Genuine pancreatic cysts

　　Genuine pancreatic cysts occur within the pancreas and are relatively rare. The etiology mainly includes the following aspects:

　　1. Congenital cysts

　　Commonly seen in children, caused by developmental abnormalities of the pancreatic duct and acinar cells. This includes solitary or multiple small cysts within the pancreas, dermoid cysts, congenital multicystic diseases involving the pancreas and other organs, and cystic fibrosis, a genetic systemic disease with abnormal mucus gland secretion.

　　2. Retention cysts

　　It is a relatively common genuine cyst in clinical practice, caused by various reasons leading to poor drainage of the pancreatic duct, resulting in retention of pancreatic juice. Common causes include pancreatic duct stones, parasites, tumors, or scarring contraction around the pancreas, as well as stenosis or obstruction of the pancreatic duct due to tumor compression, etc.

　　3. Degenerative cysts

　　Secondary to bleeding or necrotic changes within the pancreas.

　　4. Parasitic cysts

　　Commonly caused by echinococcus or porcine cysticercosis, etc.

　　5. Benign cysts

　　Caused by abnormal hyperplasia of pancreatic epithelial cells or acinar cells, common ones include pancreatic cystadenoma, cystadenocarcinoma, and cystic teratoma, etc.

　　Some genuine pancreatic cysts are relatively small in size and may not show any symptoms, while larger cysts can produce more obvious symptoms. The diseases they can cause mainly include the following aspects:

　　1. Secondary infection

　　Patients may present with symptoms such as chills, fever, elevated white blood cells, and toxic blood signs. The mass in the upper abdomen may have significant tenderness. An increase in intracystic pressure can cause the cyst to rupture and bleed, which requires high attention. Treatment should include the active use of large doses of combined antibiotics, as well as surgery, such as external drainage. In recent years, with the development of interventional radiology technology, percutaneous cyst puncture drainage can be performed under the guidance of B-ultrasound or CT, which can drain the pus within the cyst and can also be used to flush the intracystic space with antimicrobial drugs through the drainage tube, achieving good results.

　　2. Cyst rupture

　　Cysts can rupture due to changes in intracystic pressure or the effect of external forces. It manifests as sudden severe upper abdominal pain, and the cyst becomes significantly smaller or disappears, with signs of acute peritonitis, and abdominal puncture can extract a fluid rich in amylase. Due to the corrosive and infectious effects of the cyst fluid, cysts can spontaneously penetrate the digestive tract, forming fistulas, such as cyst-colon fistulas, and some may lead to gastrointestinal bleeding. Cyst rupture is a serious complication, and once it occurs, it should be surgically drained as soon as possible.

　　3. Hemorrhage

　　Hemorrhage from a cyst is a serious complication that directly threatens the patient's life. There are many large artery vessels in the upper abdomen and around the pancreas, such as the left gastric artery, right gastric artery, splenic artery, and splenic vein. Due to infection, compression, and erosion by pancreatic enzymes, these large vessels can rupture and hemorrhage, at which time the patient may suddenly experience upper abdominal pain, pale complexion, increased heart rate, and decreased blood pressure, among other symptoms of shock. At the same time, the abdominal mass may become significantly larger. If the patient has undergone cyst external drainage, a large amount of fresh blood may be seen in the drain. This complication has a rapid course and should be explored urgently, with hemostasis or resection of the involved organs according to the bleeding situation.

　　4. Other complications

　　If the cyst has a minor rupture, it can form pancreatic ascites, and some patients may also have pleural effusion. Cysts in the head of the pancreas that compress the lower end of the common bile duct can cause obstructive jaundice; cysts that compress the portal venous system can cause portal hypertension; hyperglycemia can occur when islet function declines.

　　The clinical manifestations of pancreatic cysts are related to the type, size, location of the cyst, and the stage of the primary disease. Some cysts are small and may not show any symptoms, while larger cysts can produce more obvious symptoms.

　　1. Symptoms caused by cysts

　　Abdominal fullness and discomfort, as well as pain in the upper abdomen, are important symptoms of pancreatic cysts, which are often radiated to the left shoulder and lower back. They are mostly persistent dull or aching pain, which can also occur as intermittent colicky pain. If the cyst bleeds or becomes infected within the cyst, pain can also occur. Acute severe pain may occur when combined with cholelithiasis.

