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Abstract: We report the case of a 25-year-old man who was undergoing follow-up for neurofibromatosis type 1. The man underwent 68 Ga-DOTATOC PET/CT for a suspected well-differentiated duodenal neuroendocrine tumor. This examination did not reveal any significant uptake, whereas complementary 18 F-FDG PET/CT showed moderate 18 F-FDG uptake in the primary tumor as well as the adenopathy. Histology, a well-differentiated duodenal neuroendocrine tumor was confirmed, consistent with the diagnosis of somatostatinoma. Although rare, this well-differentiated neuroendocrine tumor should be kept in mind as a possible source of false-negative somatostatin receptor PET/CT findings., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Introduction: Pancreatic Neuroendocrine Tumours (p-NETs) are an important disease entity and comprise of peptide-secreting tumours often with a functional syndrome. Accounting for a small percentage of all pancreatic tumours, they have a good overall survival rate when diagnosed early, with surgery being curative. The role of nuclear medicine in the diagnosis and treatment of these tumours is evident. However, the vast majority of patients will require extensive imaging in the form of conventional radiological techniques. It is important for clinicians to have a fundamental understanding of the p-NET appearances to aid prompt identification and to help direct management through neoplastic staging., Methods: This article will review the advantages and disadvantages of conventional radiological techniques in the context of p-NETs and highlight features that these tumours exhibit., Conclusion: Pancreatic neuroendocrine tumours are a unique collection of neoplasms that have markedly disparate clinical features but similar imaging characteristics. Most p-NETs are small and welldefined with homogenous enhancement following contrast administration, although larger and less welldifferentiated tumours can demonstrate areas of necrosis and cystic architecture with heterogeneous enhancement characteristics. Prognosis is generally favourable for these tumours with various treatment options available. However, conventional radiological techniques will remain the foundation for the initial diagnosis and staging of these tumours, and a grasp of these modalities is extremely important for physicians., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Neurofibromatosis type 1 (NF1, von Recklinghausen disease) is inherited in autosomal dominant way genetic disorder, with an incidence at birth 1:3000. It is one of the most common congenital disorders. It is characterized by café-au-lait spots, neurofibromas, and less common MPTST and gliomas of the optic nerve. It is caused by germline mutations of the NF1 gene, which acts as tumor suppressor. Inactivation of the gene leads to increased activation of the kinase pathways, and in consequence, uncontrolled proliferation of cells. The disease predisposes to the development of both benign and malignant tumors. Malignant tumors, but not related to the nervous system occur in neurofibromatosis quite rare. The aim of the study is a literature review of NF1, with presentation of a patient with NF1 and coexisting numerous tumors: synchronous somatostatinoma and gastrointestinal stromal tumor with metachronous prostate adenocarcinoma and non-small cell lung carcinoma. And attempt to answer the question if there is a common pathway for oncogenesis of these four tumors.

Background/objective: Neuroendocrine neoplasms of the pancreas and duodenum with predominant or exclusive immunoreactivity for somatostatin (pdSOMs) are rare, and knowledge about tumour biology, treatment, survival and prognostic factors is limited. This study aims to describe clinical, pathological and biochemical features as well as treatment and prognosis of pdSOMs., Design: Twenty-three patients with pdSOM (9 duodenal, 12 pancreatic and 2 unknown primary tumours) were identified from our prospective neuroendocrine tumour database, and data according to the study aims were recorded., Results: Among the 9 patients with duodenal SOM, the male/female ratio was 4/5. All males and 1 female had neurofibromatosis type 1. Seven patients had stage 1A/B and 2 had stage 2B disease. The Ki-67 index was 1-5% (median 2%). Plasma somatostatin was elevated in the patients with 2B disease. Of the 14 patients with pancreatic SOM or an unknown primary tumour, the male/female ratio was 2/12. One male had multiple endocrine neoplasia type 1. Five had stage 1A/2B and 9 had stage 4. The Ki-67 index was 1-40% (median 7%). Plasma somatostatin was elevated in 7 patients. Patients reported symptoms related to the somatostatinoma syndrome, but none fulfilled the criteria for a full syndrome. Primary tumour in the pancreas, metastatic disease at diagnosis and higher tumour grade were all associated with significantly poorer survival., Conclusion: None of the patients with pdSOM presented with the full somatostatinoma syndrome. Prognostic factors are localisation of the primary tumour, dissemination and tumour grade. A Ki-67 index of 5% may discriminate the course of the disease., (© 2015 S. Karger AG, Basel.)

