F-18-fluorodeoxyglucose positron emission tomography in differentiating malignant from benign pancreatic cysts: A prospective study

The differential diagnosis between benign and malignant pancreatic cystic lesions may be very difficult. We recently found that F-18-.uorodeoxyglucose positron emission tomography (18-FDG PET) was useful for the preoperative work-up of pancreatic cystic lesions. This study was undertaken to confirm these results. From February 2000 to July 2003, 50 patients with a pancreatic cystic lesion were prospectively investigated with 18-FDG PET in addition to helical computed tomography (CT) and, in some instances, magnetic resonance imaging (MRI). The validation of diagnosis was based on pathologic findings after surgery (n = 31), percutaneous biopsy (n = 4), and according to follow-up in 15 patients. The 18-FDG PET was analyzed visually and semiquantitatively using the standard uptake value (SUV). The accuracy of FDG PET and CT was determined for preoperative diagnosis of malignant cystic lesions. Seventeen patients had malignant cystic lesions. Sixteen (94%) showed increased 18-FDG uptake (SUV >2.5), including two patients with carcinoma in situ. Eleven patients (65%) were correctly identified as having malignancy by CT. Thirty-three patients had benign tumors: two patients showed increased 18-FDG uptake, and four patients showed CT findings of malignancy. Sensitivity, specificity, positive and negative predictive value, and accuracy of 18-FDG PET and CT in detecting malignant tumors were 94%, 94%, 89%, 97%, and 94% and 65%, 88%, 73%, 83%, and 80%, respectively. 18-FDG PET is accurate in identifying malignant pancreatic cystic lesions and should be used in combination with CT in the preoperative evaluation of patients with pancreatic cystic lesions. A negative result with 18-FDG PET may avoid unnecessary operation in asymptomatic or high-risk patients. Presented at the Forty-Fifth Annual Meeting of The Society for Surgery of the Alimentary Tract, New Orleans, Louisiana, May 15–19, 2004 (oral presentation). This study was supported by the Ministero Università e Ricerca Scientifica (Cofin 2001068593-001), Rome, Italy.     

18-fluorodeoxyglucose positron emission tomography enhances computed tomography diagnosis of malignant intraductal papillary mucinous neoplasms of the pancreas

OBJECTIVE: To assess the reliability of 18-fluorodeoxyglucose positron emission tomography (18-FDG PET) in distinguishing benign from malignant intraductal papillary mucinous neoplasms (IPMNs) of the pancreas and its contribution to surgical decision making. SUMMARY BACKGROUND DATA: Pancreatic IPMNs are increasingly recognized, often as incidental findings, especially in people over age 70 and 80. Computed tomography (CT) and magnetic resonance (MR) are unreliable in discriminating a benign from a malignant neoplasm. 18-FDG PET as imaging procedure based on the increased glucose uptake by tumor cells has been suggested for diagnosis and staging of pancreatic cancer. METHODS: From January 1998 to December 2005, 64 patients with suspected IPMNs were prospectively investigated with 18-FDG PET in addition to conventional imaging techniques [helical-CT in all and MR and magnetic resonance cholangiopancreatography (MRCP) in 60]. 18-FDG PET was analyzed visually and semiquantitatively using the standard uptake value (SUV). The validation of the diagnosis was made by a surgical procedure (n = 44), a percutaneous biopsy (n = 2), main duct cytology (n = 1), or follow-up (n = 17). Mean and median follow-up times were 25 and 27.5 months, respectively (range, 12-90 months). RESULTS: Twenty-seven patients (42%) were asymptomatic. Forty-two patients underwent pancreatic resection, 2 palliative surgery, and 20 did not undergo surgery. An adenoma was diagnosed in 13 patients, a borderline tumor in 8, a carcinoma in situ in 5, and an invasive cancer in 21; in 17 patients a tumor sampling was not performed and therefore the histology remained undetermined. Positive criteria of increased uptake on 18-FDG PET was absent in 13 of 13 adenomas and 7 of 8 borderline IPMNs, but was present in 4 of 5 carcinoma in situ (80%) and in 20 of 21 invasive cancers (95%). Conventional imaging technique was strongly suggestive of malignancy in 2 of 5 carcinomas in situ and in 13 of 21 invasive carcinomas (62%). Furthermore, conventional imaging had findings that would be considered falsely positive in 1 of 13 adenomas (8%) and in 3 of 8 borderline neoplasms (37.5%). Therefore, positive 18-FDG PET influenced surgical decision making in 10 patients with malignant IPMN. Furthermore, negative findings on 18-FDG PET prompted us to use a more limited resection in 15 patients, and offered a follow-up strategy in 18 patients (3 positive at CT scan) for the future development of a malignancy. CONCLUSIONS: 18-FDG PET is more accurate than conventional imaging techniques (CT and MR) in distinguishing benign from malignant (invasive and noninvasive) IPMNs. 18-FDG PET seems to be much better than conventional imaging techniques in selecting IPMNs patients, especially when old and asymptomatic, for surgical treatment or follow-up.     

