[The role of matrix metalloproteinases and their inhibitors in pathogenesis of pancreatic pseudocysts]

The investigation was conducted in 47 patients, operated on for pancreatic pseudocysts (PP). Activity of matrix metalloproteinases (MMP-9) and content of their tissue inhibitor (TIMP-2) were determined in the blood serum for estimation of inflammatory factors, hypoxia severity and state of the pancreatic tissue reconstruction. High activity of MMP-9 and TIMP-2 in presence of PP types I and II was noted in patients, what, probably, is caused by compensation reaction, directed towards inhibition of the collagen system destruction (predominantly of collagen type IV) and prevention of further reconstruction of pancreatic connective tissue. While progressing of pancreatic fibrosis the MMP-9 activity and the TIMP-2 level have lowered in comparison with these indices while its absence. In PP type III the MMP-9 activity was by 83.6% higher, than in a control group, but, by 51.4 and 35.1% lower, than in PP types I and IV. In all the patients endothelial dysfunction with endothelial injury was observed, witnessed by significant rising of the VEGF content in the blood serum. It have created favorable conditions for pancreatic tissue remodeling while parenchymal defect have been constituted by tissue, owing lower level of organization, including a cicatricial one. In cases of cellular repeated affection more activation of pancreatic stellate cells and enhancement of production of extracellular matrix component were noted.

[Milk-of-calcium in a pseudocyst of the pancreas]

A 59-year-old woman with a history of abdominal injury was admitted to our hospital for abdominal discomfort. CT revealed a cyst showing a fluid-calcium level in the pancreatic body. EUS-FNA was performed to aspirate the fluid in a cyst. Aspirated was milky-white odorless material. Chemical analysis showed high amylase level in the fluid. Spectroscopic analysis revealed that the fluid mainly consists of calcium phosphate. To the best of our knowledge, this is the first case of milk-of-calcium in a pancreatic pseudocyst with an analysis of cystic fluid obtained by EUS-FNA.

Biochemical analysis of pancreatic fluid collections predicts bacterial infection

BACKGROUND AND AIMS

Despite our understanding of the pathophysiology of different types of pancreatic fluid collections (PFC), few studies have attempted to correlate the biochemical analysis of PFC contents with clinical and radiological characteristics. The aim of this study was to assess the predictive value of fluid analysis for discerning collection type (pseudocyst vs acute fluid collection with necrosis), presence of infection or communication with the pancreatic duct in the setting of acute and chronic pancreatitis.

METHODS

Pancreatic fluid from 34 consecutive patients undergoing endotherapy of PFC was prospectively analyzed for seven variables: lactate dehydrogenase (LDH), total protein, albumin, glucose, amylase, lipase and specific gravity.

RESULTS

In multivariate analysis, adjusting for age and gender, high intracystic levels of protein (OR 6.2; 95% CI 1.3-37.0), LDH (OR 6.8 [2.3-38.3]), and albumin (OR 7.8 [1.3-67.4]), and low levels of glucose (OR 0.2 [0.03-0.9]) predicted the presence of PFC infection. The optimal threshold value for protein was 1000 g/dL, which achieved a sensitivity of 73% and specificity of 75% for detecting infection; the optimal cut-off for LDH was 1000 U/L (sensitivity 64%, specificity 85%), and the cut-off for albumin was 500 g/dL (sensitivity 75%, specificity 85%). There were no statistically significant differences in biochemical fluid analysis with respect to fluid collection type (pseudocysts vs acute fluid collection with necrosis) and the presence of pancreatic duct communication.

CONCLUSIONS

Biochemical analysis of PFC fluid is clinically helpful in detecting fluid infection in patients with bacteria on Gram stain or positive fluid cultures. Our findings fail to support the utility of fluid analysis in characterizing cyst type, and we caution against its use in distinguishing pseudocysts from acute fluid collection with necrosis.