Objective: Benign lesions of the major papilla are rare but raise the problem of their medical care. We studied the efficacy, safety, and histology of the endoscopic ampullectomy., Patients and Methods: Forty-two endoscopic resections of the major papilla were undertaken in 23 males and 19 females of a mean age of 63. Five patients (12%) presented with a familial adenomatous polyposis. The assessment of resectability included preoperative histology, and endoscopic ultrasound (EUS) in 26 patients (62%) always showing intra-mucosal lesion. The resection was performed with a duodenoscope, using a diathermic loop with a pure current section., Results: The resection was realized in one piece for 34 patients, in 2-4 fragments for 8 patients. A plastic pancreatic stent was inserted in 26 patients (62%), a plastic biliary stent in 10 patients (24%). There were no deaths but nine complications (21%): six acute pancreatitis (four patients with a pancreatic stent, contrary to the literature), three delayed gastrointestinal bleeding. The final histological result was fibrosis and inflammatory tissue in 7 patients, low-grade dysplasia in 20 patients, high-grade dysplasia or in situ carcinoma in 10 patients, invasive adenocarcinoma in 1 patient, and somatostatinoma in 2 patients (concordance of 72% with the initial histology). The resection was complete in 39 patients (93%). Three patients had additional surgery because of positive margin of resection or bad histology criteria. The median of follow-up in 33 patients with a complete resection was of 15 months, and we did not note any recurrence in 29 patients (88%)., Conclusion: Endoscopic ampullectomy is an efficient treatment for superficial lesions of the papilla, despite a significant but rarely severe morbidity. Preoperative EUS is mandatory, preoperative histology is advisable. Long-term follow-up is necessary.

Background: Somatostatinomas are rare neuroendocrine tumours with an annual incidence of 1 in 40 million. They arise in the pancreas or periampullary duodenum. Most are clinically non-secretory and do not cause the somatostatinoma syndrome. Many are metastatic at presentation and their management is typically multimodal., Case Histories: Four cases of somatostatinoma are described. Two patients with periampullary disease presented with biliary obstruction, one with frank jaundice and one with incidental bile duct obstruction on investigation of hepatitis B. Each patient had type 1 neurofibromatosis and resection of the somatostatinoma by means of a pylorus-preserving proximal pancreaticoduodenectomy has resulted in long-term survival. Another two patients with metastatic pancreatic somatostatinomas presented with abdominal pain. Contrasting management illustrates current treatment strategies that are dependent in part on the distribution of the disease., Discussion: The pathophysiology, presentation, clinical associations and role of diagnostic imaging are discussed for periampullary and pancreatic neuroendocrine tumours. Operative treatment has an important role in both the curative and palliative settings in conjunction with appropriate medical treatments and these are described. Management options depend on the extent of the disease and the cases are used to illustrate the rationale of such strategies.

Somatostatinomas are extremely rare endocrine tumors, and those with diameters above 2 cm are reported to increase the risk of metastasis significantly. We report a case of a large functional somatostatinoma in the pancreatic tail without metastases. A 46-year-old woman with a history of recurrent mild upper abdominal pain and diarrhea for 10 months was admitted to our hospital. Multiple-phase spiral computed tomography revealed a 10 cm x 8 cm, ill-defined, elliptic mass in the body and tail of the pancreas. There was a slightly heterogeneous enhancement on hepatic arterial phase and isodensity to the pancreatic parenchyma with small dotted necrosis within the middle region of the mass on hepatic portal venous and parenchymal phase, with patent splenic vein, dilated collaterals at the splenic hilum and no dilated pancreatic duct, resembling a diffuse infiltration tumor. To the best of our knowledge, this is the first description of multiple-phase spiral computed tomography findings of a functional somatostatinoma in the pancreatic tail and the largest thus far on reported computed tomography, with some differences compared with the previous reports.

Somatostatinoma is a rare somatostatin-producing endocrine tumor, probably malignant. Due to its nonspecific symptoms such as vague abdominal pain, weight loss, or occult clinical features, misdiagnosis occurs. We report a case of pancreatic somatostatinoma with severe hypoglycemia. The patient had experienced severe hypoglycemic attacks for 11 months periodically. Contrast computed tomography scan revealed an isodensity mass about 2 cm in the head of the pancreas. Ultimately, a local excision was carried out as the tumor was located exactly on the surface of the pancreas. Somatostatinoma was established after immunohistochemical technique. The patient led a normal life without any complaint at 1 year follow-up.

