胰腺囊性病變的影像診斷課件

1、CYSTIC LEISIONS OF PANCREASIntroductionClassificationSystematic ApproachMRI versus CTSmall pancreatic cystsHow to reportManagementPseudocystCystic NeoplasmsAge and genderSerous cystic neoplasmMucinous Cystic NeoplasmaIntraductal Papillary Mucinous NeoplasmMain-duct IPMNBranch-duct IPMNUncommon Neopl

2、asms with specific findingsSolid Pseudopapillary NeoplasmNeuroendocrine tumor with cystic degenerationClassificationPancreatic cysts can be categorized into the following groups:PseudocystsCommon cystic neoplasms:IPMN - intraductal papillary mucinous neoplasmSCN - Serous cystic neoplasmMCN - Mucinou

3、s cystic neoplasmUncommon cystic neoplasms:SPEN (solid pseudopapillary epithelial neoplasm)Tumors with cystic degeneration: adenocarcinoma - neuroendocrine tumorSystematic ApproachThe left CT-image is of a patient with a history of pancreatitis. There are two unilocular or simple cysts. Notice also

4、the retroperitoneal fat-stranding on the right.The most likely diagnosis is pseudocysts. The CT on the right shows a cyst in the pancreatic tail in a 36 year old woman, which was found incidentally with US. The cyst has a thick irregular rim and contains solid non-dependent components. The most like

5、ly diagnosis is a cystic neoplasm.MRI is usually of more diagnostic than CTMRI can show the cystic nature of a pancreatic lesion and its internal structure. The MRI shows a large cyst with dependent internal debris (figure). Presence of internal dependent debris appears to be a highly specific MR fi

6、nding for the diagnosis of pancreatic pseudocyst (6).MRI versus CTCT will depict most pancreatic lesions, but is sometimes unable to depict the cystic component. MR with heavily weighted T2WI and MRCP will better demonstrate the cystic nature and the internal structure of the cyst and has the advant

7、age of demonstrating the relationship of the cyst to the pancreatic duct as is seen in IPMN. The images show a serous cystic neoplasm (SCN). MRI better shows the central scar (figure). There are cases when CT can be helpful, since it better depicts a central calcification in SCN or peripheral calcif

8、ication in a mucinous cystic neoplasm (MCN).SCN with central scar seen on MRIMRI shows dependent debris in pseudocystMRI shows a lesion, which consists of multiple small cysts.This could be a serous cystic neoplasm or a branch-duct IPMN.The connection of the cystic lesion to the pancreatic duct indi

9、cates that this is a branch-duct IPMN.Small pancreatic cystsHow to reportSmall pancreatic cysts have been documented in approximately 2.3% of CT studies and up to 19% of MR studies (11). Most of these cysts are found in asymptomatic patients, who are studied for other reasons and represent benign or

10、 low-grade indolent neoplasms. The ability of imaging to enable a specific diagnosis of an individual pancreatic cyst is limited, but is easier in larger cystic lesions. In most small cysts we should not attempt to characterize the lesion and when we do, we should not be too confident. The managemen

11、t of cystic neoplasms has not yet been standardized and continues to evolve.According to the recent 2012 consensus guidelines by Tanaka et al the items mentioned in the Table should be addressed (8).ManagementAge, life-expectancy and comorbidity should be considered in the possible surveillance or t

12、reatment. Cysts smaller than 3 cm and no worrisome or high risk-features can be considered for follow-up with either MRI, CT or ultrasound. Cysts with obvious high risk stigmata should be considered for resection.The table shows the American College of Radiology flowchart for imaging of incidentally

13、 discovered pancreatic cysts in asymptomatic patients (11).Pancreatic cysts are regarded symptomatic when there is hyperamylasemia, recent-onset diabetes, severe epigastric pain, weight loss, steatorrhea, or jaundice. Pseudocystkey findings:Unilocular cyst without solid components, central scar or w

14、all calcification.Collection of pancreatic enzymes, blood and necrotic tissue.Debris within a cystic lesion is a specific MR finding (6).History of pancreatitis or abdominal trauma.Cysts develop in 4-6 weeks - usually decrease in size over time - sometimes enlarge or become infected.Found in any par

15、t of the pancreas or anywhere within the abdomen and sometimes even in the chest.The CT demonstrates a large cyst in the upper abdomen in a patient who had an acute pancreatitis. Notice that there is also some ascites and pleural fluid. There wall enhances.Here an example of the value of MRI compare

