Intraoperative ultrasound and preoperative localization detects all occult insulinomas; discussion 1025-6

The Landmark Series: Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PNETs) comprise a heterogeneous group of neoplasms arising from pancreatic islet cells that remain relatively rare but are increasing in incidence worldwide. While significant advances have been made in recent years with regard to systemic therapies for patients with advanced disease, surgical resection remains the standard of care for most patients with localized tumors. Although formal pancreatectomy with regional lymphadenectomy is the standard approach for most PNETs, pancreas-preserving approaches without formal lymphadenectomy are acceptable for smaller tumors at low risk for lymph node metastases. Furthermore, observation of small, asymptomatic, low-grade PNETs is a safe, initial strategy and is generally recommended for tumors < 1 cm in size. In this Landmark Series review, we highlight the critical studies that have defined the surgical management of PNETs.

Homogenously isoattenuating insulinoma on biphasic contrast-enhanced computed tomography: Little benefits of diffusion-weighted imaging for lesion detection

The aim of the present study was to evaluate the diagnostic benefit of diffusion-weighted imaging (DWI) in the detection of homogenous isoattenuating insulinoma on biphasic contrast-enhanced computed tomography (CT) preoperatively and to determine which magnetic resonance (MR) sequences exhibited the best diagnostic performance. A total of 44 consecutive patients who underwent biphasic contrast-enhanced CT and conventional MR imaging (MRI), including DWI on a 3T scanner, were identified retrospectively. Apparent diffusion coefficient (ADC) values of insulinomas and the surrounding pancreatic parenchyma were compared using a Wilcoxon signed-rank test. Receiver operating characteristic analysis was used to compare the diagnostic accuracy of four randomized image sets [T2-weighted image (WI), axial T1WI, DWI and T2WI + DWI] for each reader. Axial T1-weighted MRI exhibited the highest relative sensitivity for each reader; DWI alone exhibited the lowest relative sensitivity and the lower inter-reader agreement. There was no significant difference in lesion detection between T2WI and T2WI + DWI image sets for each reader. The ADC values of the insulinoma were significantly lower compared with those of the surrounding parenchyma. In conclusion, DWI does not benefit the detection of homogenous isoattenuating insulinoma. Axial T1WI is the optimal pulse sequence. Quantitative assessment of the tumor ADC values may be a useful tool to characterize identified pancreatic neoplasms.

Imaging of secretory tumors of the gastrointestinal tract

Gastrointestinal secretory tumors, or gastroenteropancreatic neuroendocrine tumors, encompass a wide array of endocrine cell tumors. The significance of these tumors lies in their ability to alter physiology through hormone production as we well as in their malignant potential. Functioning tumors may present earlier due to symptomatology; conversely, non-functioning tumors are often diagnosed late as they reach large sizes, causing symptoms secondary to local mass effect. Imaging aids in the diagnosis, staging, and prognosis and provides key information for presurgical planning. Although most of these tumors are sporadic, some are associated with important syndromes and associations, knowledge of which is critical for patient management. In this article, we provide an overview of secretory and neuroendocrine tumors of the GI tract and pancreas.

Cross sectional and nuclear medicine imaging of pancreatic insulinomas

Insulinomas are rare neuroendocrine tumors which occur predominantly in the pancreas. Although majority of the insulinomas are benign, over-secretion of insulin by the tumor leads to debilitating hypoglycemic symptoms. The diagnosis is based on clinical and biochemical findings. After the diagnosis is made, the principal challenge lies in locating the tumor because most tumors are solitary and small in size. Locating the tumor is of paramount importance as complete surgical excision is the only curative treatment, and incomplete resection leads to persistence of symptoms. Different preoperative and intraoperative imaging techniques have been used with varying success rates for the insulinoma imaging. Besides localizing the tumor, imaging also helps to guide biopsy, detect metastatic lesions, and perform image-guided therapeutic procedures. This review will discuss the role of different Cross sectional and nuclear medicine imaging modalities in insulinomas.

Insulinoma Detection With MDCT: Is There a Role for Whole-Pancreas Perfusion?

OBJECTIVE

The purpose of this study is to investigate the role of whole-pancreas perfusion in detecting insulinomas with the use of MDCT.

MATERIALS AND METHODS

From January 2011 to December 2011, a total of 70 consecutive patients (33 men and 37 women; mean age, 46 years; range, 17-73 years) who underwent biphasic contrast-enhanced CT and whole-pancreas CT perfusion for suspected insulinomas were identified retrospectively. Patients were monitored for at least 3 years. Two radiologists who were blinded to the clinical and surgical data independently evaluated the images, first assessing only the biphasic contrast-enhanced CT images to detect tumor and assess diagnostic confidence on a 5-point scale. Next, perfusion parametric maps were evaluated and pancreatic perfusion parameters measured, and the presence of tumor was reidentified using a combination of the biphasic CT and perfusion image sets. A ROC curve was generated to compare the diagnostic accuracy of the two image sets.

RESULTS

The mean blood flow (BF) values of both the insulinomas and the insulinoma-harboring regions were statistically significantly higher (p < 0.01, for both) than the BF value of tumor-free pancreatic parenchyma. For the detection of insulinoma, biphasic CT had a sensitivity of 88.1%, a specificity of 85.7%, a positive predictive value of 91.1%, and a negative predictive value of 81.4%, whereas combined biphasic CT and perfusion had a sensitivity of 94.6%, a specificity of 94.7%, a positive predictive value of 96.7%, and a negative predictive value of 91.5%. The mean area under the ROC curve increased from 0.939 with biphasic CT to 0.999 with the addition of perfusion. Nine of 46 tumors (19.6%) for which findings were negative (n = 2) or indeterminate (n = 7) on biphasic CT were correctly diagnosed with the addition of perfusion.

CONCLUSION

The addition of pancreatic perfusion to biphasic contrast-enhanced CT may improve the detection of insulinomas.

Pancreatic neuroendocrine tumors: contemporary diagnosis and management

Pancreatic neuroendocrine tumors (PNETs) are neoplasms that arise from the hormone producing cells of the islets of Langerhans, also known as pancreatic islet cells. PNETs are considered a subgroup of neuroendocrine tumors, and have unique biology, natural history and clinical management. These tumors are classified as 'functional' or 'non-functional' depending on whether they release peptide hormones that produce specific hormone- related symptoms, usually in established patterns based on tumor subtype. This manuscript will review pancreatic neuroendocrine tumor subtypes, syndromes, diagnosis, and clinical management.