A 24-year-old female complaining of diarrhea and back pain was admitted to hospital where a tumor of the pancreatic head was revealed on a computed tomography (CT) scan. Abdominal ultrasonography, CT and celiac angiography revealed a hypervascular lesion on the pancreas. An endocrine tumor, particularly a somatostatinoma, was suspected and hormone levels in the blood were examined. Serum hormone levels were normal, so FDG-PET was performed. An abnormally high accumulation of FDG was detected on the FDG-PET image at the head of the pancreas, and the SUV of the lesion was 3.2, so the mass was considered to be malignant on FDG-PET. Pylorus-preserving pancreatoduodenectomy was performed with a preoperative diagnosis of malignant endocrine tumor. The resected specimen revealed a massive, yellowish-white tumor of the pancreas head measuring 50x 45x38mm. Histologically, the tumor was a malignant islet-cell tumor, and immunohistochemically the tumor stained with an anti-somatostatin antibody, but not with antibodies against glucagons, insulin or vasoactive intestinal polypeptide. The patient was discharged after the operation and has remained well without recurrence for 5 years. Liver metastatic tumors, however, appeared 6 years after the operation.

Somatostatinomas are rare tumors; ampullary somatostatinomas are very rare. We report a case of a small pure somatostatin-producing neuroendocrine tumor of ampulla of Vater in a 54-year-old woman with neither neurofibromatosis nor somatostatinoma syndrome, "incidentally" discovered during an abdominal computed tomography. The patient initially refused other adjunctive exams but after 2 years she was admitted, presenting with itch, night sweats, severe fatigue, and unintentional weight loss. The size of the tumor (1.5 cm) and the other radiologic findings had not changed since the abdominal CT scan 2 years before. The somatostatin, gastrin, glucagons, serotonin, vasoactive intestinal peptide, dopamine, norepinephrine, epinephrine, and calcitonin plasma levels were normal. ERCP-obtained biopsies revealed a neuroendocrine tumor with psammoma bodies; immunohistochemical profile was positive for chromogranin and somatostatin. The patient underwent surgery; intraoperative histologic examination of lymph nodes sampling of perihepatic and periduodenal lymph nodes was negative for metastasis. We performed, therefore, a transduodenal ampullectomy. The patient continues to do well at 3 years' follow-up with no evidence of local or distance recurrence of disease.

The authors report a large duodenal somatostatinoma, a very rare tumor entity. A 8.5 cm globular mass in the area of the unicate process of the pancreas was detected in a 45 year old caucasian female by computerized tomography. The patient had only mild complaints. Initial treatment consisted of right pancreatectomy with preservation of the pylorus. Histological evaluation rendered a diagnosis of low-grade malignant neuroendocrine carcinoma with expression of somatostatin, respectively of somatostatinoma arising in the duodenum and infiltrating into the pancreas. 26 months after the initial surgery liver and lymph node metastases were detected and surgically removed. This case confirms that duodenal somatostatinomas are very difficult to diagnose preoperatively because of unspecific symptoms. Most duodenal somatostatinomas are found incidentally. Treatment of choice is radical surgical resection with a possible cure in early stages of the disease. Even a large tumor as ours is resectable with negative surgical margins. Management of recurrent or metastatic disease is also surgical. Additional chemotherapy and supportive care may be beneficial for the patient.

Somatostatinomas are extremely rare periampullary malignant neuroendocrine tumors that may be associated with von Recklinghausen disease or type-I neurofibromatosis. Duodenal somatostatinomas are distinguished from pancreatic somatostatinomas by their frequent association with type-I neurofibromatosis and typically absence of somatostatinoma syndrome. We report a very rare and atypical case of malignant duodenal somatostatinoma presenting with somatostatinoma syndrome in association with type-I neurofibromatosis.

Background: Somatostatinomas involving the gastrointestinal tract are extremely rare neoplasms that typically present with indolent, nonspecific symptoms in the absence of systemic neuroendocrine manifestations that characterize the somatostatinoma syndrome. Because of a relatively large size at the time of presentation (average diameter of 5 cm) and common location within the head of the pancreas, the Whipple procedure (pancreaticoduodenectomy) serves as the predominant modality for curative and palliative surgical approaches., Methods: Two cases of somatostatinoma involving the minor duodenal papilla with concomitant pancreatic divisum were reviewed, with a general overview of this unique islet cell tumor., Results: Unlike typical somatostatinomas, these two tumors were subcentimeter in size but were associated with synchronous regional metastasis., Conclusions: Somatostatinomas are often associated with regional and/or portal metastases at the time of diagnosis, and only 60% to 70% of surgical cases result in complete tumor resection. Predictors of an unfavorable prognosis include size >3 cm, poor cytological differentiation, regional and/or portal metastasis, and incomplete surgical resection. Even in the presence of synchronous metastases, the 5-year overall survival for patients with somatostatinoma is approximately 40%. Currently, there are no clinical trials demonstrating significant improvement in survival with the use of adjuvant therapy.