Clinical usefulness of 18-fluorodeoxyglucose positron emission tomography in the management of patients with nonpancreatic periampullary neoplasms

BACKGROUND: 18-Fluorodeoxyglucose positron emission tomography (18-FDG PET) has been investigated for the diagnosis and staging of gastrointestinal malignancies including pancreatic adenocarcinoma. The aim of this study was to examine the clinical usefulness of 18-FDG PET in the diagnosis and follow-up evaluation of patients with periampullary neoplasms. METHODS: Twenty-five patients underwent whole-body 18-FDG PET and abdominal computed tomography (CT). Pathologic confirmation was obtained in all patients by surgical resection or biopsy examination. The 18-FDG PET was analyzed visually and semiquantitatively using the standard uptake value (SUV). Positivity was assumed when a focal uptake occurred with an SUV of 2.5 or greater. RESULTS: Between January 1998 and December 2003, 14 ampullary, 7 bile duct, and 4 duodenal tumors were included in the study. PET showed increased focal uptake in 22 patients (88%): 11 of 14 (79%) ampullary tumors, and 100% of bile duct and duodenal tumors. PET showed a focal uptake in 11 of 12 patients without detectable mass at CT scan, and lymph node metastases in 6 patients. An SUV value of 2.7 discriminated adenomas or noninvasive cancers (n = 6) from invasive malignancies (n = 14). Follow-up evaluation including CT scan and PET was performed in 12 patients: PET showed recurrent disease not seen by CT in 4 patients, confirmed CT findings in 6 patients, and showed an unsuspected primary lung cancer in 1 patient and colon cancer in another patient. CONCLUSIONS: 18-FDG PET is very sensitive for detecting periampullary neoplasms. It may be useful to differentiate benign or borderline lesions from invasive tumors when no mass has been identified by traditional imaging. Finally, it is very useful in the follow-up evaluation of resected patients to identify recurrent disease or other malignancies.     

K-ras oncogene mutations indicate malignancy in cystic tumors of the pancreas.

OBJECTIVE: To evaluate clinical parameters, presurgical diagnostic tests, histologic findings, and the presence of K-ras oncogene mutations in cystic tumors of the pancreas to determine which best predict malignancy. SUMMARY BACKGROUND DATA: Because presurgical, intraoperative, and final pathologic differentiation is difficult in cystic tumors of the pancreas, it would be a major benefit to identify markers that accurately predict malignancy in these rare tumors. The role of K-ras oncogene mutations as an indicator of malignancy has not been determined in these tumors. METHODS: Nineteen patients with cystic tumors of the pancreas were evaluated, including K-ras mutation analysis based on polymerase chain reaction and restriction digestion assays and direct DNA sequencing, to screen for parameters that accurately predict malignancy. RESULTS: All malignant cystic pancreatic tumors (five cystadenocarcinomas and three mucin-producing adenocarcinomas) harbored K-ras mutations at codon 12 or 13. K-ras mutations were also detected in the percutaneous fine-needle aspirates of two of these patients. In contrast, none of nine benign cystadenomas or the solid-papillary neoplasm had K-ras mutations. None of the patients with a benign tumor carrying K-ras wild-type sequences developed recurrent disease after a mean follow-up of 50 months. Seven of the 8 malignant cystic pancreatic tumors, but none of the 11 benign tumors, showed dilatation of the main pancreatic duct on computed tomography or endoscopic retrograde cholangiopancreatography. CONCLUSIONS: K-ras mutation analysis seems to be a powerful tool to determine the malignant potential of cystic pancreatic tumors before and after surgery. Dilatation of the main pancreatic duct on computed tomography or endoscopic retrograde cholangiopancreatography is highly suggestive for malignancy in these rare tumors.     

The utility of F-18 fluorodeoxyglucose whole body PET imaging for determining malignancy in cystic lesions of the pancreas

Previous studies have suggested that whole body positron-emission tomography (PET) can distinguish between benign and malignant cysts of the pancreas. Patients were identified (n=68) who had undergone whole body PET imaging for a cystic lesion of the pancreas between Jan. 1997 and May 2005. Cross-sectional imaging studies were reviewed by a single blinded radiologist, and positive PET studies were reviewed by a blinded nuclear medicine physician. Operative resection was performed in 21 patients (31%), and 47 patients were managed with radiographic follow-up. F-18 Fluorodeoxyglucose (FDG)-avid lesions were identified in eight of the 68 patients (12%). Within the resected group of patients (n=21), four of the seven patients (57%) with either in situ or invasive malignancy (adenocarcinoma: 3 of 5, papillary mucinous carcinoma: 1 of 2) had positive PET imaging (mean SUV, 5.9; range 2.5-8.0), and 2 of the 14 patients (14%) with benign lesions had positive PET imaging (serous cystadenoma, n=1, SUV=3.3; pseudocyst n=1, SUV=2.7). All lesions proven to be malignant with increased FDG uptake had highly suspicious findings on cross-sectional imaging. Within the group of resected patients, the sensitivity of PET for identifying malignant pathology was 57%, and the specificity was 85%. The sensitivity and specificity of PET for malignancy in this study was lower than previously reported, and PET findings did not identify otherwise occult malignant cysts. We do not believe whole body FDG-PET to be essential in the evaluation of cystic lesions of the pancreas.     

