CYSTIC TUMORS OF THE PANCREAS basics.pptx

mucinous cystic,serous cystic, IPMN

1. CYSTIC TUMORS OF THE PANCREAS

2. relatively uncommon, accounting for less than 10% of pancreatic neoplasms . MRI series have found a prevalence up to 20%, with a cumulative prevalence of 40% in patients older than 70.178 A recent review of 24,000 abdominal CT and MRI studies at 1 institution during an 8-year period revealed that pancreatic cysts were present in 1.2% of patients, and 60% of these were likely to be cystic neoplasms.179 MCN, SCNs, IPMNs comprise more than 80% of the primary cystic neoplasms of the pancreas Accurate recognition of these lesions is important because of their ability to mimic as pancreatic pseudocysts , and their high cure rate following surgical treatment.

3. pseudocysts often have a history of acute or chronic pancreatitis, or abdominal trauma Characteristics that favor a diagnosis of pseudocyst over cystic neoplasms include lack of septae , loculations , solid components or cyst wall calcifications on CT or MRI MRCP traditionally demonstrates communication pseudocyst fluid reveals high levels of amylase The initial challenge is to segregate benign from potentially malignant cystic tumors (see later). The more difficult task is to separate premalignant from invasive tumors

4. diagnostic examination of choice is an MRI of the abdomen with MRCP then a CT with pancreatic protocol is a good alternative ERCP is useful for the diagnosis of IPMN and allows procurement of biopsy samples by brushings EUS allows detailed characterization of the cyst wall, identifying fine structures such as septa, papilla, or wall nodules (Fig. 60.9). Additionally, FNA of the cyst contents is possible with EUS. Cyst fluid analysis is helpful in the evaluation of cystic neoplasms (Table 60.7).176

5. Classification Pancreatic cysts can be categorized into the following groups: Pseudocysts Common cystic neoplasms : IPMN - intraductal papillary mucinous neoplasm SCN - Serous cystic neoplasm MCN - Mucinous cystic neoplasm Uncommon cystic neoplasms : SPEN (solid pseudopapillary epithelial neoplasm) Tumors with cystic degeneration: adenocarcinoma - neuroendocrine tumor

6. Mucinous Cystic Neoplasms prevalence of MCNs to be approximately half that of IPMNs.181,182 F:M=20:1 , age of presentation 50 yr, confined to the body and tail (95% of cases) solitary, multiloculated or unilocular lesions with a thick fibrotic wall Most patients complained primarily of abdominal pain or a palpable mass/ incidentaly detected CT or MRI of the abdomen shows a cyst within the body or tail of the pancreas in a middle-aged woman MRCP- no communication between cyst and duct(IPMN has a communication) EUS can identify septations and cyst wall nodules , and allows cyst wall biopsy and cyst fluid aspiration for analysis Cyst fluid analysis generally reveals thick and mucoid material, low fluid amylase, elevated tumor markers (CEA), and mucinous epithelial cells by cytology.

7. Treatment inherent potential for malignancy in MCNs, surgical resection is advocated for all of them. Distal pancreatectomy with or without splenectomy is the procedure of choice small or benign-appearing lesions, enucleation can be performed without risk of local recurrence for benign or borderline MCNs, cure rate is 100%.185,188 For invasive MCNs, 5-year survival rates range from 30% to 63% in resected tumors.183,188

8. Serous Cystadenomas predominantly benign tumors with little risk of malignant behavior. clinical presentation is similar to that of MCNs, occurring mostly in the body or tail of the pancreas in women (75%) with a mean age of 62 years.190 A/w Von Hippel-Lindau disease Macroscopically serous cystadenomas consist of well-circumscribed with numerous tiny cysts separated by delicate fibrous septa, giving them a honeycomb appearance (Fig. 60.11).192 The cysts are filled with clear watery fluid and are arranged around a central stellate scar that may be calcified CT image - a spongy mass with a central “sunburst” calcification(seen only in 10%) Macrocystic variants occur and tumors may undergo cystic degeneration, leading to confusion with pseudocysts or MCNs

9. Cystic fluid analysis

10. considered benign tumors. Rare case reports of serous cystadenocarcinomas exist but constitute less than 3% of known cases.194 Surgical resection is the treatment of choice for symptomatic lesions. Options for resection depend on tumor location and include distal pancreatectomy with or without splenectomy , Whipple procedure, middle pancreatectomy , or enucleation . safely observed if asymptomatic risk of continued growth, which may lead to complications such as hemorrhage, mass effect causing obstructive jaundice and pancreatic duct obstruction with exocrine insufficiency,or gastric outlet obstruction.195 Two different growth patterns have been documented, slow (1 mm/year) and more rapid (5 mm/year).196 rapid enlargement of the mass should raise the index of suspicion for serous cystadenocarcinoma and consideration for surgical resection.

