Nonfunctioning Pancreatic Endocrine Tumors Research Articles

Gastrinomas and non-functioning pancreatic endocrine tumors in multiple endocrine neoplasia syndrome type-1 (MEN-1).

Gastrinomas and non-functioning pancreatic endocrine tumors in multiple endocrine neoplasia syndrome type-1 (MEN-1).

The Pancreatic Endocrine Tumors - Experience of First Surgical Clinic Iasi.

Pancreatic neuroendocrine tumors (PNETs) are rare and characterized by widely variable clinical presentation and often challenging surgical management. Methods: Retrospective study conducted during the last 15 years at the First Surgical Clinic of the Iasi St Spiridon University Hospital, and which included all the patients diagnosed with pancreatic endocrine tumors by immunohistochemistry. Results: There were 26 cases diagnosed with PNET. The male/female ratios was 7/19 and mean age 41.93 +- 2.48 years (range 20-79 years). Of the PNET cases 13 were insulinomas, 5 gastrinomas, 2 gastrinomas associated with other endocrine neoplasms (Wermer syndrome), 5 non-functional endocrine pancreatic tumors and 1 ACTHoma. Clinical manifestations depended on tumor type: hypoglycemia and Whipple triad for insulinoma, Zollinger Ellison syndrome and complicated peptic ulcer (hemorrhage, perforation) for gastrinoma, Cushing syndrome for ACTHoma. Biological diagnosis included biological markers (e.g. insulin, gastrin and cortisol). Tumor site and size at diagnosis were determined by ultrasound, CT-scan, angiography, PETscan, octreoscan and intraoperative ultrasound. Surgical procedures for PNET insulinomas were: tumor resection - 6 cases; left splenopancreatectomy - 3 cases; left spleen-preserving pancreatectomy - 2 cases; pancreaticoduodenectomy - 2 cases. We also present 4 cases of gastrinoma with multiple ulcers and multiple surgical interventions for hemorrhage and perforation with peritonitis. The two patients with Wermer syndrome also had ulcers complicated with hemorrhage and peritonitis and parathyroid adenoma. Nonfunctional pancreatic endocrine tumors were diagnosed in 5 women of which in 3 the tumors were located in the pancreatic tail (in which splenopancreatectomy and left pancreatectomy with spleen preservation were performed) and in 2 in the pancreatic head (in which pancreaticoduodenectomy and Beger type operation were performed). Conclusions: Knowledge of clinical signs of secreting tumors and exploring the patients are of crucial importance for management of PNETs. Immunohistochemistry is mandatory for confirming the diagnosis and assessing the proliferation and biological behavior of the tumor, thus facilitating the administration of specific therapy. Aggressive surgical treatment is indicated, even in advanced stages.

Pancreatic involvement in 11 cases of Von Hippel-Lindau disease.

Von Hippel-Lindau disease is an autosomal dominant genetic disorder characterized by neoplasms developing in multiple organs. Although the pancreas is one of the most frequently involved organs, the frequency of pancreatic cysts, cystadenomas, neuroendocrine tumors and diabetes has not been sufficiently evaluated due to the low prevalence of this disease. In this paper, we review and retrospectively analyze 11 patients with von Hippel-Lindau disease. Eleven patients (6 males, 5 females) who underwent CT or MRI scans at Okayama University Hospital between 2002 and 2009 were enrolled in this study. Their pancreatic CT scans, MRI scans, biochemical test results and clinical histories were retrospectively reviewed. All patients had one or more pancreatic involvements. Nine of the 11 patients had multiple pancreatic cysts, 2 had dilatation of the main pancreatic duct, 3 had a non-functioning pancreatic endocrine tumor (one patient required pancreatoduodenectomy due to the endocrine carcinoma) and 3 had diabetes mellitus. Pancreatic cystadenomas were not detected in this case series. The prevalence of pancreatic involvement was 100% in this study. Regular screening and scheduled follow-up for pancreatic lesions and diabetes should be performed on individuals predisposed to von Hippel-Lindau disease.