　　2. Symptoms of compressing surrounding organs

　　If the cyst is located in the head of the pancreas, it can compress the lower end of the common bile duct, causing obstructive jaundice; compressing the duodenum or gastric antrum can cause complete or incomplete pyloric obstruction; compressing the inferior vena cava can cause lower limb edema or superficial varicose veins; compressing the kidney or ureter can cause urinary tract obstruction and hydronephrosis; compressing the portal venous system can cause ascites or portal hypertension.

　　3. Consumptive symptoms

　　Gastrointestinal dysfunction caused by the cyst, as well as the aversion to eating that can occur after meals due to increased pain, can all lead to significant weight loss and weight reduction. In addition, insufficient exocrine pancreatic function can cause fat digestion disorders, resulting in steatorrhea.

　　4. Complications of cysts

　　Infection of a cyst can lead to symptoms such as chills and fever, even sepsis; if there is acute hemorrhage within the cyst, it can manifest as rapid enlargement of the cyst and shock symptoms; if the cyst ruptures, symptoms of acute peritonitis may occur.

　　During physical examination, an upper abdominal mass is the most common positive sign of pancreatic cysts, and most patients can feel a mass in the abdomen. Generally located in the midline or slightly to the left of the upper abdomen, the size varies, round or elliptical, smooth surface, showing cystic sensation, with tension, some with clear boundaries and varying degrees of tenderness, not moving with respiration. In addition, patients with chronic cysts are often quite thin. If the cyst compresses the lower end of the common bile duct, jaundice of varying degrees may occur.

　　Since true pancreatic cysts often occur secondary to acute pancreatitis and pancreatic injury, about 3/4 of patients are caused by acute pancreatitis, and about 10% of acute pancreatitis cases may develop pseudopancreatic cysts. The key to preventing this disease is to make an early diagnosis of acute pancreatitis or pancreatic injury and take appropriate treatment measures early. Once diagnosed, surgery should be scheduled. It is advisable to avoid overeating and drinking in daily life, and if there is cholecystitis, it should be treated actively to reduce the recurrence of pancreatic cysts.

　　In blood routine examination, true pancreatic cysts may show an increase in white blood cells, especially明显 more obvious in secondary infection. Sometimes blood sugar may also increase, and urine sugar may be positive, which is an indication of insufficient islet function. The presence of oil droplets in the stool indicates insufficient exocrine pancreatic function. In cyst cases, serum trypsinogen and plasma antithrombin levels are often significantly elevated, which is helpful for early diagnosis of pancreatic cysts.

　　1. X-ray examination

　　1. Abdominal plain film: For large cysts, abdominal plain film can show soft tissue mass shadows. A few patients may show calcification shadows of the pancreas or cyst, which appear as patchy and are caused by pancreatic calculi or calcification due to pancreatitis. The calcification of the cyst wall appears as an arc-shaped dense line shadow, which can be used to show the position, size, and shape of the cyst. A few cases may show elevation of the left diaphragm, and those with pleural effusion may show blurred costodiaphragmatic angle. Secondary infection of the cyst can form an abscess, which may show saponaceous gas shadows.

　　2. Gastrointestinal barium contrast: This includes two methods, upper gastrointestinal barium meal and barium enema, and about 80% of cases show positive findings. The main manifestations are compression and displacement of the cyst on the stomach, followed by compression and displacement of the duodenum, duodenojejunal flexure, transverse colon, splenic flexure of the colon, and descending colon. Based on this, the position, size, shape, and relationship of the cyst to the pancreas can be indirectly judged. Generally, a correct diagnosis can be made except for very small cysts or those far from the pancreas.

　　3. Pancreatic ductography: There are many methods for pancreatic ductography, including endoscopic retrograde cholangiopancreatography (ERCP), intraoperative pancreatic ductography (OPT), pancreatic ductography through drainage tubes, and percutaneous transhepatic cholangiography (PFC). ERCP can only show signs of compression, displacement, and stenosis of the pancreatic duct, as well as whether the cyst communicates with the pancreatic duct, but cannot provide more signs for the diagnosis of the cyst. OPT has been increasingly used in recent years and is mainly used for the diagnosis of small pancreatic cysts within the pancreas.

　　4. Angiography: Selective angiography of the celiac artery and superior mesenteric artery can show compression, displacement, and a vascular 'hugging ball' sign around the cyst, with sparse and straightened blood vessels. The absence of blood vessels within the cyst is a characteristic feature.