Cystadenomas and cystadenocarcinomas of the pancreas: a multiinstitutional retrospective study of 398 cases. French Surgical Association.

OBJECTIVE: To review the features of patients with benign and malignant cystadenomas of the pancreas, focusing on preoperative diagnostic accuracy and long-term outcome, especially for nonoperated serous cystadenomas and resected cystadenocarcinomas. SUMMARY BACKGROUND DATA: Serous cystadenomas (SCAs) are benign tumors. Mucinous cystic neoplasms should be resected because of the risk of malignant progression. A correct preoperative diagnosis of tumor type is based on morphologic criteria. Despite the high quality of recent imaging procedures, the diagnosis frequently remains uncertain. Invasive investigations such as endosonography and diagnostic aspiration of cystic fluid may be helpful, but their assessment is limited to small series. The management of typical SCA may require resection or observation. Survival after pancreatic resection seems better for cystadenocarcinomas (MCACs) than for ductal adenocarcinomas of the pancreas. METHODS: Three hundred ninety-eight cases of cystadenomas of the pancreas were collected between 1984 and 1996 in 73 institutions of the French Surgical Association. Clinical presentation, radiologic evaluation, and surgical procedures were analyzed for 144 operated SCAs, 150 mucinous cystadenomas (MCAs), and 78 MCACs. The outcome of 372 operated patients and 26 nonoperated patients with SCA was analyzed. RESULTS: Cystadenomas represented 76% of all primary pancreatic cystic tumors (398/522). An asymptomatic tumor was discovered in 32% of patients with SCA, 26% of those with MCA, and 13% of those with MCAC. The tumor was located in the head or uncinate process of the pancreas in 38% of those with SCA, 27% of those with MCA, and 49% of those with MCAC. A communication between the cyst and pancreatic duct was discovered in 0.6% of those with SCA, 6% of those with MCA, and 10% of those with MCAC. The main investigations were ultrasonography and computed tomography (94% for SCA, MCA, and MCAC), endosonography (34%, 28%, and 22% for SCA, MCA, and MCAC respectively), endoscopic retrograde cholangiopancreatography (16%, 14%, 22%), and cyst fluid analysis (22%, 31%, 35%). An accurate preoperative diagnosis of tumor type was proposed for 20% of those with SCA (144 cases), 30% of those with MCA, and 29% of those with MCAC. An atypical unilocular macrocyst was observed in 10% of SCA cases. The most common misdiagnosis for mucinous cystic tumors was pseudocyst (9% of MCAs, 15% of MCACs). Intraoperative frozen sections (126 cases) allowed a diagnosis according to definitive histologic examination in 50% of those with SCA and MCA and 62% of those with MCAC. For management, 93% of patients underwent surgery. Nonoperated patients (7%) had exclusively typical SCA. A complete cyst excision was performed in 94% of benign cystadenomas, with an operative mortality rate of 2% for SCA and 1.4% for MCA. Resection was possible in 74% of cases of MCAC. Mean follow-up of 26 patients with nonresected SCAs was 38 months, and no patients required surgery. For resected MCACs, the actuarial 5-year survival rate was 63%. CONCLUSIONS: Spiral computed tomography is the examination of choice for a correct prediction of tumor type. Endosonography may be useful to detect the morphologic criteria of small tumors. Diagnostic aspiration of the cyst allows differentiation of the macrocystic form of SCA (10% of cases) and the unilocular type of mucinous cystic neoplasm from a pseudocyst. Surgical resection should be performed for symptomatic SCAs, all mucinous cystic neoplasms, and cystic tumors that are not clearly defined. Conservative management is wholly justified for a well-documented SCA with no symptoms. An extensive resection is warranted for MCAC because the 5-year survival rate may exceed 60%.     

Preoperative evaluation of thyroid nodules with 18FDG-PET/CT

BACKGROUND: Fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography ((18)FDG-PET/CT) has become an important tool in the postoperative management of de-differentiated thyroid cancer. The utility of this imaging modality in the preoperative assessment of thyroid nodules is unclear. This study was designed to determine whether (18)FDG-PET/CT improves the preoperative diagnosis of thyroid nodules. METHODS: A total of 31 patients with 48 lesions underwent fine-needle aspiration and (18)FDG-PET/CT before surgical resection of thyroid nodules. PET/CT images were obtained 1 hour after intravenous administration of (18)FDG. Standard uptake values were calculated for regions of increased (18)FDG uptake. CT scans were evaluated to identify thyroid pathology. Final pathologic diagnoses were compared with PET/CT findings. RESULTS: Fifteen of 48 lesions were malignant and 33 were benign. Nine of 15 malignant lesions were (18)FDG-avid (sensitivity 60%). Thirty of 33 benign lesions were (18)FDG-cold (specificity 91%). Positive and negative predictive values were 75% and 83%, respectively. CONCLUSIONS: (18)FDG-PET/CT provides a high negative predictive value for malignancy, making this a potentially useful tool in the evaluation of thyroid nodules with indeterminate fine-needle aspiration. However further studies with larger sample sizes are needed to determine the true efficacy of this test.     

