What Is a Gastrinoma?

Gastrinoma is a gastrointestinal pancreatic neuroendocrine tumor. It is characterized by refractory, recurrent or atypical sites of peptic ulcer and high gastric acid secretion. It is also called Zhuo-Ai syndrome. The cause of gastrinoma is unknown and may originate from ₁ cells in the pancreas. Because gastrinoma is more common in pancreatic tissue, less common in other tissues outside the pancreas, and the tumor is small, it is sometimes difficult to accurately locate the tumor. Positioning creates good conditions. If there is no distant metastasis, the tumor can be cured after resection. The disease is relatively rare, and the age of onset is mostly between 30 and 50 years old, with a male to female ratio of 3: 2 to 2: 1.

Basic Information

nickname: Zhuo-Ai syndrome
English name: gastrinoma
Visiting department: Oncology
Multiple groups: 30 to 50 years old

Common locations: Pancreatic tissue
Common causes: The etiology is unknown and may originate from 1 cells of the pancreas.
Common symptoms: Abdominal pain, diarrhea, multiple endocrine adenoma disease.
Contagious: no

Causes of Gastrinoma

The cause of gastrinoma is unknown and may originate from ₁ cells in the pancreas.

Gastrinoma clinical manifestations

Although gastrinoma is mostly malignant, because the tumor is small and develops slowly, the tumor itself rarely causes obvious symptoms. In the late stage of the disease, the symptoms of malignant tumor infiltration appear. Its clinical manifestations are mainly related to a large amount of gastric acid secretion.

Abdominal pain

Due to peptic ulcers, there may be a family history of peptic ulcers. This is due to the strong and continuous stimulation of gastrin, which causes the gastric mucosa to be secreted in large quantities. The ulcer is usually single or multiple, and the diameter is usually <1 cm, and a few can be> 2 cm.

Diarrhea

Patients may be accompanied by diarrhea. In some cases, diarrhea can occur when the ulcer develops, and may be the first symptom or the sole symptom of the disease. A few patients have diarrhea without ulcers. Diarrhea is often massive, watery, and fatty. 10 to 30 times a day. In severe cases, water and electrolyte disorders can occur, and symptoms such as dehydration, hypokalemia, and metabolic acidosis can occur.

3. Multiple endocrine adenoma disease

Some patients may be complicated by other endocrine tumors. The distribution of the endocrine glands involved is the parathyroid glands, pancreas, pituitary, adrenal gland, and thyroid. Corresponding clinical manifestations related to hyperendocrine function appear.

Gastrinoma test

Gastrin determination

The most sensitive and specific test for diagnosing gastrinoma is to determine the serum gastrin concentration. Gastrinoma patients often have fasting serum gastrin levels of> 150 pg / ml, with average levels approaching 1000 pg / ml. In patients with clinical peptic ulcer symptoms and high gastric acid secretion, the diagnosis of gastrinoma can be established when the fasting serum gastrin concentration is significantly increased (> 1000 pg / ml).

2. X-ray barium meal inspection

Abnormal radiographic images are of certain value in diagnosing gastrinoma. Gastric folds often show prominently and the stomach contains a large amount of fluid. Mucosal folds of the entire duodenum and part of the jejunum thicken and widen. Separately, there is a large amount of liquid in the small intestine cavity, causing irregular flocculent precipitation of barium. Barium meal examination of the upper gastrointestinal tract generally does not reveal pancreatic gastrinoma, but tumors protruding from the duodenal wall are often found.

3. Excitation test

(1) Secretin stimulation test is the most valuable stimulation test to judge patients with gastrinoma. After intravenous injection of secretin, more than 95% of gastrin tumors have a positive reaction, and false positives in this test are rare.

(2) Calcium challenge test 80% of gastrinoma patients showed increased gastrin release after calcium infusion, and the concentration of most gastrinoma patients increased significantly (increased amount> 400pg / L), the highest gastrin Concentrations of voxel are usually reached at the beginning of the injection. Calcium challenge test is less sensitive and specific than the secretin challenge test. If gastrinoma patients do not respond positively to the secretin challenge test, they generally do not respond to the calcium challenge test.

