Nonfunctioning Endocrine Tumors Research Articles

Solid non-functioning endocrine tumors of the pancreas: correlating computed tomography and pathology

BackgroundSince prognosis and treatment of pancreatic endocrine tumors (pNET) are based on tumor grade, contrast-enhanced multidetector computed tomography (MDCT) features of solid non-functioning pNETs were studied and correlated with pathology tumor grading. MethodsMDCTs of diagnosed pNETs were reviewed retrospectively. Each tumor was analyzed for location, size, homogeneity, margins, arterial and venous phase enhancement, main pancreatic duct diameter, calcifications, vascular invasion, lymph-nodes enlargement, and liver metastases. ResultsOf 154 pNETs presenting between January 2000 and May 2016 with available histology from resected specimen or biopsy, there were 65 G1, 72 G2 and 17 G3 pNETs. Tumor diameter varied significantly between the three groups. Tumors >20 mm were more frequently malignant and non-homogeneous than smaller tumors. G1 tumors were more commonly hypervascular and G3 tumors more often non-hypervascular in the arterial phase. Arterial phase non-hyperdensity and tumor non-homogeneity had a higher rate of metastatic lesions. Vascular invasion correlated with presence of metastases and histological grade. G3 tumors were all >20 mm (p = 0.007), more often non-hypervascular in the arterial phase (p = 0.0025), and non-hyperdense in the venous phase (p = 0.009), and showed more often vascular invasion (p = 0.0198). ConclusionCT correlated with tumor grade; differentiating low-grade and high-grade pNETs through routine CT imaging might improve patient management.

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.

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.

Reduced Port Surgery for Laparoscopic Distal Pancreatectomy Using the Transumbilical Approach with Zigzag Incision

Introduction: Laparoscopic surgery in distal pancreatectomy (DP) is as an effective approach for patients with pancreatic disease because of the reduction in the blood loss, length of hospital stay, and risks of overall postoperative complications and wound infection, without a substantial increase in the operating time.1 Moreover, single-port laparoscopic surgery has become increasingly popular with a widened indication in more types of surgery. However, compared with the conventional laparoscopy, this approach may take longer to complete and requires advanced skills and dedicated instrumentations to compensate for the lack of triangulation.2 In particular, the Gelport laparoscopic system provides a flexible, airtight fulcrum to facilitate the triangulation of standard instrumentation while maintaining the pneumoperitoneum for a minimally invasive surgery. As it is easy to perform hand-assisted operation at the same time, the surgeon can cope with unexpected bleeding with safe quickly. The device has been used for various organ laparoscopic surgeries.3–5 The combination of the umbilical zigzag skin incision technique and the Gelport laparoscopic system was introduced as an effective procedure for laparoscopic surgery to various organs, reconciling the reduction of technical difficulties with the cosmetic outcomes in laparoscopic surgery.6 In this video (410 seconds), we demonstrate the technique as a safe procedure for reduced port surgery performed in laparoscopic DP, without adverse cosmetic effects. Materials and Methods: A 64-year-old woman underwent laparoscopic DP for pancreatic nonfunctional endocrine tumor. The procedure is described as follows: After marking the umbilical region for a zigzag skin incision, the skin was incised along the line. Then, a Gelport double-ring wound retractor was inserted through the incision, which enlarged the diameter of the fascial opening to 6 cm. The Gelport was latched to the wound retractor ring, and the pneumoperitoneum was then inflated using CO2. Two additional 5-mm trocars were inserted into the upper middle and lower left hypochondria. If the operation field is not enough for continuing the procedure, the 5-mm flexible retractor is useful for lifting the organ through another 5-mm trocar. The pancreatic body and spleen were resected using the standard procedures. After dissection of the splenic artery and vein, the pancreatic parenchyma was dissected using the stapler technique. The dissected specimen was extracted smoothly through the umbilical incision, without any additional incision and destruction of the spleen. The operating time was 385 minutes, and the blood loss was 20 mL. During the postoperative period, the wound in the umbilical region shrank to the bottom of the umbilicus. Results and Conclusions: We introduced a transumbilical approach using the Gelport system with an umbilical zigzag incision for reduced port surgery in laparoscopic DP. Although this procedure took a longer operating time compared to the conventional method, this patient was still a second case for us after experiences of 15 conventional laparoscopic DP cases in our department. We consider that it is not difficult to shorten the operating time by repeating experience. Thus, we suggest that the creation of an umbilical incision using the zigzag technique allows for an easy and safe laparoscopic surgery for pancreatic diseases. The authors have no conflicts of interest or financial ties to disclose. Runtime of video: 6 mins 50 secs