Imaging of pancreatic neoplasms

Ductal adenocarcinoma accounts for 85% to 90% of all solid pancreatic neoplasms, is increasing in incidence, and is the fourth leading cause of cancer-related deaths. There are currently no screening tests available for the detection of ductal adenocarcinoma. The only chance for cure in pancreatic adenocarcinoma is surgery. Imaging has a crucial role in the identification of the primary tumor, vascular variants, identification of metastases, disease response assessment to treatment, and prediction of respectability. Pancreatic neuroendocrine neoplasms can have a distinctive appearance and pattern of spread, which should be recognized on imaging for appropriate management of these patients.

Multiple Endocrine Neoplasia: Genetics and Clinical Management

Early diagnosis of multiple endocrine neoplasia (MEN) syndromes is critical for optimal clinical outcomes; before the MEN syndromes can be diagnosed, they must be suspected. Genetic testing for germline alterations in both the MEN type 1 (MEN1) gene and RET proto-oncogene is crucial to identifying those at risk in affected kindreds and directing timely surveillance and surgical therapy to those at greatest risk of potentially life-threatening neoplasia. Pancreatic, thymic, and bronchial neuroendocrine tumors are the leading cause of death in patients with MEN1 and should be aggressively considered by at least biannual computed tomography imaging.

The use of intraoperative ultrasound for diagnosis and stadiation in pancreatic head neoformations

The intraoperative staging of the pancreatic cancer is important to make a proper treatment. For this reason the intraoperative echography is playing an important role in the right treatment choice. The intraoperative echography, that can be performed with an open or laparoscopic probe, is used to confirm the preoperative diagnosis and assess the pancreatic cancer resecability. The intraoperative echography (IOUS) or laparoscopic intraoperative echography (LIOUS) are useful to identify the patients with a non resecable cancer and perform a faster neoadjuvant treatment. The LIOUS can also avoid an useless laparotomy. The aim of this study is to assess, both in our experience and in the cited literature, the concordance rate between the pancreatic cancer preoperative staging, performed with TC and MRI (when it is available), and intraoperative staging, performed with intraoperative laparotomic or laparoscopic echography.

MATERIAL AND METHODS

We have analyzed the treatment management of 34 patients, who were candidate to major surgery for suspected pancreatic head cancer and who underwent to intraoperative LIOUS or IOUS staging from 2001 to 2012.

RESULTS

LIOUS and IOUS have allowed to detect cases in which preoperative diagnosis, proved by CT and MRI, was not agreeing with intraoperative diagnosis (22 patients on 34, 64% discordance rate), avoiding the execution of a demolitive and uneseful surgery in order to guarantee the surveillance and life's quality of patients.

CONCLUSION

We suggest to perform in every patients undergone to pancreatic surgery an intraoperative ultrasound exam, to detect unresecable and unpredicted lesions.

Applications of intraoperative ultrasound in the treatment of complicated cases of acute and chronic pancreatitis and pancreatic cancer - own experience

Both acute and chronic inflammation of the pancreas often lead to complications that nowadays can be resolved using endoscopic and surgical procedures. In many cases, intraoperative ultrasound examination (IOUS) enables correct assessment of the extent of the lesion, and allows for safe surgery, while also shortening its length.

AIM OF THE RESEARCH

At the authors' clinic, intraoperative ultrasound is performed in daily practice. In this paper, we try to share our experiences in the application of this particular imaging technique.

RESEARCH SAMPLE AND METHODOLOGY

Intraoperative examination conducted by a surgeon who has assessed the patient prior to surgery, which enabled the surgeon to verify the initial diagnosis. The material presented in this paper includes 145 IOUS procedures performed during laparotomy due to lesions of the pancreas, 57 of which were carried out in cases of inflammatory process.

RESULTS AND CONCLUSIONS

IOUS is a reliable examination tool in the evaluation of acute inflammatory lesions in the pancreas, especially during the surgery of chronic, symptomatic inflammation of the organ. The procedure allows for a correct determination of the necessary scope of the planned surgery. The examination allows for the differentiation between cystic lesions and tumors of cystic nature, dictates the correct strategy for draining, as well as validates the indications for the lesion's surgical removal. IOUS also allows the estimation of place and scope of drainage procedures in cases of overpressure in the pancreatic ducts caused by calcification of the parenchyma or choledocholitiasis in chronic pancreatitis. In pancreatic cancer, IOUS provides a verification of the local extent of tumor-like lesions, allowing for the assessment of pancreatic and lymph nodes metastasis, and indicating the presence of distant and local metastases, including the liver. IOUS significantly improves the effectiveness of intraoperative BAC aspiration or drainage of fluid reservoirs.

Duodenum-preserving resection and Roux-en-Y pancreatic jejunostomy in benign pancreatic head tumors

This study was conducted to explore the feasibility of partial pancreatic head resection and Roux-en-Y pancreatic jejunostomy for the treatment of benign tumors of the pancreatic head (BTPH). From November 2006 to February 2009, four patients (three female and one male) with a mean age of 34.3 years (range: 21-48 years) underwent partial pancreatic head resection and Roux-en-Y pancreatic jejunostomy for the treatment of BTPH (diameters of 3.2-4.5 cm) using small incisions (5.1-7.2 cm). Preoperative symptoms include one case of repeated upper abdominal pain, one case of drowsiness and two cases with no obvious preoperative symptoms. All four surgeries were successfully performed. The mean operative time was 196.8 min (range 165-226 min), and average blood loss was 138.0 mL (range: 82-210 mL). The mean postoperative hospital stay was 7.5 d (range: 7-8 d). In one case, the main pancreatic duct was injured. Pathological examination confirmed that one patient suffered from mucinous cystadenoma, one exhibited insulinoma, and two patients had solid-pseudopapillary neoplasms. There were no deaths or complications observed during the perioperative period. All patients had no signs of recurrence of the BTPH within a follow-up period of 48-76 mo and had good quality of life without diabetes. Partial pancreatic head resection with Roux-en-Y pancreatic jejunostomy is feasible in selected patients with BTPH.