11. Intraductal Papillary Mucinous Neoplasms diagnosed incidentally with true prevalence unknown, ranging from 0.0008% to 10% in patients older than 70 years. Other terms used are mucinous ductal ectasia, intraductal mucin-producing tumor, intraductal cystadenoma , pancreatic duct villous adenoma, and intraductal papillary neoplasm. equal frequency in men and women, with a median age at diagnosis of approximately 65 years. Approximately 75% of patients are symptomatic, with abdominal pain and weight loss being the MC complaints. A h/o recurrent pancreatitis 20% of patients, and acute pancreatitis is found in 25% at presentation. IPMNs of the main duct  mucin hypersecretion  duct dilation  chronic obstructive pancreatitis

12. IPMNs are considered premalignant pancreatic lesions on their histologic characteristics, IPMNs are generally classified into the following groups: benign (adenoma)/ borderline/or malignant.203 The malignant group is further subclassified into noninvasive (carcinoma in situ) and invasive carcinoma based on extension beyond the basement membrane malignant neoplasm was 64% in main duct IPMN and 18% in patients with branch duct IPMN.204 patients with malignant neoplasms are more likely to be older and more likely to present with jaundice or new-onset diabetes.205

13. CT scan-Duct dilation may mimic MCNs on (Fig. 60.14). MRI finds mural nodules (60% vs. 4%) and wall enhancement (74% vs. 21%) more frequently in malignant versus benign or borderline IPMN.206 ERCP typically shows a patulous ampulla of Vater with extruding mucus, a finding that is pathognomonic for main duct IPMNs. Other findings during pancreatography include main duct dilation, filling defects caused by viscid mucus or tumor nodules (Fig. 60.15), and communication between cystic areas and the main pancreatic duct.

14. Treatment of IPMN TOC-pancreatic resection,which successfully relieves symptoms and prevents tumor progression to invasive carcinoma. Pancreaticoduodenectomy is the TOC for IPMNs in the head of the pancreas, distal pancreatectomy for lesions in the body or tail of the gland. Intraoperative frozen sections are necessary to rule out malignancy at the resection margin, low-grade dysplasia at the margin should not lead to total pancreatectomy . Residual ductal dysplasia did not predict the development of invasive disease or reduced survival.207 dysplasia at the margin was associated with recurrence in the remnant gland, but this was not at the resected margin.208

15. Prognosis Prognosis after resection of IPMN is excellent, with 5-year disease-specific survival of at least 75%, predicted by the presence or absence of invasion at primary resection. Factors associated with worse outcome in patients with invasive histology include LN metastases, lymphovascular invasion, perineural invasion, and positive margins.209 Disease recurrence in the pancreatic remnant is often seen after resection even in noninvasive IPMNs 21% of patients had recurrence at a median follow-up of 46 months.208 follow-up of 73 months, 20% of 153 margin-negative patients had recurrence lesions.207 chances of recurrence of an invasive tumor were 0%, 7%, and 38% at 1, 5, and 10 years, respectively.210 indefinite close surveillance and postoperative imaging for those even without invasive tumors

16. Solid Pseudopapillary Tumors account for less than 10% of the cystic tumors of the pancreas.176 F:M=10:1, Peak age 30s, 20 % cases between 1-18yr ,5% cases >50 yr(212,211) C/F- MC abdominal pain( 67% to 81%)213,214 > large abdominal mass(35%)>15% incidentally detected. Most (60%) body and tail of the pancreas. 34% of patients having masses larger than 10 cm in diameter. Grossly, small tumors are relatively solid, whereas larger variants show significant cystic degeneration. Microscopically, a mixture of solid, pseudopapillary , and hemorrhagic pseudocystic areas are observed. Uniform neoplastic tumor cells are seen separated by vascular hyalinized stroma.217

17. considered to be lesions of uncertain malignant potential. A large meta-analysis of published series found a 20% frequency of solid pseudopapillary carcinoma.211 Current criteria for malignancy include perineural invasion, angioinvasion , invasion of adjacent tissues, or metastases.211 The most common site of metastasis is the liver, and metastatic disease is observed in 5% to 10% of patients at presentation complete loss of E- cadherin expression d/t abnormal expression of partner molecules such as β- catenin and p120.219 Molecular studies found that 90% of cases had a point mutation of exon 3 in the β- catenin gene.220 This finding is of diagnostic use, and loss of cell-to-cell adhesion may help to explain the cystic degeneration observed in this neoplasm.

18. very slow-growing neoplasms , with overall survival better than 90%. Complete resection is the treatment of choice.214,221