Long lasting octreotide LAR therapy in non functioning pancreatic neuroendocrine carcinoma

Non functioning endocrine pancreatic tumors (NF-PETs) have absent or low hormone secretion without symptoms and constitue ~60% of PETs. At diagnosis more than 50% of patients have liver metastases and almost 40% are not candidates for radical surgery because of either locally advanced disease or unresectable metastases. We described the case of a 47-year-old woman with a pancreatic carcinoma with secondarism in the liver not suitable for radical surgery. Histological test of liver metastases showed positivity for endocrine well-differentiated non functioning carcinoma expressing receptors for somatostatin with very low proliferation index (Ki67 < 2%). After this diagnosis she started a specific treatment with octreotide analogues which achieved durable stabilization of the disease.

DNA methylation profiles distinguish different subtypes of gastroenteropancreatic neuroendocrine tumors.

Most studies have considered gastroenteropancreatic neuroendocrine tumors (GEP-NETs) as a homogenous group of samples or distinguish only gastrointestinal from pancreatic endocrine tumors. This article investigates if DNA methylation patterns could distinguish subtypes of GEP-NETs. The DNA methylation level of 807 cancer-related genes was investigated in insulinomas, gastrinomas, non-functioning pancreatic endocrine tumors and small intestine endocrine tumors. DNA methylation patterns were found to be tumor type specific for each of the pancreatic tumor subtypes and identified two distinct methylation-based groups in small intestine endocrine tumors. Differences of DNA methylation levels were validated by pyrosequencing for 20 candidate genes and correlated with differences at the transcriptional level for four candidate genes. The heterogeneity of DNA methylation patterns in the different subtypes of gastroenteropancreatic neuroendocrine tumors suggests different underlying pathways and, therefore, these tumors should be considered as distinct entities in molecular and clinical studies.

Surgical treatment of non–functioning pancreatic tumor

Pancreatic neuroendocrine tumors have a rare annual incidence in the general population and they are classified into functional and non-functional tumors. Non-functioning tumors represent the majority. We report an uncommon non-functional neoplasm that developed into the pancreatic isthmus. A 70-year-old woman presented at the hospital with abdominal pain, nausea and vomiting. The abdominal echography revealed a hypoechoic mass of 65/54 mm with dilatation of the upstream Wirsung duct. Non-contrast-enhanced computed tomographic demonstrated a well-enhanced mass of 4/5/6.5 cm on the head of the pancreas. An endocrine tumor of the pancreas was considered as a preoprerative diagnosis and pancreatectomy was performed with pancreato-jejunum anastomosis- the Beger surgery. As a result, a non-functional endocrine tumor of the pancreas was confirmed anatomo-pathologically. The clinical manifestation of non-functioning endocrine pancreatic tumors is characterized by nonspecific symptoms. They represent a group of neoplasms which can delay the real diagnosis. Currently, CT scans are most used for detection. A rare case of non-functional neuroendocrine pancreatic neoplasm with extensive growth within the head and isthmus part of the pancreas was presented. An early detection of non-functioning endocrine neoplasm of the pancreas is very important and curative resection should be tried for a good prognosis.

Primary pancreatic paraganglioma: A report of two cases and literature review

Paraganglioma is a rare tumor of paraganglia, derived from neural crest cells in sympathetic or parasympathetic ganglions. Primary paraganglioma originating from the pancreas is rare. We report two patients with paraganglioma in the head of the pancreas, in whom computed tomography showed a sharply marginated, hypervascular tumor with cystic areas. Significant intratumoral vessels and early contrast filling of the draining veins from the mass were not found. Although the pancreatic paraganglioma was located at the pancreatic head, the bile ducts often revealed no dilation, and sometimes the main pancreatic duct was mildly dilated. These findings are helpful in differentiating pancreatic paraganglioma from other pancreatic neoplasms. It is often difficult to distinguish between nonfunctional pancreatic paragangliomas and pancreatic endocrine tumors. In many reports,pancreatic paragangliomas show the retroperitoneal extension of a paraganglioma into the pancreas rather than a true pancreatic neoplasm. In surgical treatment, we could select simple excision of the tumor rather than radical surgery.