(3) Standard meal stimulus test The standard meal includes 1 slice of bread, 200ml milk, 1 boiled egg, 50g cheese (including 20g fat, 30g protein, 25g sugar), 15 minutes before ingestion, 0 minutes, and every 1 minute after ingestion. The blood gastrin values were measured at 10 minutes, and were taken until 90 minutes after ingestion. These checks should be completed before starting any challenge test (such as a secretin challenge test). If hypergastrinemia is caused by gastric acid deficiency or hypoacidity, no further examination of gastrinoma is necessary.

Gastrinoma diagnosis

The following conditions can highly suggest the diagnosis of gastrinoma: ulcers at the distal end of the duodenum; multiple ulcers of the upper gastrointestinal tract; usual ulcer treatment is ineffective; ulcers recur quickly after surgery; Or difficult to explain the cause of diarrhea; patients with a typical family history of peptic ulcers; patients with a history of parathyroid or pituitary tumors or related family history; patients with peptic ulcers with urinary stones; no history of taking nonsteroidal anti-inflammatory drugs Helicobacter pylori-negative peptic ulcer; with high gastric acid secretion or hypergastrinemia or both.

Gastrinoma differential diagnosis

1. Peptic ulcers are more common in a single ulcer or in the stomach and duodenum (complex ulcers), and multiple gastric or duodenal ulcers are relatively rare.

2. The similarities between gastric cancer and gastrinoma are poor medical treatment and intra-abdominal metastases, but gastric cancer rarely has duodenal ulcers, and there is no high gastric acid and high gastrin secretion characteristics. Histopathological examination of gastroscopy Has differential diagnostic value.

Gastrinoma complications

Patients may have gastrointestinal bleeding, perforation of ulcer disease. It is not uncommon to have other endocrine tumors.

Gastrinoma Treatment

The advent of H2 receptor blockers and proton pump inhibitors has greatly reduced the incidence and mortality of peptic ulcer combined with this disease, thereby effectively avoiding total gastrectomy. Now, the biggest threat to life of gastrinoma is not concurrent ulcers but invasion of malignant tumors. The treatment goals of gastrinoma patients are to control ulcers, prevent complications and control tumor development.

Medical treatment

The main purpose of medical treatment of gastrinoma patients is to reduce clinical symptoms, inhibit gastric acid secretion and prevent peptic ulcer. All patients with gastrinoma should titrate their gastric acid concentration periodically to determine the amount of antacids, and should achieve a reduction in gastric acid secretion to less than 10 mmol / h before the next dose.

(1) Proton pump inhibitors Proton pump inhibitors Omeprazole, lansoprazole, pantoprazole, rabeprazole, and esomeprazole are irreversibly bound to the H + -K + ATPase of parietal cells Effectively inhibit gastric acid secretion, its effect can last more than 24 hours, and many patients can be administered once a day.

(2) H2 receptor antagonists H2 receptor antagonists can relieve symptoms, reduce acid secretion and heal ulcers. Cimetidine is the first proven H2 receptor antagonist to cure ulcers in 80% to 85% of gastrinoma patients. Ranitidine and famotidine are equally effective. The combination of H2 receptor antagonists and anticholinergic drugs can increase the effect of H2 receptor antagonists in reducing gastric acid secretion.

(3) Octreotide reduces gastric acid secretion by directly inhibiting the release of parietal cells and gastrin. The synthetic octreotide analogue has a half-life of 2 hours and can be injected subcutaneously. It can reduce serum gastrin concentration for 16 hours and reduce gastric acid secretion for 18 hours. Its long-term application is not superior to omeprazole, but it can be used for short-term gastrin treatment with antacids requiring parenteral administration Tumor patients.

2. Surgical treatment

Surgical removal of gastrinoma is the best treatment method. The goal of treatment is to completely remove the tumor by surgery, eliminate high gastrin secretion, high gastric acid secretion and peptic ulcer, and protect patients from malignant tumors.

3. chemotherapy

There are different chemotherapy regimens for malignant gastrinoma, including streptozotocin (streptozotocin), streptozotocin (streptozotocin) plus 5-fluorouracil, or a combination of both plus doxorubicin. Chemotherapy cannot reduce gastric acid secretion, but has certain effects on reducing tumor volume and reducing symptoms caused by tumor mass compression or invasion. Chemotherapy does not improve survival rate. At present, it is believed that interferon can stop tumor growth in 25% of patients with metastatic gastrinoma, but it cannot reduce tumor volume and improve survival rate.

Gastrinoma prognosis

The general application of acid and anticholinergic drugs can only achieve temporary curative effects, and it is difficult to completely cure the disease.