Performance of endosonography-guided fine needle aspiration and biopsy in the diagnosis of pancreatic cystic lesions

OBJECTIVE

Preoperative diagnosis of cystic lesions of the pancreas remains difficult despite improvement in imaging modalities and cystic fluid analysis. The aim of our study was to assess the performance of endoscopic ultrasonography (EUS) and EUS-guided fine needle aspiration (FNA) in the diagnosis of pancreatic cystic lesions.

METHODS

Data from a series of 127 consecutive patients with pancreatic cystic lesions were prospectively studied. EUS and EUS-guided FNA were performed in all patients, and cystic material was used for cytological and histological analysis as well as for biochemical and tumor markers analysis. Performance of EUS diagnosis, biochemical and tumor markers, and FNA diagnosis were compared with the final histological diagnosis obtained at surgery or postmortem examination. Sixty-seven patients underwent surgery and therefore constituted our study group.

RESULTS

EUS provided a tentative diagnosis in 113 cases (89%). Cytohistological FNA provided a diagnosis in 98 cases (77%). When the results of EUS and EUS-guided FNA were compared with the final diagnosis (67 cases), EUS correctly identified 49 cases (73%), whereas FNA correctly identified 65 cases (97%). Sensitivity, specificity, positive predictive value, and negative predictive value of EUS and EUS-guided FNA to indicate whether a lesion needed further surgery were 71% and 97%, 30% and 100%, 49% and 100%, and 40% and 95%, respectively. Carbohydrate antigen 19-9 > 50,000 U/ml had a 15% sensitivity and a 81% specificity to distinguish mucinous cysts from other cystic lesions, whereas it had a 86% sensitivity and a 85% specificity to distinguish cystadenocarcinoma from other cystic lesions.

CONCLUSIONS

EUS-guided FNA is a valuable tool in the preoperative diagnostic assessment of pancreatic cystic lesions.

Three truncated forms of serum albumin associated with pancreatic pseudocyst

Plasma from a patient with chronic pancreatic pseudocyst showed an additional more negative albumin band (18%) on agarose gel electrophoresis. Both components bound (63)Ni(2+), indicating intact N-terminals; however, electrospray ionisation analysis of the intact proteins showed the mass of more negative albumin was 1254 Da less than the control and that the apparently normal band was 112 Da less. Reverse phase mapping and mass analysis of CNBr peptides showed three proteolytically modified forms of the C-terminal peptide indicating that some 81% of the albumin molecules lacked the C-terminal Leu residue, that 18% lacked the C-terminal KKLVAASQAALGL and that approximately 1% lacked the QAALGL sequence. These findings were further verified by tryptic mapping of the aberrant CNBr peptides. The truncations probably result from exposure of the albumin to 'leaking' pancreatic endo and exoproteases. During less acute phases of the disease, the 13 and 6 residue truncated forms together decreased to less than 1%, while the des-Leu(585) form made up the balance; no normal albumin was detected. This suggested that the des-Leu(585) form might be present at low levels in the plasma of normal individuals and CNBr mapping confirmed that it constituted 4-15% of the albumin from normal plasma.

Measurement of pS2 protein in pancreatic cyst fluids. Evidence for a potential role of pS2 protein in the pathogenesis of mucinous cystic tumors

CONCLUSION

Elevated levels of the growth factor pS2 protein in the cyst fluids of mucinous cystic tumors correlate with earlier observations using immunohistochemical techniques showing that pS2 protein is expressed by these tumors. The markedly elevated levels of pS2 protein compared to normal plasma values suggest that this growth factor may be important in the pathogenesis of pancreatic mucinous cystic tumors.

BACKGROUND

Cystic lesions of the pancreas include inflammatory pseudocysts, serous cystadenomas, and mucinous cystic tumors, some of which are malignant. Previous studies using immunohistochemical techniques have shown that virtually all pancreatic mucinous tumors express pS2 protein. pS2 protein is a growth factor that is believed to be important in the normal process of inflammation and repair. We measured pS2 protein and other growth factors in pancreatic cyst fluids to assess their potential pathophysiologic and diagnostic significance.