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.

Middle-preserving pancreatectomy for advanced transverse colon cancer invading the duodenun and non-functioning endocrine tumor in the pancreatic tail.

A 73-year-old female was referred to our hospital with a diagnosis of advanced transverse colon cancer with severe anemia and body weight loss. Preoperative evaluations, including colonoscopy, gastroduodenoscopy, and computed tomography, revealed not only a transverse colon cancer massively invading the duodenum, but also a non-functioning endocrine tumor in the pancreatic tail. We performed middle-preserving pancreatectomy (MPP) with right hemicolectomy for these tumors with a curative intent. After the resection, about 6cm of the body of the pancreas was preserved, and signs of diabetes mellitus have not appeared. The postoperative course was complicated by a grade B pancreatic fistula, but this was successfully treated with conservative management. After a 33-day hospital stay, the patient returned to daily life without signs of pancreatic exocrine insufficiency. Although the long-term follow-up of the patient is indispensable, in this case, MPP might be able to lead to the curative resection of transverse colon cancer massively invading the duodenum and non-functioning endocrine tumor in the pancreatic tail with preservation of pancreatic function.

Imaging of neuroendocrine gastroenteropancreatic tumours

The role of imaging in functioning endocrine tumours (FETs) is primarily to detect the tumour, that is, to verify lesion number and location. Radiological detection of carcinoid tumours is limited by typical tumour location throughout the gastrointestinal tract or appendix and is therefore dependent on the tumour being large enough to make it recognisable in that site. The most common FET is insulinoma, which is commonly characterised by the typical appearance of a hypervascular lesion at multidetector-row computed tomography and magnetic resonance imaging. A particularly important role is played by intraoperative ultrasound in defining the exact number of lesions, their relationship with adjacent vascular structures and the pancreatic duct for the purposes of correct surgical planning (enucleation or resection). In the setting of nonfunctioning endocrine tumours (NFETs), which manifest late as large masses causing compression symptoms or as incidental findings, imaging is not primarily aimed at tumour detection, as this is relatively easy given the large size of the lesions. Rather, its role is to characterise the tumour and, in particular, to differentiate pancreatic NFET from ductal adenocarcinoma, as in comparison, malignant NFETs have a more favourable prognosis (5-year survival rate 40% compared with 3%-5% for adenocarcinoma) and therefore require different treatment approaches. As NFET are often malignant, they also require accurate staging and appropriate follow-up. In 80% of cases, NFETs have a "typical" imaging appearance: location in the pancreatic head, large dimensions (diameter between 5 and 15 cm, >10 cm in 30% of cases), capsule, sharp and regular margins owing to the expansile and noninfiltrative growth pattern, solid density and arterial hypervascularity. Some 20% of NFETs display different imaging characteristics ("atypical" appearance) as a result of arterial hypovascularity due to the presence of abundant fibrous stroma. Lastly, a small percentage of NFETs has yet a different appearance ("unusual") due to the cystic nature and/or diffuse location throughout the pancreatic parenchyma.

