kinase inhibitors (such as sunitinib) and agents targeting the mTOR pathway (e.g., everolimus) are used in the treatment of pancreatic neuroendocrine tumors, providing tumor control and improvement of systemic symptoms.
In cases resistant to pharmacological or surgical therapy, palliative strategies such as hepatic embolization, internal radiotherapy, or systemic chemotherapy may be considered based on the patient’s clinical and molecular profile. The choice of therapeutic regimen is made by a multidisciplinary team, including gastroenterologists, surgeons, oncologists, and nuclear medicine specialists, with the aim of ensuring integrated and effective treatment.
Complications and Prognosis for Patients with Zollinger-Ellison
Zollinger-Ellison syndrome, through persistent gastrin hypersecretion, can over time lead to a series of digestive complications. Zollinger-Ellison syndrome, through persistent gastric acid hypersecretion, can over time lead to a series of digestive complications. Zollinger-Ellison syndrome can lead to metabolic complications over time. These complications primarily occur when the diagnosis is delayed. These complications primarily occur when treatment is not optimized. The severity of these complications depends on the progression of mucosal lesions. It depends on the response to therapy. It depends on any associated comorbidities.
As the disease progresses, the risk of ulcerative complications increases significantly. Among the most severe is gastrointestinal perforation. Gastrointestinal perforation is a life-threatening medical emergency. Among the most severe are digestive hemorrhages. Hemorrhages manifest as hematemesis. Hemorrhages manifest as melena. Repeated lesions can promote pyloric stenosis. Repeated lesions can promote duodenal stenosis. These cause obstructions. They require endoscopic treatment. They require surgical treatment. Furthermore, chronic exposure of the esophagus to acid can lead to Barrett’s esophagus. Barrett’s esophagus is a structural change of the epithelium with malignant potential. This requires periodic endoscopic monitoring.
Beyond the digestive system, prolonged hypergastrinemia can also influence bone metabolism. It favors the development of osteoporosis. It favors the development of related complications, such as spontaneous fractures. Simultaneously, anemia may occur secondary to occult bleeding. Anemia can occur due to malabsorption of vitamin B12. This is a consequence of altered gastric pH. It is a consequence of parietal cell damage.
The prognosis in Zollinger-Ellison syndrome varies depending on several clinical factors. Localized forms, diagnosed early, have a favorable prognosis. This is true without nodal invasion. It is true without liver metastases. The prognosis is particularly favorable in cases of complete tumor resection. Pancreatic tumors tend to have a more aggressive behavior than duodenal tumors. The presence of MEN1 syndrome complicates management. It offers the advantage of potential early diagnosis through genetic screening.
Living with Zollinger-Ellison Syndrome
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Long-term clinical management of Zollinger-Ellison syndrome involves an extensive therapeutic strategy. This extends beyond pharmacological intervention. It includes supportive measures adapted to the patient’s daily realities. Strict adherence to the therapeutic regimen is an essential component. In particular, correct administration of proton pump inhibitors is essential. In particular, consistent administration of proton pump inhibitors is essential. The goal is to maintain clinical balance. The goal is to prevent the recurrence of ulcerative manifestations.
Self-management of symptoms involves careful monitoring of any variations. These variations can be in pain intensity. These variations can be in pain frequency. These variations can be in digestive disorders. These variations can be in other signs of decompensation. Effective communication with the medical team facilitates prompt adjustment of treatment. Adjustment is made according to the disease’s dynamics. Adjustment is made according to individual tolerance to medication.
In addition to drug treatment, lifestyle changes play a significant adjuvant role. A fractionated diet helps reduce dyspeptic symptoms. A balanced diet helps reduce dyspeptic symptoms. A diet low in acidic foods helps reduce dyspeptic symptoms. A diet low in irritating foods helps reduce dyspeptic symptoms. A diet low in fatty foods helps reduce dyspeptic symptoms.
Navigating the Medical System – Multidisciplinary Collaboration and Periodic Assessments
Navigating the medical system requires constant collaboration with a multidisciplinary team. The team ideally consists of a gastroenterologist. The team ideally consists of an endocrinologist. The team ideally consists of an oncologist. In some cases, the team includes a surgeon. Periodic assessments are indispensable for monitoring tumor progression. Periodic assessments include endoscopy. Periodic assessments include biochemical monitoring. Periodic assessments include imaging. These are indispensable for monitoring therapeutic efficacy. Furthermore, access to updated medical information enhances adherence. Patient involvement in treatment decision-making enhances adherence. This favors an optimal functional prognosis.
In conclusion, Zollinger-Ellison syndrome is a rare endocrine pathology with potentially severe progression, requiring a complex and integrated therapeutic approach. Given its progressive nature, the prognosis is closely linked to early diagnosis, effective control of acid hypersecretion, and appropriate intervention on gastrinomas. In this context, multidisciplinary management, tailored individually and correlated with the disease’s evolutionary stage, becomes essential. By combining pharmacological, surgical, and oncological strategies, complications can be reduced, clinical progression stabilized, and, not least, an optimal functional quality of life for the patient can be maintained in the long term.
References:
- Ito, T., Igarashi, H., & Jensen, R. T. (2012). Zollinger-Ellison syndrome: recent advances and controversies. Current Opinion in Gastroenterology, 28(6), 638-649;
- Metz, D. C., & Jensen, R. T. (2008). Gastrointestinal neuroendocrine tumors: pancreatic endocrine tumors. Gastroenterology, 135(5), 1469-1492;
- Norton, J. A., Foster, D. S., Ito, T., & Jensen, R. T. (2012). Gastrinomas: Medical or Surgical Treatment. Endocrinology and Metabolism Clinics of North America, 41(3), 645-663;
- Zollinger-Ellison syndrome, https://www.mayoclinic.org/diseases-conditions/zollinger-ellison-syndrome/symptoms-causes/syc-20379042.
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