Efficacy and Cost-Effectiveness of Immediate Surgery versus a Wait-and-See Strategy for Sporadic Nonfunctioning T1 Pancreatic Endocrine Neoplasms

Background: Whether patients with small (<2 cm), sporadic nonfunctioning pancreatic endocrine tumors (NF-PETs) should directly undergo pancreatic surgery or should be followed longitudinally to detect growth and malignancy still has to be defined. Study Design: Based on the pertinent literature of the past decade, a Markov model was developed to investigate this issue. In the wait-and-see strategy arm, surgery was performed if the tumor attained a size ≥2 cm or surpassed 20% of the initial size. In a Monte Carlo probabilistic analysis, 100 hypothetical patients undergoing a wait-and-see strategy were compared to 100 patients directly undergoing surgery, with the aim of investigating the efficacy and cost-effectiveness of the two strategies. Results: During the postdiagnostic lifetime, 63 NF-PETs in the wait-and-see group showed significant growth and underwent surgery: 38 were stage I, 10 were stage II, 15 were stage III and none were stage IV. In the base-case scenario, the mean life expectancy and quality-adjusted life expectancy were found to be superior after immediate surgery [26.1 years and 11.8 quality-adjusted life years (QALYs)] than with the wait-and-see strategy (22.1 years and 8.3 QALYs) as the consequence of ageing during the wait-and-see follow-up which increased mortality due to surgery, when surgery was needed. The model was sensitive to starting age and length of follow-up; in particular, for patients >65 years of age, the two strategies provided similar results but the wait-and-see strategy was more cost-effective. Conclusions: The wait-and-see strategy for NF-PETs <2 cm represents a reasonable approach in patients over 65 years of age; otherwise, immediate surgery is preferable.

18F-FDG PET/CT can be used to detect non-functioning pancreatic neuroendocrine tumors

18F-Fluorodeoxyglucose positron emission tomo-graphy and computed tomography (18F-FDG PET/CT) has limited value in well-differentiated neuroendocrine tumors. The value of 18F-FDG PET/CT in non-functioning pancreatic neuroendocrine tumors, which are often poorly differentiated, malignant, and present at an advanced stage, was also thought to be limited. This study was performed to evaluate the clinical value of 18F-FDG PET/CT in assessing non-functioning pancreatic neuroendocrine tumors. From January2010 to February 2014, a comparable large cohort of patients (31cases) with non-functioning pancreatic neuroendocrine tumors from Shanghai Cancer Center underwent 18F-FDG PET/CT scans. Demographics and clinical characteristics were retrospectively collected and analyzed for all the patients. Twenty-eight of31(90.3%) patients with non-functioning endocrine pancreatic tumors had an elevated 18F-FDG uptake (SUVmax≥2.5). In addition, 18F-FDG PET/CT visualized 38of 42(90.5%) distant metastatic lesions. The 18F-FDG uptake had significant association with tumor size (P=0.012) and TNM stage (P=0.004). The application of 18F-FDG PET/CT has changed the management of 8 cases (8/31, 25.8%). In conclusion, 18F‑FDG PET/CT plays an important role in detecting and staging non-functioning pancreatic neuroendocrine tumors.

Incidental Diagnosis as Prognostic Factor in Different Tumor-Stages of Non-Functioning Pancreatic Endocrine Tumors