膵の小嚢胞性病変として発見された非機能性内分泌腫瘍の1例

症例は49歳女性．人間ドックで施行した腹部超音波検査で，膵頭部に17mmの嚢胞性腫瘤を認め，精査・加療目的で入院となった．腹部造影CTでは膵頭部に辺縁に造影効果を有する低吸収性の腫瘍を認め，MRIで嚢胞性腫瘍と診断した．ERCPで嚢胞と膵管の交通はなく，膵液細胞診はClass IIIであった．経過観察することも選択肢の一つと考えたが，最終的に内分泌腫瘍などの前癌病変を含めた悪性腫瘍の可能性も否定出来ないことを説明し，本人の希望により幽門輪温存膵頭十二指腸切除術を施行した．切除標本では，膵頭上部に厚い線維性被膜に囲まれた血性の内溶液を有する2cm弱の嚢胞性腫瘍を認め，病理診断は非機能性高分化型の内分泌腫瘍であった．2cm未満の比較的小さな無症状の嚢胞性膵腫瘍は経過観察可能な場合もあるが，本症例のごとく，悪性率の高い非機能性膵内分泌腫瘍などの可能性も念頭におき治療方針を決定する必要がある．

Treatment and prognosis of nonfunctional pancreatic endocrine tumor

Imaging techniques of nonfunctional pancreatic endocrine tumors (NFPET) including ultra-sonography, CT, magnetic resonance imaging and endoscopic ultrasonography (EUS). EUS is more sensitive at finding pancreatic head tumor. Surgery is the only treatment modality with the potential of cure. Tumors should be resected if volum is sporadic or more than 2 cm in multiple endocrine neoplasia Ⅰ. The treatment for/iver metastases include liver resection,chemoembolisation and Liver transplantation. Compared with pancreatic canc-er, patients with completely resected tumors have good prognosis. Key words: Multiple endocrine neoplasm type Ⅰ ; Pancreatic neoplasms; Diagnosis; Therapy; Prog-nosis

Endocrine Tumor of the Pancreas

Clinicopathological findings and pancreatograpy of thirteen patients (male: female = 7:6) with nonfunctioning endocrine tumors (ET) of the pancreas were reviewed. Abnormal endoscopic retrograde pancreatography (ERP) findings were observed in eight 22 cases (62%). Tumors with lymphatic invasion, venous invasion and/or splenic vein invasion were defined as malignant ET. Four malignant ET showed abnormal ERP findings, while five ET without any ERP findings were all histologically benign. A relationship between ERP findings and histological malignant potential is suggested. Histological examination revealed that changes of the main pancreatic duct (MPD) could be classified into three patterns; 1) tumor compression of the MPD (n = 3), 2) tumor infiltration into the MPD (n = 2), 3) tumor with fibrous stroma proliferating around the MPD (n = 3). Tumors showing the last histological findings were all immunoreactive to serotonin antibody, therefore these tumors were those of classical enterochromaffin cell carcinoid tumors.

Cervical metastases of glucagonoma in a patient with multiple endocrine neoplasia type 1: Report of a case

Multiple endocrine neoplasia type 1 (MEN 1) is a syndrome characterized by tumors of the parathyroid glands, pancreatic islet cells, duodenum, and pituitary gland. We report a case of cervical metastases of glucagonoma with MEN 1. The patient was a 34-year-old woman admitted to our hospital with epigastric pain. Her medical history included two resections of prolactinoma and two upper GI hemorrhages secondary to duodenal ulcers. Computed tomography (CT) showed two hypervascular lesions in the tail of the pancreas and cervical ultrasound showed multiple hypoechogenic ovoid images in the neck. A cervical CT scan confirmed two 15-mm lymph nodes in the left cervical region and 111In-DOTATOC imaging showed focal abnormal somatostatin expression in the pancreatic tail and the cervical nodes. The patient had asymptomatic hypoglycemic episodes, with blood sugar levels as low as 30 mg/dl, which raised our suspicion of MEN 1 associated with pancreatic insulinoma. Thus, we performed a distal pancreatectomy with bilateral cervical dissection and parathyroid gland resection. Histopathological examination revealed 12 pancreatic tumors as well as metastases in four cervical lymph nodes. The resected parathyroid glands had normal structure, suggesting parathyroid hyperplasia. A follow-up CT scan, 18 months after surgery, showed new tumors in the head of the pancreas and in the duodenal wall. A pancreatoduodenectomy was performed and histopathological examination revealed nine nonfunctioning endocrine tumors in the pancreas, one tumor in the duodenal wall, and metastases in two peripancreatic lymph nodes. The patient recovered well and remains asymptomatic.