Insulinoma case series: Experience of a tertiary care center

BACKGROUND

Insulinomas are usually solitary; benign and encapsulated small lesions and majority of them measure <2 cm in diameter. They pose a challenge for pre-operative localization. Definitive treatment is surgical excision of the tumor. Intra-operative ultrasonography (IOUS), transhepatic portal venous sampling (THPVS) and positron emission tomography (PET) scan can be done for tumors not localized by conventional imaging modalities.

MATERIALS AND METHODS

A retrospective study of patients diagnosed with insulinoma during the period 2004-2012 (8 years) was done. Biochemical diagnostic criteria used were plasma concentrations of glucose <55 mg/dl with corresponding insulin level >3.0 μU/ml (18 pmol/L) and C-peptide of >0.6 ng/ml (0.2 nmol/L). The localization of the tumor was done by various modalities namely computed tomography (CT), magnetic resonance imaging (MRI), IOUS, PET and portal venous sampling. The initial localizing technique in most of these patients were CT or MRI imaging, or both and those who were not localized by the above modalities were subjected to PET CT or THPVS or intra-operative ultrasound depending on the initial imaging results and patient's consent. All the modalities were not used in the same patient, but the modalities were decided as per the imaging results, patient's consent and affordability for the procedure.

RESULTS

Ninteen cases of insulinoma aged between 10 and 66 years, with a median age of 47 years were included in the analysis. There were 10 males and nine females. Eighty-three percent of patients presented with pre-prandial hypoglycemia (n = 15). Different modalities were employed for pre-operative localization of these patients out of which 5 (26.31%) cases were localized with CT, 5 (26.31) cases with MRI, 5 (26.31%) with THPVS, 1 (5.26%) case with PET CT, 3 (15.78%) of them could not be localized out of which 2 (10.52%) were localized by IOUS and 1 (5.26%) case the lesion could not be localized. Among 19 cases, 12 underwent surgery out of which one patient underwent distal pancreatectomy as tumor was not localized; eight underwent laparoscopic enucleation; three of them required intra-operative exploration and seven of them were not operated, as they did not give consent for surgery. In all the cases, the size of the insulinoma ranged between 1 and 2 cm.

CONCLUSION

We report our experience with 19 cases of insulinoma and analyze the role of pre- and intra-operative imaging modalities in the surgical management of insulinomas. Most of our cases were symptomatic, and the most common presentation was with pre-prandial hypoglycemia. THPVS, PET scan and intra-operative ultrasound added to diagnostic sensitivity in some cases not localized by CT or MRI.

Management of endocrine disease: a clinical update on tumor-induced hypoglycemia

Tumor-induced hypoglycemia (TIH) is a rare clinical entity that may occur in patients with diverse kinds of tumor lineages and that may be caused by different mechanisms. These pathogenic mechanisms include the eutopic insulin secretion by a pancreatic islet β-cell tumor, and also the ectopic tumor insulin secretion by non-islet-cell tumor, such as bronchial carcinoids and gastrointestinal stromal tumors. Insulinoma is, by far, the most common tumor associated with clinical and biochemical hypoglycemia. Insulinomas are usually single, small, sporadic, and intrapancreatic benign tumors. Only 5-10% of insulinomas are malignant. Insulinoma may be associated with the multiple endocrine neoplasia type 1 in 4-6% of patients. Medical therapy with diazoxide or somatostatin analogs has been used to control hypoglycemic symptoms in patients with insulinoma, but only surgical excision by enucleation or partial pancreatectomy is curative. Other mechanisms that may, more uncommonly, account for tumor-associated hypoglycemia without excess insulin secretion are the tumor secretion of peptides capable of causing glucose consumption by different mechanisms. These are the cases of tumors producing IGF2 precursors, IGF1, somatostatin, and glucagon-like peptide 1. Tumor autoimmune hypoglycemia occurs due to the production of insulin by tumor cells or insulin receptor autoantibodies. Lastly, massive tumor burden with glucose consumption, massive tumor liver infiltration, and pituitary or adrenal glands destruction by tumor are other mechanisms for TIH in cases of large and aggressive neoplasias.

Comparison of two low-dose calcium infusion schedules for localization of insulinomas by selective pancreatic arterial injection with hepatic venous sampling for insulin

OBJECTIVE

Localization of small insulinomas may be difficult. Selective pancreatic arterial injection of calcium with hepatic venous insulin measurement (SACST) has been used for this purpose, but can rarely cause hypoglycaemia. Two low-dose concentrations of calcium, 0·25 and 0·1 of the usual concentration used for the test, have been compared for sensitivity of localization and safety.

DESIGN

Selective pancreatic arterial injection of calcium with hepatic venous insulin measurement was performed at calcium concentrations of 0·0025 (Protocol A) and 0·00625 (Protocol B) mEq calcium per kg. The standard concentration is 0·025 mEq/kg.

PATIENTS

Twenty one successive patients with biochemical evidence of insulinoma were studied.

RESULTS

Using surgical localization as the gold standard, Protocol A had a sensitivity of 91% and Protocol B 75% for correct localization. The false-positive localization rate was 16%. No hypoglycaemia was observed. These results compare favourably with published data using the standard calcium concentration. Selective pancreatic arterial injection of calcium with hepatic venous insulin measurement was superior to localization by noninvasive imaging; in seven cases, SACST was correct when conventional imaging was negative (five) or false positive (two).

CONCLUSION

Low concentrations of calcium are effective and safe when performing SACST for localization of insulinoma.

The surgical management of insulinomas in children

PURPOSE

Insulinomas are rare pediatric tumors for which optimal localization studies and management remain undetermined. We present our experience with surgical management of insulinomas during childhood.

METHODS

A retrospective review was performed of patients who underwent surgical management for an insulinoma from 1999 to 2012.

RESULTS

The study included eight patients. Preoperative localization was successful with abdominal ultrasound, abdominal CT, endoscopic ultrasound, or MRI in only 20%, 28.6%, 40%, and 50% of patients, respectively. Octreotide scan was non-diagnostic in 4 patients. For diagnostic failure, selective utilization of 18-Fluoro-DOPA PET/CT scanning, arterial stimulation/venous sampling, or transhepatic portal venous sampling were successful in insulinoma localization. Intraoperatively, all lesions were identified by palpation or with the assistance of intraoperative ultrasound. Surgical resection using pancreas sparing techniques (enucleation or distal pancreatectomy) resulted in a cure in all patients. Postoperative complications included a pancreatic fistula in two patients and an additional missed insulinoma in a patient with MEN-1 requiring successful reoperation.