16、d to CT. The MRI shows dependant debris (arrow) as a discriminator for walled off necrosis in a patient with a pseudocyst.CT demonstrates two large cysts in a 45 year old woman, who had a trauma.Notice some fat stranding in the retroperitoneal space (arrow). The imaging findings combined with the hi

17、story make it very likely that these are traumatic pseudocysts.Most pseudocyst occur in the peripancreatic region, but rarely they may extend to the mediastinum.This patient has a chronic pancreatitis.Notice the calcifications in the pancreatic head (curved arrow).There are multiple pseudocysts exte

18、nding all the way to the mediastinum compressing the heart.Cystic NeoplasmsCystic NeoplasmsThe diagnosis of a cystic neoplasm should be considered when there is no history of pancreatitis or trauma.Morphological characteristics of a cystic neoplasm are: thick irregular rim, septations, solid compone

19、nts, a dilated pancreatic duct 3mm and calcifications.In many cases however it is not possible to make a definitive diagnosis.It is important to make the diagnosis of a serous cystic neoplasm, since this is the only tumor that has no malignant potential.In many cases differentiation from a branch-du

20、ct IPMN is difficult, since both have multiple small cysts.Age and genderSome cystic neoplasm are seen almost exclusively in women, like mucinous cystic neoplasm (99%) and serous cystic neoplasm (75%).Solid pseudopapillary epithelial neoplasm is another pancreatic tumor which may have cystic compone

21、nts. It is uncommon, but is seen exclusively in young women. Hence the following rule:Grandma - Serous cystic adenomaMother - Mucinous cystic neoplasmDaughter - Solid pseudopapillary epithelial neoplasm SPENSerous cystic neoplasmkey findings:Benign tumor, but large tumors have a tendency to increase

22、 in size and cause symptomsTypically seen in GrandmaMicrocystic or honey-combed cyst with central scar (30%) and calcifications (18%)Macrocystic in 10% and difficult to differentiate from pseudocyst and mucinous cystic neoplasmLobulated surfaceNo communication between cysts and pancreatic duct.Hyper

23、vascular enhancement is sometimes seen and can look like cystic neuroendocrine tumorGrowth rate of tumors：Growth rate of tumors 4 cm: up to 20 mm/ySerous cystic adenomas contain multiple small cysts resulting in a lobulated contour. Some have a central scar with calcifications.The pathology specimen

24、 shows multiple microcysts, which gives the tumor a lobulated appearance.A macrocystic serous cystic neoplasm is rare and, although benign, can be similar in appearance to the potentially malignant macrocystic mucinous cystic neoplasm.Courtesy of Dr Allen, HPB surgery, Memorial Sloan Kettering Cance

25、r Center, NYA characteristic feature of a serous cystic neoplasm is a central scar, sometimes with calcifications.Sometimes the microcystic component of this tumor is difficult to identify on CT.MR will better identify the internal architecture.MRI is also useful in determining if the cysts communic

26、ate with the pancreatic duct or not to differentiate this lesion from a branch-duct IPMN (see below).The pathology specimen shows a cystic tumor with multiple small cysts and a central scar.There are no calcifications.Courtesy of Dr Klimstra, pathology of the Memorial Sloan Kettering Cancer Center,

27、NY,CT-image of a 51 year old woman with a history of gallstones and abdominal pain. There is a hypodense lesion with central calcification in the head of the pancreas. The lesion has a lobulated contour. Continue with the MR.Serous Cystic Neoplasm (SCN)MRI better demonstrates the morphologic feature

28、s of the lesion. On T2WI the lesion is multicystic. Note the central low signal due to the central scar with calcifications.Although some of the cysts are rather large, this is still a characteristic appearance of a serous cystic adenoma.Serous Cystic Neoplasm (SCN)Another example of a serous cystic

29、 neoplasm. The enhanced image on the right shows a hypodense lesion with central calcification in the body of the pancreas. On the right image subtle enhancement of septations are seen.Notice that on CT it is very difficult to appreciate the cystic nature of these lesions and you might think that yo

30、u are dealing with a pancreatic adenocarcinoma.Serous Cystic Neoplasm (SCN)MRI will easily demonstrate the cystic nature of these lesions.The T2WI with fatsat nicely demonstrates a lobuated hyperintense lesion with central scar, which is characteristic of a SCN.Serous Cystic Neoplasm (SCN)It may be