非機能性膵内分泌腫瘍の１切除例

We report a rare case of a very large nonfunctioning endocrine tumor of the pancreas without malignant histological features. A 63-year-old woman referred for appetite loss and general fatigue was found to have a tumor in the pancreas head. Computed tomography demonstrated a well-defined pancreatic tumor 45mm in diameter with hypervascular staining in the pancreas head. Angiography showed a hypervascular tumor of the pancreas head and a dilatation of the anterior superior and posterior superior pancreaticoduodenal arteries. The preoperative diagnosis was an endocrine tumor of the pancreas, with undeniable malignancy. Pylorus-preserving pancreaticoduodenectomy was performed. The histopathological diagnosis was a benign nonfunctioning endocrine tumor of the pancreas based on immunohistochemical staining for Chromogranin A, Synaptophysin, and NSE, but not for hormones. The tumor revealed a low labeling index (<2.0%) of Ki-67 indicating its benign character. No tumor recurrence has been identified in the 18 months since surgery.

MULTIPLE NON-FUNCTIONING ENDOCRINE TUMORS OF THE PANCREAS

: The patient was a 51-year-old woman with diabetes mellitus. Abdominal ultrasonography revealed two hypoechoic lesions in the pancreas body and tail. CT showed low density areas without enhancement. Serum hormones (insulin, gastrin, glucagons) were within normal limits. Based on a diagnosis of multiple non-functioning endocrine tumors or solid-pseudopapillary tumors without cystic degeneration, spleen preserving distal pancreatectomy was performed. Histopathologically, neoplastic cells with small nuclei were arranged in a trabecular form with hyaline degeneration. Both Grimelius argyrophil reaction and chromogranin A reaction were positive. The tumors were diagnosed histopathologically as non-functioning endocrine tumors with hyaline degeneration. There was also marked hyaline degeneration of most of the islet cells in the non-tumor region the pancreas.

Surgery on neuroendocrine tumours

Neuroendocrine tumours of the gastrointestinal tract and pancreas present a major challenge to physicians in their recognition and treatment requirements, and surgical treatment of these tumours has become increasingly important for symptom palliation and survival. For some carcinoid tumours the extent of surgery may depend on tumour size. Midgut carcinoid is the most common cause of the carcinoid syndrome, requiring surgery for primary and mesenteric tumours to minimize the risk for abdominal complications but also for removal of liver metastases to palliate hormonal symptoms. Among endocrine pancreatic tumours, insulinoma and gastrinoma often cause severe symptoms of hormone excess despite their inconspicuous size, but they can be successfully removed with improved pre- and intraoperative localization. Other tumours--glucagonoma, VIPoma, and non-functioning endocrine pancreatic tumours--are often large or metastasizing, but generally require surgical debulking to alleviate hormonal symptoms and have favourable survival.

Malignant Nonfunctioning Endocrine Tumors of the Pancreas: Predictive Factors for Survival after Surgical Treatment