METHODS

Levels of pS2 protein were measured in 54 pancreatic cyst fluids by radioimmunoassay. The growth factors, epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), and insulin-like growth factors I and II (IGF-I, IGF-II) were measured in 22 cyst fluids using commercial immunoassays.

RESULTS

Mucinous cysts exhibited significantly higher levels of cyst fluid pS2 protein than nonmucinous lesions, including pseudocysts and serous cystadenomas (median: 78,303 pg/mL; range: 218-361,176 pg/mL vs median: 886 pg/mL; range: 0-14,206 pg/mL; p = 0.0001). The level of pS2 in mucinous tumors was markedly higher than plasma values (median: 392 pg/mL). Levels of pS2 protein in malignant mucinous lesions tended to be higher than those in benign mucinous cysts, but this difference was not statistically significant (median: 88,817 vs 64,350 pg/mL; p = 0.159). Levels of other growth factors, including EGF, TGF-alpha, IGF-I, and IGF-II, did not discriminate among the different cyst types, and the values were within normal plasma ranges.

Serum tumor markers and cyst fluid analysis are useful for the diagnosis of pancreatic cystic tumors

BACKGROUND

This study was performed to evaluate the utility of serum and cyst fluid analysis for enzymes (amylase and lipase) and tumor markers (carcinoembryonic antigen, CA 19-9, CA 125, and CA 72-4) in the differential diagnosis of cystic pancreatic lesions.

METHODS

Serum and cyst fluid were obtained from 48 patients with pancreatic cysts (21 pseudocysts, 14 mucinous cystic neoplasms, 6 ductal carcinomas, and 7 serous cystadenomas), observed between 1989 and 1994.

RESULTS

Serum CA 19-9 levels were significantly higher in ductal carcinomas (all > 100 U/mL) and mucinous cystic neoplasms (P < 0.05). CA 72-4 cyst fluid levels were significantly higher in mucinous cystic tumors (P < 0.005), with 95% specificity and 80% sensitivity in detecting mucinous or malignant cysts. A combined assay of serum CA 19-9 and cyst fluid CA 72-4 correctly identified 19 of 20 (pre-) malignant lesions (95%), with only 1 false-positive result (3.6%). Cytology showed a sensitivity of 48% and specificity of 100%.

CONCLUSIONS

Any pancreatic cyst with high serum CA 19-9 values, positive cytology, or high CA 72-4 in the fluid should be considered for resection.

Mucin-secreting tumors of the pancreas

Mucinous pancreatic neoplasms present diagnostic and therapeutic challenges. These tumors behave in an indolent nature, with frequent overlap of symptoms and radiographic appearance with other forms of pancreatic cysts, pseudocysts, and malignancy. Some authors propose that all mucin-producing tumors of the pancreas are variants of the same basic entity and have subclassified them on the basis of their predominant location within the pancreas. These disorders must be considered in the evaluation of chronic abdominal pain, particularly in the presence of a cystic pancreatic lesion or when associated with idiopathic chronic or acute recurrent pancreatitis. The clinicopathologic features of IMHN overlap to a great extent with classic mucinous cystic neoplasms but are different significantly enough to be distinct clinical entities. These tumors originate from the pancreatic duct epithelium, produce mucin, demonstrate a papillary growth pattern, and are considered premalignant or frankly malignant at the time of diagnosis. Both lesions biologically are much less aggressive than that of pancreatic ductal adenocarcinoma and appear to infiltrate peripancreatic tissue and to metastasize to lymph nodes or other adjacent structures late in the course of disease. Nevertheless, IMHNs are located primarily in the head of the pancreas, commonly affect elderly men, and present clinically with obstructive pancreatitis, often leading to pancreatic insufficiency, whereas mucinous cystic neoplasms are more likely to develop in the pancreatic body or tail, predominate in young women, and present with symptoms referable to tumor compression of adjacent structures. The location of the lesion is the primary differentiating feature because the lining epithelium of the two tumor types is indistinguishable pathologically. In mucinous cystic tumors, the mucus is secreted and retained within the cyst lumen because of the absence of communication between the cyst and the main pancreatic duct. In contrast, mucus produced in MDE flows into the main pancreatic duct, resulting in obstructive pancreatitis and, ultimately, dilatation of the pancreatic duct. Intraductal mucus provides an important clue to the diagnosis of intraductal pancreatic neoplasms and, whenever present, should prompt an aggressive diagnostic evaluation. Both lesions are managed by resectional surgery because the opportunity for cure is high in the absence of metastatic disease.