BackgroundIncidentally discovered non-functioning pancreatic endocrine tumors (NF-pNETs) are increasingly detected and their management is debated. Moreover, the prognostic significance of incidental diagnosis for locally advanced or metastatic NF-pNETs is unknown. Aim of this study is to analyze the outcomes of incidentally discovered/symptomatic NF-pNETs stratified by tumor stage. A preliminary experience with nonoperative treatment of incidental NF-pNETs is reported. MethodsConsecutive patients with symptomatic/incidental NF-PETs observed between 1990 and 2009 were analyzed considering different tumor stages. Nonoperative management of incidental NF-pNETs was evaluated. ResultsAmong 355 patients with NF-pNETs, the diagnosis was incidental in 124 (35%). Incidental NF-pNETs were more commonly associated with lower tumor-stages compared to symptomatic tumors (P<0.0001), but 30% of incidental NF-pNETs were stage III-IV. Incidental NF-pNETs had higher rates of radical resections and of R0 margins (P<0.0001). 5-year PFS was 83% and 32% for incidental and symptomatic NF-pNETs, respectively (P<0.0001). 5-year PFS was better for incidental NF-pNETs compared to symptomatic tumors for each tumor stage, including stage III (69% versus 27%, P<0.0001) and stage IV (60% versus 17%, P=0.112). After a median follow-up of 36 months there was no tumor progression in 12 patients who underwent nonoperative management of incidental NF-pNETs. Conclusion30% of incidental NF-pNETs present with stage III-IV disease. PFS is much higher for incidental NF-pNETs compared to symptomatic patients and this difference is evident also for stage III-IV tumors, suggesting that absence of symptoms may indicate a less aggressive disease. Nonoperative management can be an alternative to surgery in selected incidental NF-pNETs.

Preoperative assessment of nonfunctioning pancreatic endocrine tumours: role of MDCT and MRI

This study was done to compare the diagnostic accuracy of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the preoperative assessment of nonfunctioning pancreatic endocrine tumours (NFPET). Fifty-one patients (25 men, 26 women; mean age, 52 years), preoperatively investigated by both MDCT and MRI and subsequently operated on with a histological diagnosis of NFPET, were included in this study. MDCT and MRI accuracy in evaluating location, size, margins, baseline density/signal intensity, structure, pattern of enhancement, peak enhancement phase, involvement of main pancreatic duct, involvement of adjacent organs, infiltration of peritumoural vessels, involvement of locoregional lymph nodes, and liver metastases was compared using Pearson correlation, Mann-Whitney and chi-square tests. A value of p<0.05 was considered statistically significant. MDCT and MRI had similar accuracy in assessing size, margins, baseline density/signal intensity, structure, pattern of enhancement, peak enhancement phase, involvement of main pancreatic duct, involvement of adjacent organs, involvement of locoregional lymph nodes, and liver metastases (p>0.05). MDCT was superior to MRI in evaluating the infiltration of peritumoural vessels (p=0.025). MDCT performed better than MRI in assessing vascular involvement and should be considered the best imaging tool for preoperative evaluation of NFPET.

PGP 9.5 immunocytochemical staining for pancreatic endocrine tumors

Aims/hypothesis: Protein gene product 9.5 (PGP 9.5) is a marker for neuroendocrine cells but has not been used for pancreatic islet cells and pancreatic endocrine tumors (PETs). Antibodies for PGP 9.5 are now commercially available for immunocytochemical study, with which immunostaining may be able to differentiate between benign and malignant PETs.Results: All 4 kinds of normal islet cells were positively immunostained for PGP 9.5—moderately positive for β-cells and strongly positive for δ-cells, whereas ganglion cells were immunostained more strongly than islet cells. Nine of 12 insulinomas were moderately to strongly positive for PGP 9.5. Two glucagonomas, 3 of 6 pancreatic polypeptidomas (PPomas), 3 of 9 gastrinomas, and 2 of 4 non-functioning PETs were negative for PGP 9.5.Materials and Methods: Thirty-four PETs were immunocytochemically stained for PGP 9.5 using a rabbit polyclonal antibody together with immunostaining for 4 pancreatic hormones, chromogranin A (CgA), and gastrin. PETs consisted of 12 insulinomas, 2 glucagonomas, 1 somatostatinoma (SRIFoma), 6 PPomas, 9 gastrinomas, and 4 non-functioning PETs.Conclusion/Interpretation: PGP 9.5 immunostaining was universally positive for 4 kinds of islet cells and was moderately to strongly positive for 9 of 12 (75%) insulinomas. All 22 non-β-cell PETs were negative or weakly positive for PGP 9.5, and thus negative or weakly positive PGP 9.5 immunostaining may be used as a marker for potential malignancy and poor prognosis for non-β-cell PETs.