There are scant studies that have analyzed the prognostic factors for malignant nonfunctioning endocrine tumors of the pancreas. We identified the predictive factors associated with long-term survival after surgical resection for malignant nonfunctioning endocrine tumors. Among the 25 patients seen at our hospital with a diagnosis of malignant nonfunctioning endocrine tumor, a review was performed on 22 of these patients who were surgically treated at our institution over the last 10 years. The following factors were evaluated for disease-specific mortality: age, gender, tumor location, tumor size, histological differentiation, status of the resection margin, and status of lymph node involvement. Tumor recurrence was noted in 9 cases (40.9%) among the 22 operated patients. Of the 9 recurrent cases, 7 patients (77.8%) had liver metastases. The median follow-up period was 24.8 (range: 3.7-121.4) months. The overall actuarial 1-, 2- and 5-year survival rates were 84.1%, 72.5%, and 52.8%, respectively. The factor shown to have a favorable independent prognostic significance was a negative resection margin (odds ratio = 19.44, 95% confidence interval = 1.22-310.54, P = 0.036). Definitive surgical resection of the primary tumor was a predictor of long-term survival after surgical resection for malignant nonfunctioning endocrine tumor.

Oncocytic non‐functioning endocrine tumor of the pancreas

Herein is presented the case of a malignant non-functioning endocrine tumor of the pancreas with oncocytic features, and a discussion on the high incidence of malignancy in oncocytic endocrine pancreatic tumors. The patient was a 65-year-old woman who showed no paraneoplastic symptoms produced by functioning pancreatic endocrine tumors. The primary tumor was located in the body and tail of the pancreas, and had metastasized to the liver. Tumor cells were arranged in a ribbon-like or trabecular pattern and had an abundant eosinophilic cytoplasm containing numerous mitochondria and neurosecretory granules. The cytoplasm of the tumor cells was intensely stained with an antimitochondrial antigen antibody. Most tumor cells stained positively with Grimelius stain and for chromogranin A. Some tumor cells also stained for synaptophysin. However, the tumor cells negatively stained for hormones such as insulin, glucagon, somatostatin, gastrin, vasoactive intestinal peptide and pancreatic polypeptide, for serotonin, and for pancreatic enzymes such as amylase and trypsin. Analysis of 18 oncocytic pancreatic endocrine tumors, consisting of those reported previously and that in the present case, suggests that the high incidence of malignancy in oncocytic endocrine tumors is associated with the high incidence of non-functioning endocrine tumors among them, most of which are malignant.

Endoscopic Ultrasound–Guided Fine Needle Aspirate Microsatellite Loss Analysis and Pancreatic Endocrine Tumor Outcome

The clinical course of pancreatic endocrine tumor (PET) varies depending on tumor aggressiveness, disease extent, and possibly accumulated molecular alterations. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) results, although accurate in diagnosing PET, correlate poorly with PET outcome. The role of detecting key molecular abnormalities in predicting PET behavior and clinical outcome from EUS-FNA material remains unknown. Patients with confirmed PET who underwent EUS-FNA during a 32-month period were included. Patient demographics and clinical data were recorded and follow-up information was obtained by contacting their physician to evaluate disease progression. Representative tumor cells were microdissected from the FNA material. DNA was harvested and amplified, targeting a panel of 17 polymorphic microsatellite markers on chromosomes 1p, 3p, 5q, 9p, 10q, 11q, 17p, 17q, 21q, and 22q. The polymerase chain reaction products were subjected to fluorescent capillary gel electrophoresis to detect microsatellite loss. The fractional allelic loss (FAL) was calculated. Twenty-five patients were studied. Thirteen were classified histologically as benign PET limited to the pancreas and 12 as malignant PET (invasive or metastatic). The mean FAL in the benign and malignant PET was 0.03 and 0.37 (P<.0001), respectively. In addition, the mean FAL was significantly greater in those with disease progression as compared with patients with stable disease (0.45 vs 0.09 respectively, P<.0001). Microsatellite loss analysis of EUS-FNA material from PET can be performed reliably and an FAL value of more than 0.2 is associated with disease progression. This technique may have value in the preoperative assessment and risk stratification of patients with PET.

