Pancreatic cystadenoma and cystadenocarcinoma
Introduction
Introduction to pancreatic cystadenoma and cystadenocarcinoma Pancreatic cystic tumors include pancreatic cystadenoma and pancreatic cystadenocarcinoma, which are relatively rare. In 1830, Becourt first reported cystadenoma, and in 1911, Kaufman reported cystadenocarcinoma. In recent years, due to the increasing awareness of this disease and the extensive development of imaging examination methods, especially the extensive use of abdominal ultrasound and CT, the diagnostic level of pancreatic diseases has been greatly improved, and reports of pancreatic cystic tumors have gradually increase. basic knowledge The proportion of illness: 0.0003% Susceptible people: no special people Mode of infection: non-infectious Complications: peritonitis, acute pancreatitis, diabetes, gallstones
Cause
Pancreatic cystadenoma and cystadenocarcinoma
(1) Causes of the disease
The etiology of pancreatic cystadenoma is still unclear. It is estimated that the source may have the following aspects: (1) invasion by the ectopic digestive tract primordial cells or the Brunner gland of duodenal aberration; 2 acinar cells originating from the gland; 3 originated from the pancreatic duct epithelium; 4 residual viviparous tissue, while cystic adenocarcinoma may be malignant from mucinous cystadenoma.
(two) pathogenesis
Pancreatic cystic tumor can occur in any part of the pancreas, but it is more common in the tail of the pancreas. The pancreatic cystic tumor covers the epithelial cells because of its cyst wall. Therefore, it belongs to the pancreatic cyst and is considered to be a pancreatic cyst. Species, that is, proliferative or neoplastic cysts, the benign ones are cystadenomas, the malignant ones are cystic adenocarcinomas, the cystadenomas and cystadenocarcinomas are generally similar in appearance, and the tumors are of different sizes, often irregularly rounded. The surface is smooth, the capsule is intact, and there is a clear boundary with the normal pancreatic tissue. There is no obvious adhesion to the adjacent organs and surrounding tissues. The thickness of the tumor wall is uneven. The cystic adenocarcinoma generally does not show invasive growth. The performance may show invasive changes, surrounded by large blood vessels, and involving surrounding tissues and organs, local lymph nodes or liver metastases may occur.
According to the morphology, origin and biological characteristics of cystadenoma, in 1978, Campagno divided it into two types: serous cystadenoma and mucinous cystadenoma. Serous cystadenoma is mainly composed of small capsules, which are composed of most small capsules. The composition is called pancreatic cystic or microcystic cystadenomas. The cut surface is honeycomb-like. The connective tissue space in the capsule divides the cyst into many small cysts of 1~2cm. The endothelium is composed of single-layer flat cells or cubic cells. The cell and its karyotype resemble central acinar cells, so it is called central acinar cystadenoma. The tumor cells have no abnormality, no mitotic figures, smooth inner wall of the cyst without papillary processes, no serous cystadenoma. The tendency of malignant transformation, mucinous cystadenoma is characterized by large cysts and large single-atrial or multi-atrial cysts. The cysts are filled with mucus. The endothelium of the cystic wall is composed of columnar cells. The tumor cells are rich in mucus, but no Glycogen exists, the inner wall of the cyst is smooth or has papillary processes, and mucinous cystadenoma has potential malignant risk. Therefore, mucinous cystadenoma is considered to be a precancerous lesion of mucinous cystadenocarcinoma.
Pancreatic cystadenocarcinoma, also known as mucinous cystadenocarcinoma, originates from the epithelium of the large pancreatic duct or is malignant from a benign cystadenoma of the same origin. The cut surface is a single room or a multi-chamber, and the fluid in the capsule is mucous or Gum-like, can also be brown or bloody and mixed with necrotic tissue. The cyst wall is lined with high columnar epithelial cells and goblet cells that produce mucus. Cells often have dysplasia, mitotic figures are visible, and papillary or cauliflower can be seen on the inner wall of the cyst. In the bulging process, hemorrhagic necrotic areas and calcifications can be seen under the epithelium. The cytoplasm and intracapsular mucus contain a large amount of mucin and no glycogen. In the same capsule, a benign area of normal differentiation and an undifferentiated malignant area can be seen. In cases of adenoma malignancy, a variety of images of cystadenoma, cystadenocarcinoma, and cystadenoma tend to be malignant in the same capsule.
Prevention
Pancreatic cystadenoma and cystadenocarcinoma prevention
If there are reasons for unknown, long-term abdominal distension, pain and discomfort, the attack should be performed for B-ultrasound. If the B-ultrasound is suspected, CT scan should be performed. Early detection, early surgery, and strive to remove the lesion, positive The treatment can improve the cure rate of the disease.