CONCLUSIONS

Preoperative tumor localization may require many imaging modalities to avoid unsuccessful blind pancreatectomy. Intraoperative palpation with the assistance of ultrasound offers a reliable method to precisely locate the insulinoma. Complete surgical resection results in a cure. Recurrent symptoms warrant evaluation for additional lesions.

Pancreatic neuroendocrine tumors: radiographic calcifications correlate with grade and metastasis

BACKGROUND

Studies to identify preoperative prognostic variables for pancreatic neuroendocrine tumor (PNET) have been inconclusive. Specifically, the prevalence and prognostic significance of radiographic calcifications in these tumors remains unclear.

METHODS

From 1998 to 2009, a total of 110 patients with well-differentiated PNET underwent surgical resection at our institution. Synchronous liver metastases present in 31 patients (28%) were addressed surgically with curative intent. Patients with high-grade PNET were excluded. The presence of calcifications in the primary tumor on preoperative computed tomography was recorded and correlated with clinicopathologic variables and overall survival.

RESULTS

Calcifications were present in 16% of patients and were more common in gastrinomas and glucagonomas (50%), but never encountered in insulinomas. Calcified tumors were larger (median size 4.5 vs. 2.3 cm, P=0.04) and more commonly associated with lymph node metastasis (75 vs. 35%, P=0.01), synchronous liver metastasis (62 vs. 21%, P<0.01), and intermediate tumor grade (80 vs. 31%, P<0.01). On multivariate analysis of factors available preoperatively, calcifications (P=0.01) and size (P<0.01) remained independent predictors of lymph node metastasis. Overall survival after resection was significantly worse in the presence of synchronous liver metastasis (5-year, 64 vs. 86%, P=0.04), but not in the presence of radiographic calcifications.

CONCLUSIONS

Calcifications on preoperative computed tomography correlate with intermediate grade and lymph node metastasis in well-differentiated PNET. This information is available preoperatively and supports the routine dissection of regional lymph nodes through formal pancreatectomy rather than enucleation in calcified PNET.

The role of interventional venous sampling in localising neuroendocrine tumours

PURPOSE OF REVIEW

This review focuses on the role of interventional venous sampling in the diagnosis and localization of neuroendocrine tumours (NETs), and its role in relation to conventional and novel imaging techniques.

RECENT FINDINGS

Imaging of NETs has evolved together with advances in imaging technology. Imaging localization plays an important role in the subsequent management of these tumours. This article provides an overview of the application of venous sampling in the localization of NETs, presented with current evidence to support its continued role in the diagnostic work-up of pituitary, parathyroid, pancreatic, adrenal and ovarian endocrine disease.

SUMMARY

Interventional venous sampling continues to be a highly sensitive modality in the localization of NETs. Although significant advances in noninvasive anatomic and functional imaging modalities have reduced the reliance of this well established technique, the latest literature continues to support its important role in the diagnostic armament of these unique and rare tumours.

Laparoscopic ultrasound enhances diagnosis and localization of insulinoma in pancreatic head and neck for laparoscopic surgery with satisfactory postsurgical outcomes

This study explored the value of laparoscopic ultrasonography (LUS) for tumor localization in laparoscopic pancreatic surgery of insulinomas, especially for tumors located at anatomically unfavorable positions. Twenty-eight patients with insulinomas were enrolled in this study between July 2007 and March 2009. Various image examinations were performed preoperatively. An iU22 ultrasound system equipped with a 5.0-9.0 MHz transducer was used for LUS. The tumor localization and postsurgical outcomes were evaluated. Intraoperative LUS precisely localized 33 insulinomas in 26 of 28 patients, whereas the preoperative imaging studies detected 27 of 33 (82%) tumors. No definite tumor in the pancreas and extra-pancreatic organs was identified in two patients by both preoperative and intraoperative imaging examinations. Of 33 tumors, 32 (97%) were localized in the pancreas (14 in the head and neck, 18 in the body and tail), whereas one (3%) was found in the duodenal ligament. Successful laparoscopic resection of insulinoma was performed in 21 of 26 patients, including resection of 11 tumors located in the head and neck of the pancreas. Five patients required conversion to open surgery. All insulinomas were benign with a mean size 13.8 mm. Four patients had pancreatic-related complications that spontaneously healed within 3 weeks after surgery. The median hospital stay was 8.5 days. Our study demonstrates that laparoscopic pancreatic resection under the guidance of advanced LUS is not only feasible and safe for tumors located at the body and tail but also for tumors located at the head and neck of the pancreas.

Surgery for gastroenteropancreatic neuroendocrine tumors (GEPNETS)

The only therapy with the potential for complete cure of patients with gastroenteropancreatic neuroendocrine tumors is complete surgical excision. Surgical options per se are often dictated by the tumor's site of origin, degree of tumor burden, and overall health or debility of the individual patient. This article considers different options based on the type of tumor and site of origin.

Metabolic acidosis as a complication of intravenous dextrose administration in a patient with insulinoma

There are few cases published in literature in which the use of intravenous dextrose as treatment for an insulinoma resulted in a metabolic acidosis. This is due perhaps to the usual method of administration, which is usually at low concentrations, for limited periods or low volumes. We present the case of a woman with suspected insulinoma by laboratory findings in which an endogenous hyperinsulinism was observed. During hospitalization, the patient required a progressive increase of the glucose infusion to prevent severe hypoglycemia. Two days before surgery, the patient presented symptoms of malaise and muscle weakness and a metabolic acidosis with hypokalemia became apparent in the blood analysis. This metabolic imbalance was attributed to a long period of treatment with high volume of intravenous dextrose infusion. If large doses of dextrose are required in a patient with an insulinoma, then the possibility of a metabolic imbalance must be considered during the follow-up. When the suspicion of an insulinoma is high, and all the attempts of pre-operative localization fail, patients should be derived early to specialized centers with modern imaging techniques, so that surgery is not delayed, and this rare and threatening complication could be avoided.