Medial pancreatectomy: a report of 10 cases

目的 探讨中段胰腺切除术的临床应用价值.方法回顾性分析1990年1月至2003年10月间10例中段胰腺切除术病人的临床资料,男6例,女4例,平均年龄46.6岁.本组病例中病理诊断胰腺内分泌肿瘤5例,胰腺囊腺瘤4例,慢性胰腺炎伴胰石症1例.2例行中段胰腺切除+胰头空肠、胰体空肠、空肠空肠吻合术,8例行中段胰腺切除+胰体空肠Roux-en-Y吻合术.结果术后均无死亡.术后发生胰瘘2例,经保守治疗2个月和2周后均痊愈.仅1例无功能性胰岛细胞瘤的病人术后出现血糖轻度增高,随访1年血糖无变化.10例病人中8例随访至2004年4月均健在,无复发.结论中段胰腺切除术适用于位于胃十二指肠动脉左侧和近脾静脉与肠系膜下静脉汇合处之间良性或低度恶性的胰腺肿瘤.该术式有利于降低胰腺术后糖尿病的发生和维持胃肠道的功能。

Endocrine pancreatic tumors: factors correlated with survival

Background: The aim of this study was to evaluate the survival rate of patients with endocrine tumors of the pancreas, functioning or non-functioning, associated or not with MEN 1 syndrome.Patients and methods: Eighty-three patients with pancreatic endocrine tumors diagnosed in our department from 1978 to 2003 were studied.Results: The study included 37 men (44.6%) and 46 women (55.4%). The median age of patients at diagnosis was 55 years (range 19–81 years). Fifty-two patients (62.7%) had non-functioning endocrine tumors, 16 (19.3%) had functioning endocrine tumors and 15 (18.1%) had MEN 1 disease with pancreatic involvement. Twenty-seven patients (32.5%) had liver metastases at the time of diagnosis, involvement of the lymph nodes was found in 47 out of 79 patients (59.5%). Forty patients (48.2%) had radical surgery, 20 (24.1%) had palliative surgery and 53 were treated medically. The survival rate was significantly related to the presence of metastases, lymph node involvement, and the type of tumor and treatment.Conclusions: Tumor resection, the absence of liver and lymph node metastases, and the presence of MEN 1 syndrome are related to a better survival rate. Radical surgery continues to have a central role in the therapeutic approach to endocrine tumors of the pancreas.

Whole-Body 11C-5-Hydroxytryptophan Positron Emission Tomography as a Universal Imaging Technique for Neuroendocrine Tumors: Comparison with Somatostatin Receptor Scintigraphy and Computed Tomography

Neuroendocrine tumors (NETs) can be small and situated almost anywhere throughout the body. Our objective was to investigate whether whole-body (WB) positron emission tomography (PET) with (11)C-5-hydroxytryptophan (5-HTP) can be used as a universal imaging technique for NETs and to compare this technique with established imaging methods. Forty-two consecutive patients with evidence of NET and a detected lesion on any conventional imaging (six bronchial, two foregut, 16 midgut, and two thymic carcinoids; one ectopic Cushing's syndrome; four gastrinomas; one insulinoma; six nonfunctioning endocrine pancreatic tumors; one gastric carcinoid, one paraganglioma; and two endocrine-differentiated pancreatic carcinomas) were studied. The WB-(11)C-5-HTP-PET examinations were compared with WB-computed tomography (CT) and somatostatin receptor scintigraphy (SRS). Tumor lesions were imaged with PET in 95% of the patients. In 58% of the patients, PET could detect more lesions than SRS and CT and equal numbers in 34%, whereas in three cases, SRS or CT showed more lesions. In 84% (16 of 19 patients), PET could visualize the primary tumor compared with 47 and 42% for SRS and CT, respectively. The surgically removed PET-positive primary tumor sizes were 6-30 mm. To conclude, this study indicates that WB-(11)C-5-HTP-PET can be used as a universal imaging method for detection of NETs. This study also shows that WB-(11)C-HTP-PET is sensitive in imaging small NET lesions, such as primary tumors, and can in a majority of cases image significantly more tumor lesions than SRS and CT.