Complication
Pancreatic cystadenoma and cystadenocarcinoma complications Complications, peritonitis, acute pancreatitis, diabetic gallstones
1. Intracapsular hemorrhage infection When cystic tumor cystic necrosis, when infected, there may be a sudden increase in the mass, abdominal pain, fever, but also due to cyst rupture, cystic fluid into the abdominal cavity, the appearance of peritonitis.
2. Acute pancreatitis or diabetic tumor compression or invasion of the main pancreatic duct leads to poor pancreatic drainage. Less than 5% of patients present with acute pancreatitis; tumor destruction of pancreatic parenchyma can lead to endocrine insufficiency, and patients with diabetes or impaired glucose tolerance.
3.10% to 25% of patients with gallstones.
Symptom
Pancreatic cystadenoma and cystic gland cancer symptoms common symptoms abdominal distension abdominal pain abdominal mass nausea liver metastase jaundice
Pancreatic cystadenoma grows slowly, and the general history is long. It has been reported for up to 30 years. The cystadenocarcinoma is often caused by malignant transformation of cystic adenoma. Even the primary cystadenocarcinoma has a longer course than pancreatic cancer. Abdominal pain or dull pain, upper abdominal mass is the main clinical manifestation of pancreatic cystic tumor, followed by weight loss, jaundice, gastrointestinal bleeding, various gastrointestinal symptoms and liver metastasis.
1. Abdominal pain is an early symptom, which may be pain, pain or swelling. The cause of abdominal pain may be that the tumor is gradually enlarged, the intracapsular tension is increased, and the tumor is gradually enlarged to press the stomach, duodenum, and transverse colon. Etc., shifting and appearing symptoms of incomplete obstruction of the digestive tract, in addition to abdominal pain may be associated with loss of appetite, nausea, vomiting, indigestion and weight loss and other symptoms and signs.
2. Abdominal mass is the main symptom and sign. It is often the main reason for patients to see a doctor. It can be the main complaint of the patient or the physical examination. The mass is mostly in the middle of the upper abdomen or the upper left abdomen. The size of the tumor is quite different. Can only be touched, the larger can occupy the entire abdominal cavity, the tumor is deep or oval, the texture is tough, the huge mass has a cystic feeling, generally no tenderness, a few cystic tumors located in the head of the pancreas, due to cysts Compression of the common bile duct and jaundice, when the tumor compresses the splenic vein or invades the splenic vein, it can cause embolism, which is characterized by enlarged spleen, and can cause varicose veins in the fundus and lower esophagus, and even hematemesis. In some cases, the tumor can be Invasion of the stomach, duodenum, transverse colon, and ulceration into the digestive tract cause rare gastrointestinal bleeding.
3. Liver metastasis Some patients have intrahepatic metastatic lesions on the basis of pancreatic cysts, which are characterized by the presence of single or multiple cystic masses in the liver.
Examine
Examination of pancreatic cystadenoma and cystadenocarcinoma
1. Serum tumor marker cystic adenocarcinoma patients with serum CA1-9-9 may be significantly elevated, decreased after surgical resection, tumor recurrence, metastasis, can be increased again, CAl9-9 can be used as an indicator of postoperative recurrence of cystadenocarcinoma, capsule In patients with adenoma, blood CEA and CAl9-9 are basically normal.
2. Cyst fluid analysis preoperative or intraoperative aspiration of cystic fluid for enzymology, cancer labeling and cytology examination have differential diagnostic value, access to cystic fluid by B-guided percutaneous fine needle aspiration, intraoperative puncture suction At the time of ERCP, duodenal puncture and laparoscopy were performed and puncture was performed.
(1) Cytological examination: This method is of great value in the diagnosis of mucinous tumors. If mucus or mucous cells containing glycogen are observed in the sac smear, the mucinous cystic tumor is diagnosed and the sensitivity of the mucinous cystadenoma is diagnosed. 54% to 87%, mucinous cystadenocarcinoma 50% to 75%, found that malignant tumor cells are diagnosed, because the tumor may only be local malignant, no positive findings can not rule out cystadenocarcinoma, about 60% of serous cystadenoma The cystic tumor cyst fluid with degenerative changes may not have detached epithelial cells. Therefore, pseudocysts and cystic tumors cannot be identified when the cyst fluid is inflammatory and there is no epithelial cells.