Positron emission tomographic imaging with fluorodeoxyglucose isefficacious in evaluating malignant pulmonary disease

OBJECTIVE: Positron emission tomography (PET), when used with the intravenously administered radiopharmaceutical F-18 fluorodeoxyglucose (FDG), has the potential to help in the evaluation of patients with lung cancer because the radiopharmaceutical is concentrated by metabolically active cells. We conducted a retrospective study of PET-FDG in 96 patients evaluated at our institution over the past 2 years for suspected primary pulmonary neoplasms. PET-FDG results were compared with the findings of computed tomographic scans on the same patients. All patients underwent surgical exploration with or without resection of the malignant tumors. Sites of potential malignancy were subjected to biopsy and/or excision, with subsequent pathologic evaluation. RESULTS: A total of 96 patients with suspected or proven primary pulmonary malignant disease were evaluated. Sixty-six patients had histologically confirmed malignant tumors, and 30 had benign masses histologically. PET-FDG had an accuracy of detecting malignancy in pulmonary lesions of 92% (sensitivity 97%; specificity 89%). A total of 111 surgically sampled sites were from lymph nodes. PET-FDG was accurate in predicting the malignancy of nodes in 91% of instances, whereas computed tomography was correct in 64%. The sensitivity, specificity, and predictive accuracy of PET in detecting metastatic lymphadenopathy in mediastinal lymph nodes were 98%, 94%, and 95%, respectively. PET-FDG also changed the M stage in 8 (12%) patients (6 with and 2 without metastases). The 6 malignant (positive) lesions were correctly identified by PET-FDG, and the 2 without tumor were accurately predicted as benign (negative). CONCLUSION: These initial results suggest that PET-FDG is highly accurate in identifying and staging lung cancer. PET-FDG also appears to be more accurate in detecting metastatic mediastinal lymphadenopathy than computed tomographic scan.     

Surgical management of intraductal papillary mucinous tumor of the pancreas

BACKGROUND: Intraductal papillary mucinous tumor (IPMT) is a type of pancreatic cystic neoplasm. IPMT consists of intraductal papillary mucinous adenoma (benign IPMT) and intraductal papillary mucinous carcinoma (malignant IPMT). Preoperative diagnosis of malignancy is difficult; the invasiveness and metastatic character are not well known. The purpose of the study was to evaluate the optimal diagnostic and therapeutic strategy of IPMT. METHODS: Medical charts of 38 patients with final diagnosis of IPMT in Kyoto University Hospital were retrospectively reviewed. Preoperative imaging, mode of operation, and clinical and histopathologic findings were analyzed. RESULTS: In 38 IPMTs, imaging of localization was correct in 82% by computed tomography, 90% by ultrasonography, 70% by endoscopic retrograde cholangiopancreatography, 100% by magnetic resonance cholangiopancreatography, and 100% by endoscopic ultrasonography. Evaluation of malignancy by endoscopic ultrasonography resulted in sensitivity and specificity of 81% and 78%, respectively. Pylorus-preserving pancreaticoduodenectomy was preferably performed in 20 of 38 patients with IPMT. Twenty-two patients had histologically malignant disease. Half of them had an invasive component in the adjacent stroma. One case of malignant IPMT showed lymph node metastasis, and the patient had no recurrence after pancreaticoduodenectomy with regional lymphadenectomy. No case was diagnosed as margin positive; however, 27% showed a dysplasia with atypia in the epithelial cells of the cut edge of the pancreas. One patient with negative atypia at the cut edge of the pancreas developed a recurrent tumor in the remnant pancreas. CONCLUSIONS: The preoperative diagnosis of malignancy is difficult, and 50% of malignant IPMT showed an invasive component. Thus, radical resection of the pancreas with regional lymph node dissection should be the choice of treatment. Lymph node metastasis and intraductal distant invasion should be carefully managed in the surgical treatment of these lesions.     

Cystic tumors of the pancreas. New clinical, radiologic, and pathologic observations in 67 patients.