Proteolytic activity in pancreatic pseudocyst fluid

Pancreatic pseudocyst fluids from 15 patients were biochemically analyzed, especially concerning proteolytic activity and protease inhibitors, and correlated to the clinical course. The pseudocyst fluid was a mixture of pancreatic juice and plasma possessing a high proteolytic activity against high- as well against low-mol-wt proteins. There was practically no functional protease inhibitory capacity left, although immunoreactive inhibitors were present. No distinct biochemical findings differed between fluids from "acute" or from "chronic" pseudocysts. It is concluded, that high proteolytic activity within a pancreatic pseudocyst could well explain symptoms as well as complications caused by the pseudocyst. Biochemical analysis of the pseudocyst fluid cannot, however, be used to differentiate between pseudocysts with a harmless or a complicated course.

Percutaneous CT-guided fine needle aspiration cytology in the differential diagnosis of pancreatic lesions

Cytologic results were retrospectively evaluated in 83 patients who underwent CT-guided fine-needle aspiration of pancreatic lesions during a 5-year period. Sixty seven patients had malignant disease and 16 benign disease. The sensitivity, specificity, positive and negative predictive values, and diagnostic efficiency of fine-needle aspiration (FNA) cytology in detecting malignancy were 91%, 100%, 100%, 73%, and 93%, respectively. In solid pancreatic masses the sensitivity of FNA cytology rose to 98%, while in cystic pancreatic masses sensitivity fell to 62%. In 18 patients with cystic lesions (12 benign and 6 malignant), the cystic fluid was analyzed for amylase, CEA and CA 19-9 content. Amylase levels were high in pseudocysts and in 4/6 malignant cysts. CEA levels were low in benign cysts, and high in all malignant cysts. CA 19-9 levels were high in one pseudocyst and in all malignant cysts. Tumour marker content analysis enhanced the sensitivity of the cytologic diagnosis of malignant cysts to 92%. FNA cytology is a simple and highly accurate method in the differential diagnosis of solid pancreatic lesions. In cystic lesions, tumour marker fluid content determination increases the sensitivity of FNA cytology.

Expression of CA 72-4 (TAG-72) in the fluid contents of pancreatic cysts. A new marker to distinguish malignant pancreatic cystic tumors from benign neoplasms and pseudocysts

OBJECTIVE

The authors evaluated cyst fluid CA 72-4 as a tumor marker in the differential diagnosis of pancreatic cystic lesions.

SUMMARY BACKGROUND DATA

Pancreatic cystic lesions include inflammatory pseudocysts, serious cystadenomas, and mucinous tumors. Mucinous tumors can be further subdivided into mucinous cystadenocarcinomas and premalignant mucinous cystic neoplasms. The clinical and radiologic features of these lesions are unreliable to make a preoperative diagnosis of these diagnostically difficult lesions. Analysis of aspirated cyst fluid was proposed as an aid to making the preoperative differential diagnosis. Currently, a number of parameters have been reported as useful markers in cyst fluid aspirates, including the tumor markers carcinoembryonic antigen and CA 15.3, enzymes (amylase, lipase, and amylase isoenzymes), relative viscosity, and cytologic analysis. However, owing to the rarity of pancreatic cystic tumors, experience with cyst fluid analysis is limited. To define additional markers that might be useful in the differential diagnosis of pancreatic cysts, the authors measured the tumor-associated glycoprotein 72 (TAG-72) in aspirates from 19 pancreatic cystic lesions.

METHODS

Cyst fluid from 19 pancreatic cysts was obtained by needle aspiration. The tumor marker TAG-72 was measured by a commercial (CA 72-4) immunoassay.