Imaging techniques in pancreatic tumors

Conventional ultrasonography represents the first diagnostic imaging modality for the study of pancreatic tumors. Contrast-enhanced ultrasound has significantly improved the accuracy of first-line examination and may influence the choice of second-line investigations: multidetector computed tomography is considered the gold standard for studying pancreatic solid lesions and tumor staging, while MRI with magnetic resonance cholangiopancreatography allows better study of pancreatic cystic lesions and the ductal system. To definitely diagnose a pancreatic lesion, image-guided fine-needle-aspiration or biopsy are very often required. PET with 18-fluorodeoxyglucose, endoscopic ultrasound and intraoperative ultrasonography remain techniques often employed in the third line. This article reviews the imaging techniques generally used for diagnosing the main pancreatic tumors, and a work-up algorithm is finally proposed.

Laparoscopic surgery for benign lesions of the pancreas

BACKGROUND

Minimally invasive pancreatic surgery, although known to be feasible and safe, is still not considered a standard procedure. We report our experience with laparoscopic pancreatic surgery in a retrospective case series.

MATERIALS AND METHODS

Fifteen consecutive patients (3 male, 12 female) underwent primarily laparoscopic pancreatic surgery from February 2000 to June 2005. Histologically confirmed diagnoses were: neuroendocrine pancreatic tumors (n = 11), adult nesidioblastosis (n = 1), serous cystadenoma (n = 1), and pseudocysts due to chronic pancreatitis (n = 2).

RESULTS

Enucleation (n = 3) or left pancreatic resection with spleen preservation (n = 6) was performed laparoscopically in 9 patients. The mean (+/-standard deviation) operative time was 173 +/- 48 minutes (range, 120-250 minutes) and the mean postoperative hospital stay was 5.5 +/- 1.2 days (range, 5-8 days) for the laparoscopic cases. Conversion to open surgery was necessary in 6 patients because of: closeness of the lesion to the portal/mesenteric vein (n = 3), inadequate intraoperative tumor localization (n = 2), or stapler device dysfunction (n = 1). In these patients, open enucleation (n = 1), middle segment pancreatectomy (n = 2), left pancreatic resection (n = 2), and pylorus-preserving Whipple resection (n = 1) were performed. The mean operative time was 268 +/- 74 minutes (range, 150-360 minutes) with a mean postoperative hospital stay of 8 +/- 2 days (range, 6-10 days). Both operative time and hospital stay were significantly longer in patients with secondary open surgery compared to patients with successful laparoscopic operations.

CONCLUSION

Laparoscopic enucleation or distal pancreatectomy with spleen preservation for benign lesions located in the body or tail of the pancreas can be performed safely, with all the potential benefits of minimally invasive surgery. Preoperative tumor localization is of utmost importance to limit pancreatic mobilization and to avoid blind pancreatic resection and conversion to open surgery.

Parenchyma-sparing resections for pancreatic neoplasms

BACKGROUND/PURPOSE

In recent years there has been an increase in the indications for pancreatic resection of benign or low-grade malignant lesions, especially in young patients with long life expectancy. In this setting, patients may benefit from parenchyma-sparing resections in order to decrease the risk of development of exocrine/endocrine insufficiency.

METHODS

A review of the literature and authors experience was undertaken.

RESULTS

Parenchyma-sparing resections of the pancreas including enucleation, middle pancreatectomy (MP) and middle-preserving pancreatectomy are described. Short and long-term outcomes after surgery are analyzed with special regard to postoperative morbidity/mortality, and oncological and functional long-term results.

CONCLUSIONS

Parenchyma-sparing resections are safe and effective procedures for treatment of benign and low-grade malignant neoplasms. Despite a significant postoperative morbidity they are associated with good long-term functional and oncological results. Enucleation should preferentially be performed laparoscopically whenever possible.

Is intraoperative ultrasound (IOUS) still useful for the detection of liver metastases?

PURPOSE

To evaluate the clinical impact of intraoperative ultrasound (IOUS) in the detection of liver metastases during the years, as compared with those of other imaging modalities.

MATERIALS AND METHODS

All IOUS scans performed for detection of liver metastases from 2000 to 2006 were retrospectively reviewed and compared with the results of preoperative imaging modalities: Ultrasound (US), Computed Tomography (CT), and/or Magnetic Resonance (MR). The number of cases in which IOUS and preoperative imaging studies produced discordant results, in terms of presence/absence of focal liver lesions, was calculated per year. Statistical analysis was performed using the McNemar test. A p value < 0.05 was considered statistically significant.

RESULTS

Eighty-three IOUS scans performed in 2000-2003 were reviewed, and discordance with preoperative imaging findings was found in 19/83 (23%) cases. Of the 42 IOUS scans done during the 2004-2006 period, 10/42 (24%) showed discordance with preoperative studies. All metastases diagnosed with imaging studies were pathologically confirmed. The number of discordant cases in the two periods were not significantly different (p = 0.2).

CONCLUSION

IOUS is still useful in the detection of liver metastases. Its decreased use is probably due to the improved accuracy of preoperative imaging modalities.

Accurate preoperative localization of insulinomas avoids the need for blind resection and reoperation: analysis of a single institution experience with 17 surgically treated tumors over 19 years

INTRODUCTION

Presently, the need for and choice of preoperative localization tests for insulinomas remain controversial. We report the results from a single institution experience whereby the management policy adopted was that of accurate preoperative localization before surgical exploration.

MATERIALS AND METHODS

From 1990 to 2008, 17 patients with a clinical and biochemical diagnosis of an insulinoma who underwent surgery were retrospectively reviewed. The diagnosis of all insulinomas were confirmed pathologically.

RESULTS

All tumors were localized preoperatively and an average of 2.2 preoperative localization studies including 1.4 noninvasive studies and 0.8 invasive studies were utilized per patient. Invasive localization modalities were more sensitive (92%) than noninvasive modalities in localizing insulinomas (71%). Intra-arterial calcium stimulation with hepatic venous sampling was the most sensitive invasive modality (100%), whereas magnetic resonance imaging was the most sensitive noninvasive modality (63%). Fifteen of 17 tumors (88%) were localized intraoperatively via inspection/palpation and/or intraoperative ultrasonography. Both insulinomas which were not localized intraoperatively were localized correctly to the distal pancreas via preoperative transhepatic portal venous sampling. None of the patients required a blind resection or surgical reexploration for failed localization. All 17 patients underwent complete surgical resection which included eight enucleations and nine distal pancreatectomies with a cure rate of 94% (16/17) at a median follow-up of 35 (range, 1-217) months. The postoperative morbidity and long-term outcome of enucleation was similar to distal pancreatectomy despite a higher rate of microscopic margin involvement.