We report a case of somatostatinoma of the papilla of Vater with multiple gastrointestinal stromal tumors in a patient with von Recklinghausen's disease (VRD). A 64-year-old woman who had had recurrent attacks of acute pancreatitis and cholangitis was found, on gastroduodenal endoscopy, to have a tumor of the papilla of Vater and multiple submucosal tumors of the stomach and duodenum. Numerous submucosal tumors were observed in the stomach, duodenum, and jejunum, and total excision of the papilla of Vater and resection of the duodenal and jejunal submucosal tumors was performed. The tumor of the papilla of Vater showed the histologic appearance of a dense proliferation of tumor cells in acinar form, from the duodenal mucosa to the muscle layer, and psammoma bodies were revealed within the tumor. Immunohistologically, the tumor cells were intensely positive for somatostatin. The submucosal tumors of the duodenum and jejunum were negative for smooth muscle actin, s-100, and neuron-specific enolase (NSE), and positive for CD34 and c-kit, and they were diagnosed as gastrointestinal stromal tumors (GISTs) according to the strict definition. The only 25 cases of papilla of Vater somatostatinoma associated with VRD to have been reported in the English-language literature since 1982 are reviewed, as well as our own case.

Unlabelled: Preoperative localization of pancreatic neuroendocrine tumors with traditional imaging fails in 40-60% of patients. Endoscopic ultrasound (EUS) is highly sensitive in the detection of these tumors. Previous reports included relatively few patients or required the collaboration of multiple centers. We report the results of EUS evaluation of 82 patients with pancreatic neuroendocrine tumors., Methods: We prospectively used EUS early in the diagnostic evaluation of patients with biochemical or clinical evidence of neuroendocrine tumors. Patients had surgical confirmation of tumor localization or clinical follow-up of >1 yr., Results: Eighty-two patients underwent 91 examinations (cases). Thirty patients had multiple endocrine neoplasia syndrome type 1. One hundred pancreatic tumors were visualized by EUS in 54 different patients. The remaining 28 patients had no pancreatic tumor or an extrapancreatic tumor. Surgical/pathological confirmation was obtained in 75 patients. The mean tumor diameter was 1.51 cm and 71% of the tumors were < or =2.0 cm in diameter. Of the 54 explorations with surgical confirmation of a pancreatic tumor, EUS correctly localized the tumor in 50 patients (93%). Twenty-nine insulinomas, 18 gastrinomas, as well as one glucagonoma, one carcinoid tumor, and one somatostatinoma were localized. The most common site for tumor localization was the pancreatic head (46 patients). Most tumors were hypoechoic, homogenous, and had distinct margins. EUS of the pancreas was correctly negative in 20 of 21 patients (specificity, 95%). EUS was more accurate than angiography with or without stimulation testing (secretin for gastrinoma, calcium for insulinoma), transcutaneous ultrasound, and CT in those patients undergoing further imaging procedures. EUS was not reliable in localizing extrapancreatic tumors., Conclusions: In this series, the largest single center experience reported to date, EUS had an overall sensitivity and accuracy of 93% for pancreatic neuroendocrine tumors. Our results support the use of EUS as a primary diagnostic modality in the evaluation and management of patients with neuroendocrine tumors of the pancreas.

Background/aims: The endocrine tumors of the pancreas are rare diseases and there is no established standard therapy for the liver metastasis of pancreatic endocrine tumors. In this study, the therapy for the pancreatic endocrine tumors was evaluated., Methodology: The endocrine pancreas tumors of 13 patients had been surgically treated. All primary tumors were completely resected. The liver metastasis was recognized in 4 patients. Partial resection of the liver was performed in 2 patients. Lipiodol-transcatheter arterial embolization was performed for synchronous unresectable liver metastases in the other 2 patients., Results: The patients with no liver metastases survived without recurrence (max: 18.8 yr; mean follow-up: 9.2 yr). The patient with resected synchronous solitary liver metastasis died of recurrent multiple liver metastases 5 months after surgery. The other patient with the metachronous liver metastasis completely resected survived 13.9 years. In the 2 patients with unresectable numerous liver metastases, after lipiodol-transcatheter arterial embolization, tumor necrosis rate was more than 90% in both cases and serum gastrin level was normalized., Conclusions: Complete resection of liver metastasis is favorable, whereas lipiodol-transcatheter arterial embolization is effective for unresectable liver metastases from pancreatic endocrine tumors as palliation. Complete resection of the primary site is recommended even in the cases with unresectable numerous liver metastases.