RESULTS

Cyst fluid CA 72-4 levels in mucinous cystadenocarcinomas were markedly elevated (mean, 10,027 U/mL; range, 780 to 34,853 U/mL) compared with that in pseudocysts (mean, 3.8 U/mL; range, < 3 to 5.7 U/mL) and serous cystadenomas (mean and range, < 3 U/mL; p < 0.001). The level of CA 72-4 in benign mucinous cystic neoplasms was intermediate (mean, 44.2 U/mL; range, < 3 to 137 U/mL), but it was statistically different from either carcinomas (p = 0.009) or benign cysts (p < 0.001).

Mucin-producing pancreatic tumor: CT findings and histopathologic correlation

Twenty patients with mucin-producing pancreatic tumor and 60 with other pancreatic diseases underwent computed tomography (CT) to establish the CT characteristics of mucin-producing pancreatic tumor. Scans were obtained with thin sections by administering a large volume of contrast material (200 mL). Mucin-producing pancreatic tumors were divided into three subgroups, and the CT characteristics were as follows: Main duct type tumors consisted of a cystic mass in or communicating with the dilated main pancreatic duct (MPD). Excrescent nodules and/or septa were found in the cyst. The MPD was markedly dilated over its entire length. Branch duct type tumors consisted of clustered small cysts that were all approximately the same size in diameter (1-2 cm). Excrescent nodules or septa were not always seen. The MPD near the lesion was often slightly dilated. Peripheral type tumors consisted of a well-defined cystic mass with excrescent nodules and/or septa. Even if the cyst was multilocular, a large main cyst was in it. The MPD usually was not dilated. The CT findings corresponded to macroscopic findings. Mucin-producing pancreatic tumor can be differentiated from other pancreatic diseases with these criteria.

Pancreatic pseudocyst fluid--a mixture of plasma proteins and pancreatic juice possessing a high proteolytic activity

Pancreatic pseudocyst fluid from eight patients was examined biochemically. The fluid was found to be a mixture of plasma proteins and pancreatic juice, possessing a high proteolytic activity against high- as well as low-molecular-weight proteins. The proteolytic activity was found to be trypsin-, kallikrein- and plasmin-like. Gel filtration studies showed proteolytic activity to be present corresponding to alpha-2-macroglobulin-bound proteases and also to free proteases. Quantitative immunochemical levels were about 30-100% of normal plasma levels for alpha-2-macroglobulin, C1 inhibitor, antithrombin III and alpha-2-antiplasmin. However, there was practically no functional inhibitory capacity left in the pseudocyst fluid, except for alpha-1-protease inhibitor, which retained its inhibitory capacity. Neither native kininogen nor complement factor C3 was found: this was probably a result of the proteolytic activity. It is concluded, that a continuing proteolytic activity within the pseudocyst, although decreasing with aging of the cyst, could explain symptoms and complications caused by the pseudocyst.

Penetration of cefotaxime into the pancreas

After intravenous injection of cefotaxime, higher pancreatic concentrations of the antibiotic were found in rats with experimental pancreatitis than in control animals. Also in human pancreatic pseudocysts, high and persistent concentrations of cefotaxime were found following intravenous injection. The results justify the use of cefotaxime in acute pancreatitis, whenever an antibiotic is indicated.

Biochemical and cytological analyses of cystic fluid aspirated by percutaneous puncture under ultrasonic guidance in cystic diseases of the pancreas

Ultrasonically guided percutaneous puncture of pancreatic cyst was performed on 4 patients with ultrasonically scanned cystic mass lesions in the left upper quadrant, and biochemical and cytological analyses of the aspirated cystic fluids were proved fairly diagnostic. In pseudocyst, the aspirated fluid revealed very high concentration of amylase, malignant cells being not recognized cytologically. In cystadenocarcinoma, the aspirated fluid revealed low concentrations of amylase and high concentrations of LDH and CEA, malignant cells being definitely recognized. This method is of great value for differential diagnosis of cystic diseases of the pancreas.