CONCLUSION

Accurate preoperative localization of insulinomas is useful as it eliminates the need for blind distal pancreatectomy and avoids reoperation. Complete surgical resection is the treatment of choice, and whenever possible, a pancreas-sparing approach such as enucleation should be adopted.

Intraoperative ultrasound of the pancreas

Intraoperative ultrasound provides spatial resolution of the pancreas superior to computed tomography, magnetic resonance imaging, and transabdominal sonography. This pictorial essay will review common benign and malignant pancreatic processes including the following: pancreatic ductal adenocarcinoma, pancreatitis, endocrine tumors, mucinous cystic neoplasm, intraductal papillary mucinous neoplasm, serous cystadenoma, and solid pseudopapillary tumor. The use of intraoperative ultrasound in specific surgical situations will be discussed, which include the following: (1) identification of insulinoma(s) which are not detectable preoperatively, (2) identification of the pancreatic duct to determine dissection planes for chronic pancreatitis surgery (eg, Puestow procedure) and for tumor resection, and (3) staging purposes for malignant disease.

Laparoscopic surgery for pancreatic insulinomas: a single-institution experience of 29 cases

BACKGROUND

Laparoscopic approach has been increasingly used in the treatment of pancreatic benign diseases. This report evaluates our experience with laparoscopic surgery for pancreatic insulinomas.

METHODS

Between July 2000 and December 2007, laparoscopic pancreatectomy was attempted in 29 consecutive patients with insulinomas. The localization of tumors, operating characteristics, and clinical outcomes were analyzed.

RESULTS

Tumors were precisely localized in 28 of 29 (96.6%) patients by a combination of preoperative imaging techniques and intraoperative ultrasonography. Laparoscopic pancreatectomy was successfully performed in 26 patients, including enucleation (n = 14), hand-assisted enucleation (n = 2), and distal pancreatectomy with (n = 9) or without (n = 1) spleen preservation. Two conversions to open procedure were required because of unfavorable locations of the tumors. The pancreatic fistula occurred in four patients who underwent tumor enucleation. The median hospital stay was 5.5 days (range, 3-18 days) after laparoscopic procedure. Twenty-eight patients with pancreatic resection were free of symptoms and remained normoglycemic after a median follow-up period of 19 months (range, 10-36 months).

CONCLUSION

Laparoscopic pancreatic resection is a feasible and safe procedure for patients with insulinomas. Further studies are required to evaluate the potential application of the hand-assisted approach for tumors located at anatomically unfavorable positions.

Gastrointestinal neuroendocrine tumors: pancreatic endocrine tumors

Pancreatic endocrine tumors (PETs) have long fascinated clinicians and investigators despite their relative rarity. Their clinical presentation varies depending on whether the tumor is functional or not, and also according to the specific hormonal syndrome produced. Tumors may be sporadic or inherited, but little is known about their molecular pathology, especially the sporadic forms. Chromogranin A appears to be the most useful serum marker for diagnosis, staging, and monitoring. Initially, therapy should be directed at the hormonal syndrome because this has the major initial impact on the patient's health. Most PETs are relatively indolent but ultimately malignant, except for insulinomas, which predominantly are benign. Surgery is the only modality that offers the possibility of cure, although it generally is noncurative in patients with Zollinger-Ellison syndrome or nonfunctional PETs with multiple endocrine neoplasia-type 1. Preoperative staging of disease extent is necessary to determine the likelihood of complete resection although debulking surgery often is believed to be useful in patients with unresectable tumors. Once metastatic, biotherapy is usually the first modality used because it generally is well tolerated. Systemic or regional therapies generally are reserved until symptoms occur or tumor growth is rapid. Recently, a number of newer agents, as well as receptor-directed radiotherapy, are being evaluated for patients with advanced disease. This review addresses a number of recent advances regarding the molecular pathology, diagnosis, localization, and management of PETs including discussion of peptide-receptor radionuclide therapy and other novel antitumor approaches. We conclude with a discussion of future directions and unsettled problems in the field.

Occult sporadic insulinoma: Localization and surgical strategy

Insulinomas continue to pose a diagnostic challenge to physicians, surgeons and radiologists alike. Most are intrapancreatic, benign and solitary. Biochemical diagnosis is obtained and imaging techniques to localize lesions continue to evolve. Surgical resection is the treatment of choice. Despite all efforts, an occult insulinoma (occult insulinoma refers to a biochemically proven tumor with indeterminate anatomical site before operation) may still be encountered. New localization preoperative techniques decreases occult cases and the knowledge of the site of the mass before surgery allows to determine whether enucleation of the tumor or pancreatic resection is likely to be required and whether the tumor is amenable to removal via a laparoscopic approach. In absence of preoperative localization and intraoperative detection of an insulinoma, blind pancreatic resection is not recommended.

Enucleation of pancreatic neoplasms

BACKGROUND

Standard resections for benign and borderline neoplasms of the pancreas are associated with a significant risk of long-term functional impairment, whereas enucleation preserves healthy parenchyma and pancreatic function. The aim of this study was to evaluate postoperative and long-term oncological and functional results after pancreatic enucleation.

METHODS

Data collected prospectively from 61 consecutive patients who underwent pancreatic enucleation were analysed.

RESULTS

There were no deaths. A clinically significant pancreatic fistula was reported in 14 patients (23 per cent), and five patients (8 per cent) had a further operation for fistula-related complications. The most common indication for surgery was endocrine neoplasm (38 patients; 62 per cent) and two patients (3 per cent) had a final histopathological diagnosis of malignant neoplasm. At a median follow-up of 61 months no patient had developed tumour recurrence or exocrine insufficiency. Two elderly patients developed non-insulin-dependent diabetes.

CONCLUSION

Enucleation is an effective procedure for the radical treatment of benign and borderline neoplasms of the pancreas, with good long-term outcomes.

Surgery in malignant pancreatic neuroendocrine tumors

BACKGROUND

Because of their rarity and indolent nature, optimal management of malignant pancreatic neuroendocrine tumors remains controversial. The purpose of this study is to review a series of patients with these tumors and investigate the role of surgery in the treatment.

METHODS

A retrospective study of 73 patients (ages 24-86 years; 36 women) undergoing treatment at a tertiary academic medical center was performed. Patient demographics, diagnostic tests, operations, pathologic findings, adjuvant treatments, and survival were reviewed.