Within a 12-year period we treated 67 patients (49 women, 18 men; mean age, 61 years) with cystic neoplasms of the pancreas, including 18 serous cystic adenomas, 15 benign mucinous cystic neoplasms, 27 mucinous cystadenocarcinomas, 3 papillary cystic tumors, 2 cystic islet cell tumors, and 2 cases of mucinous ductal ectasia. Mean tumor size was 6 cm (2 to 16 cm). In 39% the patients had no symptoms, and in 37% the lesions had been misdiagnosed as a pseudocyst. Computed tomography was useful for detection, for distinguishing the microcystic subgroup of serous cystadenoma, and for showing rim calcification (all 7 cases were malignant) but was not reliable for distinguishing neoplasm from pseudocyst, serous from mucinous tumors, or benign from malignant. Arteriography showed hypervascularity in 4 of 10 serous adenomas, 3 of 11 mucinous carcinomas, and 1 of 1 papillary cystic tumors. Endoscopic pancreatography showed no communication with the cyst cavity in 37 of 37 cases of cystic neoplasms but opacified the ectatic ducts in 2 of 2 cases of mucinous ductal ectasia. Stenosis or obstruction of the pancreatic duct indicated cancer. The tumor was resected by distal pancreatectomy in 25 patients, by proximal resection in 29, and by total pancreatectomy in one, with no operative deaths. Forty-four per cent of the tumors were malignant. In 10 cases the tumor was unresectable because of local extension or distant metastases, and those patients died at a mean of 4 months. Seventy-five per cent of those resected for cure are alive without evident recurrence. Because the epithelial lining of the tumor was partially (5% to 98%) absent in 40% to 72% of cases of the major tumor types, and the mucinous component comprised only about 65% of mucinous cystadenoma lining, misdiagnoses on frozen and even permanent sections were made. Mitoses and histologic solid growth correlated with malignancy. Neuroendocrine elements were seen in 87% of benign and 47% of malignant mucinous tumors. It is recommended that the terms macrocystic and microcystic be abandoned in favor of the histologic designations serous and mucinous. Incomplete examination of the cyst wall can be misleading, however. It is suggested that mucinous ductal ectasia be recognized separately from cystic tumors and that all of these lesions be resected, with the possible exception of asymptomatic confirmed serous cystadenomas.     

Duodenal-preserving resection of the head of the pancreas and pancreatic head resection with second-portion duodenectomy for benign lesions,low-grade malignancies,and early carcinoma involving the periampullary region

HYPOTHESIS: Duodenal-preserving resection of the head of the pancreas (DPRHP) and pancreas head resection with segmental duodenectomy (PHRSD) can be alternatives to standard pancreaticoduodenectomy for benign periampullary lesions. DESIGN: Retrospective analysis of patients requiring surgery for benign and borderline malignant tumors of the periampullary region. SETTING: Tertiary care referral center. PATIENTS: Duodenal-preserving resection of the head of the pancreas (n = 8) and PHRSD (n = 7) were performed in 15 patients with a preoperative diagnosis of benign and borderline malignant tumors of the periampullary region (ie, 11 pancreas head lesions [2 intraductal papillary mucinous tumors, 4 serous cystadenomas, 2 insulinomas, 1 epidermal cyst, 1 metastatic renal cell carcinoma, 1 nonfunctioning islet cell tumor/parapaillary] and 4 duodenal lesions [3 adenomas and 1 adenocarcinoma]). MAIN OUTCOME MEASURES: Surgical factors (operation time and blood loss), postoperative complication, postoperative pancreatic insufficiency (eg, development of diabetes mellitus and steatorrhea or elevated stool elastase values), weight change, and recurrence of disease. RESULTS: No differences were noted in the mean operation time and estimated blood loss between the 2 procedures. Major postoperative complication constituted the following: bile duct stricture (n = 1) in DPRHP and delayed gastric emptying (n = 1) and postoperative bleeding (n = 1) in PHRSD. Newly developed diabetes mellitus occurred in 1 patient. Exocrine pancreatic insufficiency (steatorrhea) was observed in 1 patient after PHRSD. Patients with early duodenal carcinoma and intraductal papillary mucinous tumors with a borderline malignancy are still alive without evidence of recurrence. There was no hospital or long-term mortality. CONCLUSIONS: Duodenal-preserving resection of the head of the pancreas is recommended first for a benign or low-grade, early malignant pancreatic head lesion; PHRSD can be an option for a lesion of the ampullary-parapapillary duodenal area as well as the pancreatic head. Duodenal-preserving resection of the head of the pancreas can be converted to PHRSD if ischemia of the second portion of the duodenum occurs. We found benign periampullary lesions could be conservatively treated with DPRHP and PHRSD, which could substitute for classic pancreaticoduodenectomy.     

Fluorodeoxyglucose positron emission tomography improves preoperative staging of resectable lung metastasis

OBJECTIVE: F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) is now a procedure of proven clinical value in the staging of primary lung cancer. This study evaluated the role of PET in the preoperative assessment of resectable lung metastases. METHODS: Eighty-six patients with previously treated malignancy and proven or suspected lung metastases, deemed resectable at computed tomography scan, were investigated with 89 preoperative PET procedures. Primary tumor sites were: gastrointestinal in 32 cases, sarcoma in 13, urologic in 14, breast in 8, head and neck in 7, gynecologic in 5, thymus in 5, other in 5. Seventy lung resections were performed in 68 patients of whom only 54 proved to be lung metastasis, 7 were primary lung tumors, and 9 were benign lesions. RESULTS: In 19 cases (21%) lung surgery was excluded on the basis of PET scan results due to extrapulmonary metastases (11 cases), primary site recurrence (2), mediastinal adenopathy (2), or benign disease (4). All mediastinal node metastases (7 cases) were detected by PET with a sensitivity, accuracy, and negative predictive value for mediastinal staging of 100%, 96%, and 100%, respectively, versus 71%, 92%, and 95% of the computed tomography scan. In the group of patients who underwent lung resection, PET sensitivity for detection of lung metastasis was 87%. CONCLUSIONS: PET scan proved to be a valuable staging procedure in patients with clinically resectable lung metastasis and changed the therapeutic management in a high proportion of cases.     