A case of nonfunctioning pancreatic islet cell tumor in a young female

Pancreatic endocrine tumors are uncommon and represent 1-2% of all pancreatic neoplasms. Nonfunctioning pancreatic endocrine tumors constitute 30-40% of pancreatic endocrine tumors. They can occur at any age, but are rare in childhood. About 65-80% of nonfunctioning pancreatic endocrine tumors are associated with clear-cut evidence of malignant behavior. A 14-year-old girl presented with abdominal pain of 2 weeks duration with occasional vomiting. Abdominal examination did not reveal any abnormality. Ultrasound and computed tomography (CT) scan of the abdomen showed solid mass lesion located in the head of pancreas. The patient underwent Whipple's pancreaticodudenectomy. Microscopically, the mass was circumscribed, containing oval to polygonal cells. There was no pleomorphism, significant mitotic activity or evidence of capsular or vascular invasion, and a diagnosis of benign pancreatic islet cell tumor was made. Although benign nonfunctioning pancreatic islet cell tumor is rare in children, such diagnosis should be considered when there is an isolated mass in the pancreas. Appropriate resection of such mass is attended with good outcome.

Metastatic Insulinoma Following Resection of Nonsecreting Pancreatic Islet Cell Tumor: A Case Report and Review of the Literature.

A 56-year-old woman presented to our clinic for recurrent hypoglycemia after undergoing resection of an incidentally discovered nonfunctional pancreatic endocrine tumor 6 years ago. She underwent a distal pancreatectomy and splenectomy, after which she developed diabetes and was placed on an insulin pump. Pathology showed a pancreatic endocrine neoplasm with negative islet hormone immunostains. Two years later, computed tomography scan of the abdomen showed multiple liver lesions. Biopsy of a liver lesion showed a well-differentiated neuroendocrine neoplasm, consistent with pancreatic origin. Six years later, she presented to clinic with 1.5 years of recurrent hypoglycemia. Laboratory results showed elevated proinsulin, insulin levels, and c-peptide levels during a hypoglycemic episode. Computed tomography scan of the abdomen redemonstrated multiple liver lesions. Repeated transarterial catheter chemoembolization and microwave thermal ablation controlled hypoglycemia. The unusual features of interest of this case include the transformation of nonfunctioning pancreatic endocrine tumor to a metastatic insulinoma and the occurrence of atrial flutter after octreotide for treatment.

Ki-67 grading of nonfunctioning pancreatic neuroendocrine tumors on histologic samples obtained by EUS-guided fine-needle tissue acquisition: a prospective study

Preoperative determination of Ki-67 expression, an important prognostic factor for grading nonfunctioning pancreatic endocrine tumors (NF-PETs), remains an important clinical challenge. To prospectively evaluate the feasibility, yield, and clinical impact of EUS-guided fine-needle tissue acquisition (EUS-FNTA) with a large-gauge needle to obtain tissue samples for histologic diagnosis and Ki-67 analysis in patients with suspected NF-PETs. Prospective cohort study. Tertiary-care academic medical center. Consecutive patients with a single pancreatic lesion suspicious for NF-PET on imaging. EUS-FNTA with a 19-gauge needle. Feasibility and yield of EUS-FNTA for diagnosis and Ki-67 expression determination. Thirty patients (mean [± SD] age 55.7 ± 14.9 years), with a mean (± SD) lesion size of 16.9 ± 6.1 mm were enrolled. EUS-FNTA was successfully performed without complications in all patients, with a mean (± SD) of 2.7 ± 0.5 passes per patient. Adequate samples for histologic examination were obtained in 28 of the 30 patients (93.3%). Ki-67 determination could be performed in 26 of these 28 patients (92.9%, 86.6% overall), 12 of whom underwent surgical resection. Preoperative and postoperative Ki-67 proliferation indexes were concordant in 10 patients (83.3%), whereas 2 patients were upstaged from G1 to G2 or downstaged from G2 to G1, respectively. Single center study with a single operator. In patients with suspected nonfunctioning low-grade to intermediate-grade pancreatic neuroendocrine tumors (p-NETs), retrieval of tissue specimens with EUS-FNTA by using a 19-gauge needle is safe, feasible, and highly accurate for both diagnosis and Ki-67 determination. A Ki-67 proliferative index acquired through this technique might be of great help for further therapeutic decisions.