(2) Amylase: The amylase of pseudocyst is elevated. The cystic tumor is generally not connected with the main pancreatic duct. The amylase of the cystic fluid is not elevated, which has certain differential significance. However, when the cystic cavity of the tumor is connected with the pancreatic duct When the cystic amylase can be elevated, Lewandrowski et al reported cystic amylase, pseudocyst is 543 ~ 36610U / L, cystic tumor is 44 ~ 34400 U / L, of which 43% amylase level and pseudocyst There is overlap, only when the amylase is very low, it may indicate cystic tumors, so it is not reliable to identify pseudocysts and cystic tumors according to cystic amylase.
(3) Carbohydrate antigen: The tumor marker in the cyst fluid is different from the tumor marker in serum, which is characterized by a significant increase in specificity. Polysaccharide antigens such as CEA, CAAl5.3-CA72-4-CAl25 in the 20th century In the mid-1980s, there were many studies. The CEA level of cystic fluid reported by Pinto et al. was 22 ng/ml for mucinous cystadenoma and 141 ng/ml for mucinous cystadenocarcinoma, which was significantly higher than that of pseudocyst 3.2 ng/ml and serous sac. Adenoma 8.2 ng/ml; Lewandrowski believes that when CEA>26ng/ml, it is suggestive of mucinous tumor, but can not identify benign and malignant, this is not important, because mucinous cystadenoma and cystadenocarcinoma need to be removed, The value of CAl5.3-CA72-4 in identifying mucinous cystadenocarcinoma is better than CEA, CAl5.3>70U/L, the specificity of diagnosis of cystadenocarcinoma can reach 100%, CA72-4>70U/L, cystadenocarcinoma That can be distinguished from cystadenoma and pseudocysts. When CA72-4>150U/L, the specificity and sensitivity of diagnosis of cystadenocarcinoma can reach 100%.
(4) Relative viscosity (RV): Lewandrowski used a quantitative viscosity meter (Ostwald viscosity meter) to measure the RV of the cyst fluid, compared with normal plasma RV (1.4 to 1.8). The results showed that when the RV>1.63, the mucinous cyst was diagnosed. The sensitivity is 89%, the specificity is 100%; if RV <1.63, strongly suggesting non-mucinous cysts, the biggest advantage of this method is that it is rapid and suitable for intraoperative use.
3. Pancreatic juice K-ras gene mutation analysis Semi-quantitative PCR method was used to detect K-ras gene mutation in pancreatic juice, and 43% of cystic tumors were positive.
4. Abdominal plain film 10% to 18% of these diseases have fine calcification, abdominal X-ray scan often found calcification of the tumor wall, it is estimated that about 10% of patients with pancreatic serous cysts have tumor calcification on the X-ray film, serum Cystic adenomas have a higher calcification rate than mucinous cystadenoma. Serous cystadenomas often show central, linear or arcuate calcification, and 10% of them are located in central stellate scars. Radial pattern, once this characteristic manifestation occurs, can basically be diagnosed, mucinous cystadenoma mostly manifests as peripheral calcification.
5. Ultrasound is superior to CT in showing the internal structure of the tumor, the separation and the neoplasm.
(1) serous cystadenoma: cysts and parenchymal mixture are often shown on the sonogram. When the tumor is composed of a large number of very small cysts (<2mm), it is still homogeneous and solid; if the cyst is large (5 ~20mm), it is multi-atrial, each room is closely connected with a honeycomb-like structure, Fugazzola et al believe that if the ultrasound or CT shows a honeycomb-like pattern can be diagnosed as serous cystadenoma; central strong echo with sound and shadow , it suggests calcification.
(2) mucinous cystadenoma and cystadenocarcinoma: can be expressed as single or multi-room, but the size of each room is relatively large, often with posterior wall enhancement effect, sometimes large and irregular in the room. Papillary neoplasms protrude into the sac from the wall of the capsule.
6. CT is superior to ultrasound in showing calcification, position, wall thickness and blood circulation of pancreatic cyst. According to the connective tissue content of tumor on plain CT, the density is between water and muscle, but serous cystadenoma often It is shown as a homogeneous low-density mass with a CT value of 10 to 16 Hu, which may be lobulated, sometimes with calcification and star-shaped calcification. Because of the abundant capillary network in the serous cystadenoma, it is enhanced. After scanning, it is often seen that the tumor is diffusely homogenous or locally enhanced, the boundary is clear and the honeycomb-like or radiation-interlaced intervals are shown. Warshaw found that only 50% of serous cystadenoma showed multiple findings on CT. Small cysts, and star-shaped calcification only accounted for 11% of patients, mucinous cystadenoma CT scan often showed a larger single-wall thick-walled cyst, its density is close to water, the boundary is clear, sometimes visible in the capsule Or a thin, thin separation can also occur in the form of a multi-capsule, and can be seen as a low-density neoplasm growing from the wall of the capsule into the cavity. On the larger wall, an ascus can be seen along the wall of the capsule, enhancing scanning, especially Dynamic high-dose angiography, See wall, neoplasms, and are reinforced by capsule interval, mucinous cystadenocarcinoma with mucinous cystadenoma, but tumor invasion and metastasis.