　　II. Ultrasound examination

　　Ultrasound is the most commonly used and preferred examination method in clinical practice, with a diagnostic accuracy of up to 90% for pancreatic cysts. Ultrasound can detect the location, size, thickness of the cyst wall, and the number of cysts in the pancreas. Larger cysts often compress surrounding tissues, causing them to be compressed and displaced.

　　III. CT examination

　　CT can accurately display the location, size of the pancreatic cyst, measure the thickness of the cyst wall, the density of the cyst contents, detect the presence of intracystic septa or new growths, understand the relationship between the cyst and surrounding organs and important blood vessels, and provide sufficient reference information for diagnosis and treatment. Especially for patients with obesity or gastrointestinal bloating, for whom B-ultrasound cannot make an accurate diagnosis, CT shows its superiority.

　　IV. Puncture biopsy under the guidance of ultrasound or CT

　　After the diagnosis of pancreatic cysts is basically clear, it is necessary to differentiate the nature of the cyst. Relying solely on imaging technology is often difficult to make a distinction, while percutaneous biopsy of pancreatic cysts can provide powerful assistance for differential diagnosis. Under the guidance of ultrasound or CT, the puncture site is selected, the needle insertion direction and depth are determined, which can maximize the avoidance of damage to surrounding organs and large blood vessels, and serious complications generally do not occur. Through percutaneous biopsy, the tissue of the cyst wall and the cyst fluid can be obtained for histopathological examination, and the detection of amylase, tumor markers, cyst fluid cytology, and cyst fluid viscosity in the cyst fluid can help differentiate the nature of the pancreatic cyst.

　　Patients with true pancreatic cysts should eat light, reasonably balanced meals, and pay attention to adequate nutrition. It is advisable to eat high-protein, nutritious, vitamin and mineral-rich, high-calorie, easy-to-digest foods, and to avoid greasy, difficult-to-digest, fried, smoked, grilled, cold,刺激性食物, and high-salt, high-fat foods. Spicy foods and alcohol should be avoided.

　　The treatment method for pancreatic cysts must be determined according to their type, nature, location, size, and the different stages of development of the cyst. Generally, it can be divided into non-surgical treatment and surgical treatment. In recent years, with the development of imaging and endoscopic techniques, some new treatment methods for pancreatic cysts have emerged.

　　I. Non-surgical treatment

　　Applicable to the early stage of small cysts or acute pseudopancreatic cysts. For pancreatic cysts treated without surgery, close follow-up of the cyst should be carried out using methods such as ultrasound or CT. If the cyst increases and does not absorb, produces obvious clinical symptoms, or complications such as infection, rupture, or hemorrhage occur, active surgery should be considered.

　　II. Surgical treatment

　　Surgical treatment is the main method for the treatment of pancreatic cysts, suitable for pseudopancreatic cysts with clinical symptoms or complications after non-surgical treatment, large true cysts, and various types of pancreatic cystic tumors.

　　1. Operation timing: For large true cysts with clinical symptoms but without complications, surgery can be scheduled. Some scholars divide the timing of surgery into three categories: emergency surgery, early surgery, and elective surgery, which we believe is quite reasonable.

　　(1) Emergency Surgery: Suitable for acute complications that threaten life, such as cyst rupture, hemorrhage, secondary infection causing cyst formation, etc.

　　(2) Early Surgery: Suitable for cysts that produce severe symptoms, such as severe abdominal pain, fever, symptoms caused by mass compression such as jaundice, dyspnea, pyloric stenosis, etc. Suspected pancreatic cystic tumors.

　　(3) Elective Surgery: Suitable for cysts that have no response to non-surgical treatment, with no complications but with clinical symptoms. Generally, surgery within 2 to 4 months after onset is preferable, at which time the cyst wall is thicker, and the success rate of various internal drainage surgeries is higher.

　　2. Surgical Methods: There are many surgical methods for pancreatic cysts, and the specific surgical method for the patient should be determined according to the type, nature, location, size of the cyst, as well as the patient's condition, the degree of adhesion and maturity of the cyst, and the technical conditions of the surgical hospital, among other specific circumstances. Common surgical methods include cystectomy, cyst internal drainage, and cyst external drainage.