Positron emission tomography does not add to computed tomography for the diagnosis and staging of pancreatic cancer

BACKGROUND: Positron emission tomography (PET) has been proposed for pancreatic cancer diagnosis and staging. METHODS: 112 patients with suspected pancreatic cancer underwent 18F-fluoro-2-deoxy-D-glucose gamma camera PET and computed tomography (CT), of whom 62 also had laparoscopic ultrasonography and 70 underwent abdominal exploration for potential resection. The final diagnosis was malignancy in 78 and benign disease in 34 patients (25 with chronic pancreatitis). RESULTS: The diagnostic sensitivity and specificity for PET were 73 and 60% compared to 89 and 65% for CT respectively (Cohen's kappa = 0.59). In 30 patients CT was equivocal with cancer in 14 and benign disease in 16. PET correctly diagnosed 13 of these patients (cancer in 6 and benign disease in 7), interpreted 4 as equivocal (cancer in 3 and benign disease in 1) but was incorrect in the remaining 13 patients (cancer in 5 and benign disease in 8). The sensitivity and specificity for detecting small volume metastatic disease were 20 and 94% for CT and 22 and 91% for PET, respectively. CONCLUSION: PET had a similar accuracy to that of CT for imaging pancreatic cancer but it did not provide any additional information in patients with equivocal CT findings and currently would seem of little benefit for the staging of pancreatic cancer.     

Positron emission tomography imaging of musculoskeletal tumors in the shoulder girdle

The shoulder girdle presents unique features for the preoperative planning of musculoskeletal tumors. This is the first trial to evaluate positron emission tomography (PET) analysis for preoperative planning in shoulder girdle tumors. Fifty-two patients were examined with fluorine 18 fluoro-2-deoxy-D-glucose (FDG)-PET and/or alpha-methyltyrosine (FMT)-PET. Imaging findings were visually inspected in conjunction with computed tomography and/or magnetic resonance imaging, and standardized uptake values (SUVs) were generated. FDG-PET may be useful for the detection of malignant tumors and screening for metastatic spread, with the qualitative assessment of heterogeneous biologic activity providing a correct approach for biopsy. The mean SUVs for malignant tumors were significantly higher than those for benign lesions. However, a useful cutoff SUV was not found in either FDG- or FMT-PET for differentiating malignant from benign tumors from receiver operating characteristic curve analysis. SUVs on FDG- and FMT-PET may merely be limited to differentiating malignant from benign tumors in the shoulder girdle.     

Telomerase activity is a useful marker to distinguish malignant pancreatic cystic tumors from benign neoplasms and pseudocysts

BACKGROUND: Pancreatic serous cystadenoma, mucinous cystic neoplasms, ductal adenocarcinoma with cystic change, and pseudocysts are a spectrum of pancreatic cystic lesions. Their management strategy and prognosis are extremely diverse. Imaging study, cytology, and analysis of the tumor markers of cyst fluid are not always reliable in differentiation of these disease entities. MATERIALS AND METHODS: Fifteen patients with pancreatic cystic neoplasms (including six mucinous cystadenocarcinomas, two mucinous cystic neoplasms with borderline malignancy, two mucinous cystadenomas, and five serous cystadenomas), 4 patients with pancreatic ductal adenocarcinomas with cystic change, and 10 patients with pseudocysts were studied. Echo-guided or computed tomography-guided biopsies of pancreatic cystic lesions and their normal counterparts were conducted on all patients prior to operation or other management. The specimens were assayed for telomerase activity by using TRAP (telomere repeat amplification protocol). The level of telomerase activity in each specimen was semiquantitated as strong, moderate, weak, and none. The final diagnoses were made from histopathological examination of surgically resected or biopsied specimens. The efficacy of telomerase activity as a tumor marker to predict malignancy of pancreatic cystic lesions was evaluated. RESULTS: Three of the four pancreatic ductal adenocarcinomas with cystic change had strong or moderate telomerase activity; four of the six mucinous cystadenocarcinomas had moderate or weak telomerase activity; one of the two mucinous cystadenomas with borderline malignancy had weak telomerase activity; and none of their normal counterparts had detectable telomerase activity. In contrast, none of the two mucinous cystadenomas, five serous cystadenomas, and 10 pseudocysts had detectable telomerase activity. Based on these results, the sensitivity of telomerase activity for prediction of malignancy or premalignancy of pancreatic cystic lesions was 67%, the specificity was 100%, and the positive and negative predictive values were 1.0 and 0.81, respectively. The overall accuracy was 86%. CONCLUSIONS: The differential expressions of telomerase activity have been detected specifically in malignant and premalignant pancreatic cystic tumors, but not in benign cystic neoplasms or pseudocysts. The implications of these results are that telomerase activation takes part in the malignant transformation of pancreatic cystic neoplasms and that telomerase activity is a useful marker to distinguish malignant pancreatic cystic tumors from benign neoplasms and pseudocysts.     