RESULTS

Seventy-four percent of patients had advanced disease with hepatic metastases and 30% had functional tumors. Fifty-seven percent of the patients underwent pancreatic resections. Two 60-day mortalities occurred and the postoperative complication rate was 27%. Overall 5-year survival rate was 44%. There was no difference in survival between patients with functional and nonfunctional tumors. Patients undergoing resection, even in metastatic disease, had better survival than patients who had no resection (60% vs. 30%, P = 0.025). Recurrence occurred in 20% of patients who underwent a curative resection.

CONCLUSION

Patients with malignant pancreatic neuroendocrine tumors commonly present with advanced disease. Although, curative resection is not frequent, survival benefit may be obtainable with aggressive surgical management even in the face of metastatic disease.

The role of intra-arterial calcium stimulation test with hepatic venous sampling (IACS) in the management of occult insulinomas

BACKGROUND

Occult insulinomas remain a clinical challenge. Specifically designed protocols are necessary to aid detection and facilitate a focused pancreatic exploration.

METHODS

Seventeen non-multiple endocrine neoplasia (non-MEN) patients referred to this medical center in the past 10 years because of equivocal diagnosis, failure of previous operation or difficulty in localization for insulinomas were studied. A routine intra-arterial calcium stimulation test with venous sampling (IACS test) was done for lesion localization. An exploratory laparotomy with intraoperative ultrasound (IOUS) examinations was performed.

RESULTS

Preoperative imaging (sonography, high-resolution computed tomography scan, and magnetic resonance imaging) found six insulinomas, and IOUS found an additional six in the pancreatic regions; all were compatibly indicated by the IACS test. The remaining five patients with occult lesions by IOUS were treated by 40% (1) or 60-70% (4) distal pancreatectomies when insulin gradients were demonstrated on calcium stimulation to the splenic or to the superior mesenteric artery, respectively, and nesidioblastosis was found in each pathology examination. There were no complications related to the arterial stimulation and venous sampling (ASVS) test. No patient had recurrent hyperinsulinism, permanent morbidity, or mortality from surgery.

CONCLUSIONS

IACS test helps in the diagnosis of equivocal pancreatogenous hypoglycemia, indicating the pancreatic region of priority exploration and guiding a pancreatic resection.

Imaging of neuroendocrine tumors

Neuroendocrine tumors (NETs) are rare neoplasms, which are characterized by the presence of neuroamine uptake mechanisms and/or peptide receptors at the cell membrane and these features constitute the basis of the clinical use of specific radiolabeled ligands, both for imaging and therapy. Radiolabeled metaiodobenzylguanidine (MIBG) was the first radiopharmaceutical used to specifically depict and localize catecholamine-secreting tumors (pheochromocytomas, paragangliomas, and neuroblastomas) and is still regarded as a first-choice imaging technique for diagnosis and follow-up; in patients with malignant disease, MIBG scintigraphy is an essential step to select patients for (131)I-MIBG therapy. Scintigraphy with (111)In- or (99m)Tc-labeled somatostatin analogs has become the main imaging technique for NETs, particularly those expressing a high density of somatostatin receptors, such as gastroenteropancreatic tumors; this procedure is used routinely for localizing the primary tumor, evaluating disease extension, monitoring the effect of treatment and for selecting patients for radioreceptor therapy. Since the recent development of hybrid machines, it has been possible to obtain images that simultaneously hold both anatomic (computed tomography [CT]) and functional (single-photon emission computed tomography [SPECT] or positron emission tomography [PET]) information, with great impact on diagnostic accuracy. Significant improvements have been made during the past few years with the development of highly specific radiopharmaceuticals for PET studies that reflect the different metabolic pathways of NETs, such as glucose metabolism ((18)F-fluorodeoxyglucose), the uptake of hormone precursors ((11)C-5-hydroxytryptophan, (11)C- or (18)F-dihydroxyphenylalanine, (18)F-fluorodopamine), the expression of receptors ((68)Ga-labeled somatostatin analogs), as well as the synthesis, storage, and release of hormones ((11)C-hydroxyephedrine and others). Among these radiopharmaceuticals, (68)Ga-labeled somatostatin analogs are increasingly used in specialized centers in Europe for PET and PET/CT imaging and show very promising results with high diagnostic sensitivity. New somatostatin analogs with different receptor affinity as well as other peptides are currently under investigation and will further improve our diagnostic and therapeutic capabilities in the future.

Laparoscopic versus open approach for solitary insulinoma

BACKGROUND

In recent years, advances in laparoscopic techniques have allowed surgeons to treat pancreatic lesions laparoscopically. Insulinoma, the most prevalent pancreatic endocrine tumor, is mostly benign and curable with surgical resection. This study aimed to assess the results from laparoscopic resection (LG) of insulinomas and to compare them with the results from open surgery (OG).

METHODS

From September 1999 to December 2005, 56 laparoscopic pancreatic resections were performed for selected patients, including 12 laparoscopic resections of insulinomas. The results were compared with those of patients who underwent open resection of insulinomas selected from the authors' pancreatic database.

RESULTS

Three conversions to the open approach were required because of inability to identify the tumor. There were no deaths in either group, and the morbidity rates were 25% (3/12) for LG and 55% (5/9) for OG (nonsignificant difference). The pancreatic fistula rate after laparoscopic enucleation was statistically lower than after open enucleation (14% vs 100%; p = 0.015). The mean postoperative hospital stay was 13 +/- 5.9 days for LG and 17.6 +/- 7.5 days for OG (nonsignificant difference). After exclusion of the patients who underwent conversion to laparotomy, the mean postoperative hospital stay was 11.5 +/- 5.8 days for LG and 17.6 +/- 7.5 days for OG (p = 0.04).

CONCLUSION

This study demonstrates the feasibility and safety of laparoscopic resection of insulinomas. The laparoscopic approach was associated with a decrease in hospital stay and pancreatic fistula after enucleation. Preoperative localization tests and laparoscopic ultrasonography seem necessary to prevent conversion.