Feasibility of Mesenteric Vein Reconstruction with PTFE Prosthesis for Non Functioning Endocrine Pancreatic Tumor Surgery

Endocrine pancreatic tumors (EPTs) are rare entities with a low incidence (3-10 per million). A relatively frequent feature (15-53%) among this group of tumors is represented by the non-functioning endocrine pancreatic tumors (NFEPTs) whose peculiarity is due to the absent secrection of mature or active hormones, leaving the patient free from clinically evident hypersecrection syndromes, generally discovered when the mass effect becomes evident, the adjacent pancreatic structures (splenic, superior mesenteric and portal vein, celiac or superior mesenteric arteries, common bile duct, duodenum, etc.) are infiltrated or hepatic metastases are growing. A potentially malignant attitude is high and well related to the dimension of the tumor with inexorably fatal outcome if appropriate surgery is delayed. The size of the mass and an evident involvement of nearer vascular structures might rise some doubts about the decision to radically remove the tumor. An aggressive surgery should be balanced with the risk/benefit ratio for generally young patients with a reasonable long life expectancy. We parallel two clinical cases among the patients we observed through the years at our institution and operated on by the same surgeon, who were displaying the same tumoral histology and loco-regional invasiveness of portomesenteric axis, but differing one each other for the presence of metastatic disease to the liver the first case. Further aim of the present report is to support the evidence of the feasibility and safeness of extensive surgical demolition with prosthetic reconstruction of the porto-mesenteric axis.

膵頭部のカルシトニン産生膵内分泌腫瘍核出術後10年目に同部位に多発発生した非機能性内分泌腫瘍の1例

症例は52歳，女性．10年前，膵頭部に認めた4cmのカルシトニン産生膵神経内分泌腫瘍に対して核出術を施行した．術前の血清カルシトニンは438pg/mlと高値であり，組織学的にもカルシトニン染色陽性であった．術後，血清カルシトニンは速やかに20pg/mlまで低下した．初回手術後10年目の造影CT検査で，前回と同じ膵頭部に1～4cmの4個の腫瘍を認めた．多発性の膵神経内分泌腫瘍と診断し，幽門輪温存膵頭十二指腸切除術を施行した．病理組織学的に，腫瘍細胞はクロモグラニンAなどの内分泌マーカー陽性であったが，初回陽性であったカルシトニンは今回陰性であり，非機能性のNET G2（WHO分類）と診断した．カルシトニン産生膵神経内分泌腫瘍の報告は非常に稀であり，また，10年後に同部位に多発した非機能性内分泌腫瘍が，初回腫瘍の局所再発か新たに発生した腫瘍かを考察する上でも非常に興味深い症例と考えられた．

Immunocytochemical staining for islet amyloid polypeptide in pancreatic endocrine tumors