　　(1) Cystectomy: Suitable for true cysts with a small volume and intact capsule located in the body and tail of the pancreas. For cysts suspected to be pancreatic cystic tumors, even if located in the head of the pancreas, the surgery is more difficult, but it should be removed as much as possible.

　　(2) Cyst Internal Drainage: Suitable for pseudopancreatic cysts or larger solitary true cysts. This involves anastomosing the cyst with the jejunum, or the stomach, duodenum, to drain the cyst contents into the digestive tract, causing the cyst to gradually collapse and atrophy, with granulation tissue proliferation, which is eventually filled with fibrous tissue, making the cyst cavity disappear and the anastomotic site also close. Generally, surgery is advisable 6 weeks after cyst formation, at which time the cyst wall is mature and thick, making anastomotic fistula less likely. The anastomosis can be chosen according to the location and size of the cyst, with anastomosis with the stomach, duodenum, or jejunum. The anastomotic orifice should be placed at the lowest part of the cyst, and the diameter should be sufficient, generally around 5 cm, to prevent anastomotic stricture. A routine pathological examination of the cyst wall tissue should be performed before anastomosis to exclude the possibility of pancreatic cystic tumors. Practice has proven that the Rouxen-Y anastomosis between the cyst and the jejunum is effective, as it can both drain the cyst and prevent the reflux of gastrointestinal contents, and has been widely used.

　　(3) Cyst External Drainage: Also known as cyst bagging surgery, it is a relatively traditional treatment method. External drainage involves directly draining the contents of the cyst to outside the peritoneal cavity, which can cause significant loss of water, electrolytes, proteins, and pancreatic enzymes after surgery. It also has a considerable stimulating or corrosive effect on local skin, resulting in certain damage to both the whole body and the local area. Furthermore, it often leads to the formation of long-lasting fistulas or recurrence of cysts after surgery, making postoperative management quite difficult. Therefore, it is used less frequently nowadays. It is only used for cases with secondary infection of the cyst, poor patient condition, and inability to tolerate other surgeries; or for cases where the cyst wall is fragile and widely adherent, making internal drainage impossible. This surgery involves making a cut in the cyst wall and间断缝合 with the peritoneum, forming the cyst into a bag shape, with the bag opening communicating with the outside world, and gauze packing the cyst cavity. External drainage can be divided into one-stage and two-stage procedures. One-stage involves directly suturing the cyst wall to the abdominal wall after making the cut, forming an outward bag-shaped opening; two-stage involves not cutting the cyst wall first, but suturing the cyst wall to the abdominal wall, waiting for 3 to 5 days for the cyst wall and abdominal wall to form adhesions, and then cutting the cyst wall and draining the cyst cavity. One-stage surgery is more convenient and practical than two-stage surgery.

　　3. Application of New Technologies In recent years, with the development and application of interventional radiology and endoscopy, some patients with pancreatic cysts can avoid laparotomy surgery and achieve the purpose of internal or external drainage through puncture and catheter placement techniques under the guidance of ultrasound or CT, or endoscopic anastomosis techniques.

　　(1) Percutaneous Catheter Drainage: Suitable for infectious or non-infectious cysts. Under the guidance of ultrasound or CT, puncture the cyst at a location avoiding internal organs or blood vessels, insert a guide wire into the cyst after aspirating the cyst fluid to confirm entry into the cyst, withdraw the puncture needle, and insert a catheter into the cyst cavity along the guide wire. After confirming the appropriate position of the catheter with ultrasound or CT, withdraw the guide wire, fix the catheter, and the external drainage is completed. The general drainage time is 2-4 weeks. When there is no fluid discharge from the drainage tube, and ultrasound or CT confirms that the cyst has disappeared or significantly reduced, it is proven that the drainage is successful, and the drainage tube can be removed. This method has minimal injury, short operation time, wide indications, and an efficiency rate of more than 70%. For cysts that cannot be completely absorbed, it can also improve symptoms and is conducive to further surgical treatment.

　　(2) Endoscopic Drainage: Suitable for patients with cysts adhering closely to the stomach or duodenum. The method is to puncture the wall of the stomach or duodenum and the cyst under an endoscope using a hot needle or laser, and then place a nasogastric tube into the cyst for continuous drainage. Alternatively, use a special endoscopic anastomosis stapler to anastomose the cyst with the stomach or duodenum.