Ultrasonography of the pancreas. 7. Intraoperative imaging

The usefulness of intraoperative ultrasonography (IOUS) has been documented in the Literature since the Eighties and, although its main applications are in hepatobiliary and pancreatic surgery, it has been used also in neurosurgery, cardiovascular and endocrine surgery. The continuous technical developments have led to an increase in the diagnostic accuracy of IOUS from the Eighties to now. The use of IOUS has increased in time together with the technical innovations until, mainly in the midnineties, its value was recognized by many surgeons. This results have been obtained with scanners that allow to depict fine anatomical details and detect small lesions in real time with extremely high spatial resolution. IOUS is able to shows fine details, such as primary or secondary lesions not detectable with other preoperative imaging modalities or tumor extension and its relationship with vessels. Assessment of resectability by IOUS may determine important changes in therapeutic planning. The role of IOUS, however, has recently been down-sized, especially in those centers where preoperative imaging is advanced. This article will review the clinical role of pancreatic IOUS in the different pancreatic pathologies.

The management of insulinoma

BACKGROUND

Insulinomas are rare tumours. Their clinical presentation, localization techniques and operative management were reviewed.

METHODS

An electronic search of the Medline, Embase and Cochrane databases was undertaken for articles published between January 1966 and June 2005 on the history, presentation, clinical evaluation, use of imaging techniques for tumour localization and operative management of insulinoma.

RESULTS AND CONCLUSION

Most insulinomas are intrapancreatic, benign and solitary. Biochemical diagnosis is obtained during a supervised 72-h fast. Non-invasive preoperative imaging techniques to localize lesions continue to evolve. Intraoperative ultrasonography can be combined with other preoperative imaging modalities to improve tumour detection. Surgical resection is the treatment of choice. In the absence of preoperative localization and intraoperative detection of an insulinoma, blind pancreatic resection is not recommended.

Intraoperative ultrasonography in open and laparoscopic abdominal surgery: an overview

This article reviews the current state of intraoperative ultrasonography in open surgery (IOUS) and laparoscopic surgery (LUS). The review is based on extensive study of data published (Pubmed search) and on 25 years of personal experience with intraoperative ultrasonography. The main application areas of IOUS and LUS and its use during liver, biliary tract, and pancreatic surgery are discussed. The benefits and limitations as well as future expectations with regard to the existing and emerging applications also are discussed. New developments in ultrasound technology and the increasing experience of surgeons in ultrasonography secure the future for IOUS and LUS.

Computed tomography, endoscopic, laparoscopic, and intra-operative sonography for assessing resectability of pancreatic cancer

Pancreas cancer is the fourth leading cancer killer in adults. Cure of pancreas cancer is dependent on the complete surgical removal of localized tumor. A complete surgical resection is dependent on accurate preoperative and intra-operative imaging of tumor and its relationship to vital structures. Imaging of pancreatic tumors preoperatively and intra-operatively is achieved by pancreatic protocol computed tomography (CT), endoscopic ultrasound (EUS), laparoscopic ultrasound (LUS), and intra-operative ultrasound (IOUS). Multi-detector CT with three-dimensional (3-D) reconstruction of images is the most useful preoperative modality to assess resectability. It has a sensitivity and specificity of 90 and 99%, respectively. It is not observer dependent. The images predict operative findings. EUS and LUS have sensitivities of 77 and 78%, respectively. They both have a very high specificity. Further, EUS has the ability to biopsy tumor and obtain a definitive tissue diagnosis. IOUS is a very sensitive (93%) method to assess tumor resectability during surgery. It adds little time and no morbidity to the operation. It greatly facilitates the intra-operative decision-making. In reality, each of these methods adds some information to help in determining the extent of tumor and the surgeon's ability to remove it. We rely on pancreatic protocol CT with 3-D reconstruction and either EUS or IOUS depending on the tumor location and operability of the tumor and patient. With these modern imaging modalities, it is now possible to avoid major operations that only determine an inoperable tumor. With proper preoperative selection, surgery is able to remove tumor in the majority of patients.

[Surgical treatment of gastric, enteric, and pancreatic endocrine tumors Part 1. Treatment of primary endocrine tumors]

Endocrine tumors (ET) of the digestive tract (formerly called neuroendocrine tumors) are rare. They are classified into two principal types: gastrointestinal ET's (formerly called carcinoid tumors) which are the most common, and pancreaticoduodenal ET's. Functioning ET's secrete polypeptide hormones which cause characteristic hormonal syndromes. The management of ET is multidisciplinary. Poorly-differentiated ET's have a poor prognosis and are treated by chemotherapy. Surgical excision is the only curative treatment of well-differentiated ET's. The surgical goals are to: 1. prolong survival by resecting the primary tumor and any nodal or hepatic metastases, 2. control the symptoms related to hormonal secretion, 3. prevent or treat local complications. The most common sites of gastrointestinal ET's ( carcinoids) are the appendix and the rectum; these are often small (<1 cm), benign, and discovered fortuitously at the time of appendectomy or colonoscopic removal. Ileal ET's, even if small, are malignant, frequently multiple, and complicated in 30-50% of cases by bowel obstruction, mesenteric invasion, or bleeding. The carcinoid syndrome (consisting of abdominal pain, flushing, diarrhea, hypertension, bronchospasm, and right sided cardiac vegetations) is caused by the hypersecretion of serotonin into the systemic circulation; it occurs in 10% of cases and is usually associated with hepatic metastases. More than half of the cases of pancreatic ET are non-functional. They are usually malignant and of advanced stage at diagnosis presenting as a palpable or obstructing mass or as liver metastases. Insulinoma and gastrinoma (cause of the Zollinger-Ellison syndrome) are the most common functional ET's. 80% are sporadic; in these cases, tumor size, location, and malignant potential determine the type of resection which may vary from a simple enucleation to a formal pancreatectomy. In 10-20% of cases, pancreaticoduodenal ET presents in the setting of multiple endocrine neoplasia (NEM type I), an autosomal-dominant genetic disease with multifocal endocrine involvement of the pituitary, parathyroid, pancreas, and adrenal glands. For insulinoma with NEM-I, enucleation of lesions in the pancreatic head plus a caudal pancreatectomy is the most appropriate procedure. For gastrinoma with NEM-I, the benefit of surgical resection for tumors less than 2-3 cm in size is not clear. The lesions are frequently small, multiple, and widespread and recurrence is frequent after excision. The long-term prognosis is nevertheless fairly good. But the eventual development of liver metastases which are the most common cause of mortality still argues for an aggressive surgical approach in the early stages of the disease.