Systematic review of the utility of 18-FDG PET in the preoperative evaluation of IPMNs and cystic lesions of the pancreas

BackgroundThe aim of this systematic review is to assess the role of 18-fluorodeoxyglucose positron emission tomography in the preoperative evaluation of intraductal papillary mucinous neoplasms and cystic lesions of the pancreas.MethodsA computerized PubMed search was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to identify studies evaluating positron emission tomography in the preoperative evaluation of pancreatic cystic lesions.ResultsA total of 14 studies evaluated the role of 18-fluorodeoxyglucose positron emission tomography/positron emission tomography-computed tomography, 9 of which evaluated only intraductal papillary mucinous neoplasms and 5 evaluated all pancreatic cystic lesions, including intraductal papillary mucinous neoplasms. Pooled analysis was carried out for studies evaluating intraductal papillary mucinous neoplasms only and studies evaluating all cystic lesions. Imaging with 18-fluorodeoxyblucose positron emission tomography had a positive predictive value, negative predictive value, sensitivity, specificity, and accuracy of 90%, 91%, 85%, 95%, and 91% in identifying malignancy (defined as either invasive and/or high-grade dysplasia) in intraductal papillary mucinous neoplasms and a positive predictive value, negative predictive value, sensitivity, specificity, and accuracy of 85%, 81%, 79%, 86%, and 88% in identifying malignancy in other cystic lesions. Pooled analysis reported the positive predictive value, negative predictive value, sensitivity, specificity, and accuracy of Sendai consensus guidelines (SCG) criteria as 69%, 69%, 68%, 55%, and 58%. The Fukuoka consensus guidelines (FCG) only had sensitivity, specificity, and accuracy reported as 61%, 52%, and 52%, respectively.ConclusionThe 18-fluorodeoxyblucose positron emission tomography had a high degree of accuracy of detecting malignancy in intraductal papillary mucinous neoplasm and cystic lesion of the pancreas. Comparison of the utility of positron emission tomography with the Fukuoka consensus guidelines and the Sendai consensus guidelines suggest that positron emission tomography is superior to present guidelines in detecting malignant intraductal papillary mucinous neoplasm and cystic lesion of the pancreas. Further studies in larger patient cohorts may be required to corroborate these findings and to determine the place of positron emission tomography in the management of intraductal papillary mucinous neoplasm and cystic lesions of the pancreas.     

Duodenum-preserving total pancreatic head resection for cystic neoplasm—a limited but cancer-preventive procedure

Background Cystic neoplastic lesions of the pancreas are found in up to 10% of all pancreatic lesions. A malignant transformation of cystic neoplasia is observed in intraductal papillary mucinous tumor (IPMN) lesions in 60% and in mucinous cystic tumor (MCN) lesions in up to 30%. For cystic neoplasia located monocentrically in the pancreatic head and that do not have an association with an invasive pancreatic cancer, the duodenum-preserving total head resection has been used in recent time as a limited surgical procedure. Patients An indication to duodenum-preserving total pancreatic head resection is considered for patients who do not have clinical signs of an advanced cancer in the lesion and who have main-duct IPMN and monocentric MCN lesions. In 104 patients with cystic neoplastic lesions in the Ulm series, 32% finally had a carcinoma in situ or an advanced pancreatic cancer. The application of a duodenum-preserving total pancreatic head resection in patients with asymptomatic cystic lesion is based on the size of the tumor and the tumor relation to the pancreatic ducts. For patients who have preoperatively clinical signs of malignancy, a Kausch–Whipple type of oncologic resection is recommended. Results Duodenum-preserving total pancreatic head resection is used in several modifications. The surgical procedure is a limited pancreatic head resection which necessitates segmental resection of the peripapillary duodenum. Hospital mortality is very low; in most published series it is 0%. The long-term outcome is determined by completeness of resection for both—benign and malignant—entities. Careful evaluation of the frozen section results has a pivotal role for intraoperative decision making. Conclusion A duodenum-preserving total pancreatic head resection is a limited surgical procedure for patients who suffer a local monocentric, cystic neoplastic lesion in the pancreatic head. Absence of an advanced pancreatic cancer and completeness of extirpation of the benign tumor determine the long-term outcome. In regards to the location of the lesion in the pancreatic head, several modifications have been applied with low hospital morbidity and mortality below 1%.     

Non-neoplastic cystic and cystic-like lesions of the pancreas: may mimic pancreatic cystic neoplasms

