Insulinoma functionally β-cell tumor

　　In functional beta cell tumors of the islet of Langerhans, insulinomas are the most common, accounting for the majority. The tumor often occurs in the body and tail of the pancreas, usually small, mostly less than 2.0 cm. In non-functional cell tumors, it is gastrin-releasing hormone tumor, accounting for a small part, often multiple, and can occur outside the pancreas, commonly seen in the duodenum and gastric wall. Other rare islet cell tumors are glucagonoma, vasoactive intestinal peptide tumor, and somatostatin-releasing inhibitory hormone tumor, etc. Non-functional islet cell tumors are usually very large, even exceeding 10 cm.

　　In addition to general symptoms, functional beta cell tumor of the islet of Langerhans can also cause other diseases. The main manifestation of the disease is elevated serum insulin. In the later stage, due to tumor growth, peripancreatic infiltration, and distant metastasis, it can cause abdominal pain, weight loss, jaundice, and other symptoms.

　　The onset of functional beta cell tumor of the islet of Langerhans is slow, and a few patients are diagnosed only after a long time. If misdiagnosed for a long time, it can cause permanent brain damage. The main clinical manifestations are as follows:

　　I. Whipple triad

　　1. Hypoglycemic symptoms occur after fasting or exercise.

　　2. Blood glucose < 2.8 mmol/L (50 mg/dl) during the attack.

　　3. Immediate relief after injection of glucose.

　　II. Hypoglycemic attacks

　　The frequency of attacks increases with the duration of the disease, the duration of attacks extends, the degree of hypoglycemia worsens, and hypoglycemia can even be induced after meals. It is often accompanied by gradual obesity, pale complexion, dizziness, decreased memory, and decreased reaction ability.

　　There are no effective preventive measures for functional beta cell tumor of the islet of Langerhans. Early detection and early diagnosis are the key to the prevention and treatment of the disease. There is still a possibility of recurrence after tumor resection, and follow-up observation should be carried out. Preventive work should start from the details of life, develop good living habits and dietary habits.

　　When a functional beta cell tumor of the islet of Langerhans attacks, blood glucose is < 2.8 mmol/L (50 mg/dl), and the main clinical examination methods are as follows:

　　1. Serum insulin and C-peptide

　　Plasma insulin and C-peptide levels increase during hypoglycemia, with an insulin index (insulin/blood glucose) > 0.3. If it is > 1.0, the diagnosis can be confirmed. Fasting plasma insulin > 200 uU/ml can also confirm the diagnosis.

　　2. Oral glucose tolerance test

　　Typical cases show a low and flat curve, some may have decreased glucose tolerance, and a few may show early hypoglycemia or normal glucose tolerance curve.

　　3. Fasting glucose test

　　Positive fasting glucose test is helpful for diagnosis. Only those with fasting blood glucose > 2.8 mmol/L can undergo the test, and more than 90% of patients can induce hypoglycemia with fasting for 24-36 hours. A few patients may require fasting for 48-72 hours, and exercise should be added 2 hours before the end of fasting to induce hypoglycemia. Patients who do not induce hypoglycemia after 72 hours of fasting can be excluded from the disease.

　　4. Routine X-ray

　　For gastrinoma patients, the locked meal radiography of the gastrointestinal tract can show multiple and recurrent ulcers in the stomach and duodenum.

　　5. Ultrasound Manifestations

　　The lesion is at the edge or inside the pancreas, round or elliptical, with hypoechoic inside the mass and clear edges. The malignant insulinoma cells have irregular boundaries and uneven internal echoes.

　　6. CT Manifestations

　　The CT manifestations of the scan of isointense masses within the pancreas are mostly small, and can include those buried within the pancreas or locally protruding from the surface of the pancreas. Since functional insulinoma cells are angiogenic and well-vascularized tumors, whether benign or malignant, the mass is significantly enhanced in the early stage of enhanced scanning (hepatic artery phase), presenting as a high-density nodule, higher than the normal pancreas around it. Non-functional tumors are usually larger, with uniform or non-uniform density, and occur more frequently in the body and tail of the pancreas, about 20% showing calcification within the tumor, which can be enhanced after enhancement, with slightly higher density than the normal pancreas, and can appear cystic changes in the center. If there is enlargement of local lymph nodes or involvement or metastasis of adjacent organs, it is a sign of malignant tumor.

　　Patients with insulinoma functional β-cell tumors should mainly eat light foods, pay attention to dietary regularity. Diversify food, ensure balanced nutrition, eat chicken, duck, fish, meat, grains, and legumes, fruits and vegetables, and eat more iron and calcium-rich foods. Try to drink less tea and coffee, as the polyphenols in tea and coffee can inhibit the absorption of iron.

　　The main Western medical treatments for insulinoma functional β-cell tumors are surgical treatment and drug treatment, as follows:

　　1. Surgical Treatment

　　Surgical resection of the tumor; if the tumor cannot be explored during surgery, a subtotal pancreatectomy can be performed.

　　2. Drug Treatment

　　For patients with contraindications to surgery, refusal of surgery, or those whose symptoms do not improve or recur after surgery, dantrolene can be taken, and when combined with diuretics, it can prevent edema. Phenytoin sodium and propranolol also have certain inhibitory effects on insulin secretion; adrenal cortical hormones can also alleviate symptoms. For insulinoma that cannot be removed or has already metastasized, streptozotocin can be used, and half of the patients can achieve remission or prolong survival time. While taking medication, attention should be paid to increasing the number of meals, eating more sugary and fatty foods, and if necessary, adding adrenal cortical hormones to prevent hypoglycemia.