Aims/hypothesis: Islet amyloid polypeptide is originally identified as the chief constituent of amyloid in insulinomas and type 2 diabetic islets. This study aimed to identify islet amyloid polypeptide by immunocytochemical staining in pancreatic endocrine tumors including 30 cases of insulinomas and non-β-cell pancreatic endocrine tumors. Results: In normal islets, 62% of islet cells and 52% of insulin cells were granularly positive for insulin and IAPP, respectively, with more insulin positive cells than IAPP positive cells and some densely positive staining for insulin and IAPP in irregularly shaped a nuclear, degenerating islet β-cells. In pancreatic endocrine tumors, all 10 insulinomas were positive for islet amyloid polypeptide but 2 glucogonomas, 1 somatostatinoma, 6 of 7 pancreatic polypeptidomas, all 7 gastrinomas and all 3 non-functioning pancreatic endocrine tumors were negative for islet amyloid polypeptide whereas one pancreatic polypeptidoma was positive for islet amyloid polypeptide. Methods: Using commercially available rabbit anti-islet amyloid polypeptide antibody, immunocytochemical staining was performed on 30 cases of pancreatic endocrine tumors, consisting of 10 insulinomas, 2 glucagonomas, 1 somatostatinoma, 7 pancreatic polypeptidomas, 7 gastrinomas and 3 non-functioning pancreatic endocrine tumors. Pancreatic tissues containing pancreatic endocrine tumors were systematically immunostained for insulin, glucagon, somatostatin, pancreatic polypeptide, gastrin and chromogranin A, in addition to islet amyloid polypeptide. When normal pancreatic tissues adjacent to pancreatic endocrine tumors were present, insulin, glucagon, somatostatin and islet amyloid polypeptide positive cells were counted for a total of 20 islets, which were divided into large islets and medium islets for each case. Conclusions/Interpretations: All 10 insulinomas and 1 pancreatic polypeptidoma were granularly positive for islet amyloid polypeptide, suggesting all 10 insulinomas contained enough insulin granules for IAPP whereas only one non-β-cell pancreatic endocrine tumor was co-localized with islet amyloid polypeptide in their secretary granules.

Curative resection of a huge malignant pancreatic endocrine tumor by pancreatoduodenectomy with portal and superior mesenteric vein resection and reconstruction using the right ovarian vein: Report of a case

Nonfunctioning pancreatic endocrine tumors (PETs) are rare and generally asymptomatic. A 68-year-old woman who had refused treatment for a pancreatic mass, revealed by ultrasonography to be 55 mm in diameter, was referred to us again 29 months later with jaundice. Investigations showed an 82-mm tumor in the head of pancreas, exposed from the papilla of Vater to the duodenal lumen. After biliary decompression and drainage, we performed pancreatoduodenectomy with resection of the portal vein and superior mesenteric vein, followed by reconstruction using a cylindrically customized autologous graft harvested from the right ovarian vein. The tumor was resected curatively. Microscopically, it consisted of trabecular and ribbon-like arrangement of neoplastic cells. Immunohistochemical staining was positive for chromogranin A and synaptophysin and negative for insulin, gastrin, glucagons, somatostatin, and pancreatic peptide. Although metastasis was detected in a lymph node along the superior mesenteric vein with perineural invasion, the portal and superior mesenteric veins had not been invaded. The diagnosis was well-differentiated nonfunctioning PET. The patient had an uneventful postoperative course, and there has been no evidence of recurrence in 12 months.

Tumor size correlates with malignancy in nonfunctioning pancreatic endocrine tumor

Tumor size is a criterion of staging in nonfunctioning pancreatic endocrine tumors as well as a predictor of outcome after curative resection. This study analyzes the correlation between tumor size and malignancy in patients with nonfunctioning pancreatic endocrine tumors. All patients with nonfunctioning pancreatic endocrine tumors who underwent curative resection (R0) at our institution between 1990 and 2008 were considered. Their clinicopathologic characteristics were compared among 3 different groups according to tumor size. Univariate and multivariable analyses were performed. Over the study period, 177 patients were identified. Overall, 90 patients (51%) had a tumor size ≤2 cm (group 1), 46 (26%) had tumor size between >2 cm and ≤4 cm (group 2), and 41 (23%) had tumor size >4 cm (group 3). Tumors ≤2 cm were more frequently incidentally discovered (group 1, 57% vs group 2, 51% vs group 3, 32%; P = .014) and benign (group 1, 81% vs group 2, 65% vs group 3, 5%; P < .0001). The presence of a nonfunctioning pancreatic endocrine tumor >2 cm and a nonincidental diagnosis of the tumor were independent predictors of malignancy at multivariable analysis. None of the 51 patients (29%) with a pancreatic endocrine tumor ≤2 cm that was incidentally diagnosed died of disease. A strict correlation between tumor size and malignancy in nonfunctioning pancreatic endocrine tumors was demonstrated. A nonoperative management could be advocated for tumors ≤2 cm when discovered incidentally.