BACKGROUND: Cystic lesions of the pancreas consist of a broad range of pathological entities. With the exception of the pancreatic pseudocyst, these are usually caused by pancreatic cystic neoplasms. Non-neoplastic pancreatic cystic and cystic-like lesions are extremely rare. In the present article, the surgical experience with these unusual entities over a 14-year period is reported. METHODS: Between 1991 and 2004, all patients who underwent surgical exploration for a cystic lesion of the pancreas were retrospectively reviewed. Patients with a pancreatic pseudocyst were excluded. There were 106 patients of whom 8 (7.5%) had a final pathological diagnosis consistent with a non-neoplastic pancreatic cystic or cystic-like lesion, including 3 patients with a benign epithelial cyst, 2 with a pancreatic abscess (one tuberculous and one foreign body), 2 with mucous retention cysts and 1 with a mucinous non-neoplastic cyst. These eight patients are the focus of this study. RESULTS: There were six female and two male patients with a median age of 61.5 years (range, 41-71 years). All the patients were of Asian origin including seven Chinese and one Indian. Four of the patients were asymptomatic and their pancreatic cysts were discovered incidentally on radiological imaging for other indications. All the patients underwent preoperative radiological investigations, including ultrasonography, computed tomography or magnetic resonance imaging, which showed a cystic lesion of the pancreas. Three patients, all of whom were symptomatic, were diagnosed preoperatively with a malignant cystic neoplasm on the basis of radiological imaging. Two patients were eventually found to have a pancreatic abscess, one tuberculous and the other, secondary to foreign body perforation. The third patient was found on final histology to have chronic pancreatitis with retention cysts. The remaining five patients had a preoperative diagnosis of an indeterminate cyst; on pathological examination, they were found to have a benign epithelial (congenital) cyst (n = 3), retention cyst (n = 1) and mucinous non-neoplastic cyst (n = 1). At a median follow up of 20 months (range, 3-34 months), none of the patients had any evidence of recurrent disease. CONCLUSION: Non-neoplastic cystic and cystic-like lesions of the pancreas are rare causes of pancreatic cystic lesions that are generally benign and do not require surgery when asymptomatic. However, despite advances in diagnostic investigations such as endoscopic ultrasound with fluid aspirate and magnetic resonance imaging, the preoperative diagnosis remains unreliable. Hence, the challenge for all clinicians is to recognize these lesions preoperatively and to avoid 'unnecessary' surgery.     

Risk of Malignancy in Resected Cystic Tumors of the Pancreas ≤3 cm in Size: Is it Safe to Observe Asymptomatic Patients? A Multi-institutional Report

Recent international consensus guidelines propose that cystic pancreatic tumors less than 3 cm in size in asymptomatic patients with no radiographic features concerning for malignancy are safe to observe; however, there is little published data to support this recommendation. The purpose of this study was to determine the prevalence of malignancy in this group of patients using pancreatic resection databases from five high-volume pancreatic centers to assess the appropriateness of these guidelines. All pancreatic resections performed for cystic neoplasms ≤3 cm in size were evaluated over the time period of 1998–2006. One hundred sixty-six cases were identified, and the clinical, radiographic, and pathological data were reviewed. The correlation with age, gender, and symptoms (abdominal pain, nausea and vomiting, jaundice, presence of pancreatitis, unexplained weight loss, and anorexia), radiographic features suggestive of malignancy by either computed tomography, magnetic resonance imaging, or endoscopic ultrasound (presence of solid component, lymphadenopathy, or dilated main pancreatic duct or common bile duct), and the presence of malignancy was assessed using univariate and multivariate analysis. Among the 166 pancreatic resections for cystic pancreatic tumors ≤3 cm, 135 cases were benign [38 serous cystadenomas, 35 mucinous cystic neoplasms, 60 intraductal papillary mucinous neoplasms (IPMN), 1 cystic papillary tumor, and 1 cystic islet cell tumor], whereas 31 cases were malignant (14 mucinous cystic adenocarcinomas and 13 invasive carcinomas and 4 in situ carcinomas arising in the setting of IPMN). A greater incidence of cystic neoplasms was seen in female patients (99/166, 60%). Gender was a predictor of malignant pathology, with male patients having a higher incidence of malignancy (19/67, 28%) compared to female patients (12/99, 12%; p < 0.02). Older age was associated with malignancy (mean age 67 years in patients with malignant disease vs 62 years in patients with benign lesions (p < 0.05). A majority of the patients with malignancy were symptomatic (28/31, 90%). Symptoms that correlated with malignancy included jaundice (p < 0.001), weight loss (p < 0.003), and anorexia (p < 0.05). Radiographic features that correlated with malignancy were presence of a solid component (p < 0.0001), main pancreatic duct dilation (p = 0.002), common bile duct dilation (p < 0.001), and lymphadenopathy (p < 0.002). Twenty-seven of 31(87%) patients with malignant lesions had at least one radiographic feature concerning for malignancy. Forty-five patients (27%) were identified as having asymptomatic cystic neoplasms. All but three (6.6%) of the patients in this group had benign disease. Of the patients that had no symptoms and no radiographic features, 1 out of 30 (3.3%) had malignancy (carcinoma in situ arising in a side branch IPMN). Malignancy in cystic neoplasms ≤3 cm in size was associated with older age, male gender, presence of symptoms (jaundice, weight loss, and anorexia), and presence of concerning radiographic features (solid component, main pancreatic duct dilation, common bile duct dilation, and lymphadenopathy). Among asymptomatic patients that displayed no discernable radiographic features suggestive of malignancy who underwent resection, the incidence of occult malignancy was 3.3%. This study suggests that a group of patients with small cystic pancreatic neoplasms who have low risk of malignancy can be identified, and selective resection of these lesions may be appropriate.