31、difficult to differentiate a serous microcystic adenoma from a branch-duct IPMN or intraductal papillary mucinous neoplasm.IPMN is always connected to the pancreatic duct.T2WI of a 71 year old man with a history of weight loss and nondescript upper abdominal complaints.This was initially thought to

32、be a branch-duct IPMN, but turned out to be a SCN.Notice the central hypointensity.This is scar tissue in a SCN.Notice also the characteristic lobulated surface.Another example of a serous cystadenoma. Notice the central enhancement. Sometimes differentiation from a hypervascular cystic neuroendocri

33、ne tumor can be difficult, but in this case the central calcifications are helpful.Courtesy Koenraad Mortel, Dept Radiology, Brigham and Womens hospital, BostonIn the pancreatic tail is a cystic lesion with a central scar with calcifications (arrow). Eventhough some of the cyst are larger than 2 cm,

34、 this presentation still is typical for a serous cystic neoplasm, because of the central scar, multilocular appearance and the lobulated contour.This patient had abdominal complaints which were attributed to the tumor, which was resected and proved to be a serous cystic neoplasm.Serous cystic neopla

35、sm.This is the resected specimen. The tumor was attached to the spleen, which also had to be resected.Another case of a typical serous cystic neoplasm. There is a microcystic lesion with a central scar in the pancreatic head. This patient felt a mass in her abdomen.Otherwise there were no complaints

36、. Because resection would mean extensive surgery, it was decided to follow the lesion. During 5 year follow up there was no growth and the patient has no symptoms otherwise.Serous cystic neoplasmMucinous Cystic Neoplasmakey findings:Premalignant tumor - may transform into a mucinous cystadenocarcino

37、maExclusively seen in women - Typically in Mother - median age: 40-50 yearsMacrocystic with thick wall septations and peripheral calcificationsPeripheral calcifications seen in 25%. This finding allows you to make a specific diagnosisLocation in the tail and body of the pancreas (95%).Most are sympt

38、omatic, presenting with nondescript abdominal painCT-images of a 32 year-old female with pain in the upper left quadrant radiating to the back. There is a large cyst in the pancreatic tail with peripheral calcification. There is subtle septation as seen on the left image and wall thickening. You may

39、 have to enlarge the image to see the septation. A specific diagnosis of a MCN can be made.Intraductal Papillary Mucinous Neoplasmkey findings:Mucine producing tumor in main pancreatic duct or branch-duct.Location: pancreatic head tail and corpus.Must have communication with pancreatic duct. Best se

40、en with MRCP.Can be multifocal.Main-duct IPMN has imaging features distinct from branch-type.Branch-duct type can look like other cystic neoplasmsMacroscopic specimen of a IPMN showing mucinous tumor, with extensive mucin producing papilary neoplasm (arrow).Main-duct IPMNOn imaging Main-duct IPMN is

41、 distinct from branch-duct IPMN, but sometimes there is a mixed type.the images of a large main duct and branch-duct IPMN. There is obstruction of the common bile duct with dilatation of the intrahepatic bile ducts (blue arrows). Notice the extremely widened main pancreatic duct (red arrow).Normal T

42、2WI and heavily T2WI with fatsat of a large main duct IPMN with extremely dilated pancreatic duct.This patient presented with pancreatitis. The MRCP shows both a main-duct aswell as a branch-duct IPMN (arrow).IPMN is a lesion with malignant potential.Signs of malignancy are:Pancreatic duct 8 mm - as

43、 in this case.Solid node in duct.Mass around the pancreatic duct.Enlarged choledochal duct.CT-images of an IPMN with a dilated pancreatic duct (blue arrows).Notice enhancing solid nodule in the pancreatic head (red arrow). Continue with US-image.IPMN with malignant transformationThe US-image shows a

44、 large branch-duct component within the pancreatic head.Main duct and branch-duct IPMNThe CT-image shows a hypodense lesion in the pancreatic head. This could be an adenocarcinoma, but the low density makes you think of a cystic tumor. The microcystic appearance raises the possibility of a serous cy

45、stic neoplasm although there is no calcified scar. On MRCP the cystic nature is better appreciated and there is a connection to a widened duct (blue arrow).Branch-duct IPMNA detail nicely demonstrates that some of the mucus-filled branches are seen in cross-section and some longitudinally.In a 73 year old male a hypoechoic lesion was found in the pancreatic body, that looked like a cystic lesion. CT also identifies the lesion but isnt of much h