7. MRI serous cystadenomas show nodular borders around the mass on MRI, especially on T2-weighted images, which may be due to T2-weighted images between normal pancreas and intracapsular fluids. Large contrast (liquid T2 relaxation time is longer than normal pancreas), the tumor can be separated, the tumor shows a uniform low density on the T1-weighted image, and the uniform high density on the T2-weighted image, the mucous sac Adenoma or cystadenocarcinoma presents a round or irregular elliptical mass with internal separation; and the resolution is higher than CT, and the density of each room constituting the tumor is different between T1 and T2 weighted images. It can also be seen that large papillary sputum organisms protrude into the sac, and the cause of the density difference between the rooms may be related to the intracapsular hemorrhage, the protein content in the sac fluid, the ratio between the solid components of the tumor, and the like. Performance, but helpful for identification.
8. Angiography serous cystadenoma is rich in vascular network. Therefore, the contrast film can be expressed as a large nourishing blood vessel supplied by the abdominal or mesenteric blood vessels, drainage vein, homogeneous tumor staining and occasional arteriovenous shunt. Mucinous cystadenoma often presents as an avascular zone surrounded by blood vessels, which is mainly related to the cystic component of such tumors, with mild tumor staining and small neovascularization in the wall or nipple. Area, the appearance of the arterial sheath is considered to be a manifestation of malignant tumors, whether it is serous cystic adenoma or mucinous cystadenoma can cause displacement of the splenic vein, compression and obstruction.
Diagnosis
Diagnosis and differentiation of pancreatic cystadenoma and cystadenocarcinoma
Because the disease is very rare in the clinic, the symptoms are not typical, the course of disease progresses slowly, the appearance of the tumor often resembles benign lesions, and the pathology often cannot be quasi-deterministic due to its special structure, so it often leads to misdiagnosis and mistreatment, when encountering the above clinical manifestations At the time, it should be further examined whether the mass is located in the pancreas and is cystic. The biochemical examination and imaging examination for the diagnosis of pancreatic diseases are of certain value for diagnosis.
Differential diagnosis
1. Pancreatic pseudocyst pseudocyst, especially atypical, because it contains clots, necrotic tissue or peripheral calcification plus uneven wall thickness, it is difficult to distinguish from mucinous cystadenoma, but pseudocyst is retrograde Pancreatic ductography (ERCP) is more common in cysts connected to the main pancreatic duct (60% to 65%), while cystic tumors are less connected (<30%). Pseudocysts often show chronic pancreatitis in ERCP. Changes in the pancreatic duct, CT often appear as a smooth thin-walled cyst, the enhancement of the wall and the actual components are not enhanced, the calcification point is visible in the pancreas outside the lesion, and the vascular area shows avascular area, except for the above imaging identification. A typical history of pancreatitis or history of trauma and intraoperative specific findings are also helpful in differential diagnosis.
2. The retention cyst is caused by compression or obstruction of the main pancreatic duct. It is a homogeneous, well-defined thin-walled cyst. CT and ERCP often find evidence of chronic pancreatitis obstructing the solid tumor of the pancreatic duct or causing obstruction of the pancreatic duct. .
3. Mucinous pancreatic duct dilatation is a branch cystic dilatation of the pancreatic duct. It is similar to polycystic cystadenomas in CT findings; however, it belongs to intraductal lesions. This type of tumor has the following characteristics for identification. :
1 CT scan was a polycystic mass; it showed dilatation of the main pancreatic duct after obstruction.
2 Endoscopy showed that the mucus was discharged from the main nipple, and ERCP showed a filling defect in the dilated pancreatic duct.
3 The tumor is located in the uncinate part of the pancreas.
4. Non-functional islet cell tumor and leiomyosarcoma When there is necrosis in the center, there may be a single room or even a multi-atrial thick-wall cyst, and there may be calcification, but the contrast of these tumors is much higher than that of the pancreatic sac. Sexual tumors, when it is difficult to distinguish from cystadenomas, need to combine needle aspiration or intraoperative biopsy.
5. Papillary cystic tumors are rare, almost all occur in young women, can be differentiated from cystadenoma, imaging has a clear boundary, internal structure is cystic mixed or thick-walled cyst, in the capsule or wall It can be seen that calcification, Ohtomo et al found that the fibrous sac and the intracapsular hemorrhage on the edge of the tumor on MRI are considered to have certain diagnostic significance.