Somatostatinomas are rare functioning neoplasms usually arising in the pancreas and duodenum. We report a case of somatostatinoma in a 42-year-old male with neither neurofibromatosis nor somatostatinoma syndrome. A large tumor in the descending duodenum had given rise to multiple lymph node metastases. An additional 31 duodenal somatostatinoma cases were also reviewed. Most originated in the descending part of the duodenum, with the ampulla and peri-ampullary area as the most common sites (60%). Frequent manifestations were abdominal pain (25%), jaundice (25%), or cholelithiasis (19%), the latter two reflecting obstruction of the bile duct by tumors. Only two cases showed a possible somatostatinoma syndrome (6%). The tumors with metastases, lymph nodes (10) and liver (2), were significantly larger than average than those without (2.91 +/- 1.49 cm vs 1.36 +/- 0.71 cm, P < 0.05). With a cut-off point of 2.0 cm, diagnostic accuracy for metastasis was 77.78% with 87.50% specificity and 63.64% sensitivity. The smallest tumor with metastases was 0.8 cm and the largest without metastases was 3.0 cm. These results indicate that duodenal somatostatinomas are malignant by nature and the risk of metastasis significantly increases with tumors larger than 2.0 cm.

Background: Somatostatin receptor scintigraphy (SRS) and octreotide therapy have both changed the management of gastroenteropancreatic endocrine tumours, but very few data are available on the use of SRS and octreotide to visualise and treat somatostatinomas., Method: The results of SRS and octreotide treatment in three somatostatinoma patients were examined., Results: SRS was able to detect extensive hepatic involvement in patient 1, one hepatic and one pancreatic lesion in patient 2, and one hepatic lesion in patient 3. Octreotide therapy (0.5 mg/day subcutaneously) was effective in decreasing plasma levels of somatostatin in all three patients. Symptoms (diabetes and diarrhoea) were greatly improved in the two patients with "somatostatinoma syndrome"., Conclusion: The study shows that somatostatinoma, like most other gastroenteropancreatic endocrine tumours, possesses functioning somatostatin receptors.

Objective: This study evaluates the diagnostic and therapeutic implications of somatostatin-receptor scintigraphy in the management of patients with proven or high clinical suspicion of gastroenteropancreatic endocrine tumors., Methods: Forty-one patients were studied by planar and tomographic imaging at 4 h and 24 h after 111In-pentetreotide injection. Scintigraphic findings were compared with computed tomography, and in several patients also with ultrasound, angiography, biopsy, and/or surgery, when performed., Results: Among 23 patients with carcinoid tumor, three of nine primary tumors were initially identified by scintigraphy. Unsuspected mesenteric metastases found on scintigraphy in three patients led to octreotide treatment. Scintigraphic detection of multiple metastases in a patient with thyroid metastasis of bronchial carcinoid spared her an unnecessary total thyroidectomy. Among 18 patients with 19 islet-cell tumors, scintigraphy detected three of five insulinomas, whereas computed tomography identified only one. Receptor positivity in an islet-cell tumor (vipoma?) with no metastases on the scan led to surgical removal of the primary tumor. Receptor-positive metastases of gastrinoma (two of three patients), glucagonoma (two of three patients), and parathyroid hormone-related peptide-producing tumor (one patient) led to octreotide treatment. Nonvisualization of metastases of a glucovipoma led to chemotherapy., Conclusions: Somatostatin-receptor scintigraphy contributes to the management of patients with gastroenteropancreatic tumors in the following ways: 1) localization of a primary occult tumor, allowing surgical removal; 2) staging of the disease for optimal therapy-surgical excision or systemic treatment; and 3) identification of receptor status of the metastases for octreotide treatment or chemotherapy.

This article describes the visualization of a pancreatic somatostatinoma and liver metastases using 111In-pentetreotide imaging in a patient with somatostatinoma syndrome. A 61-yr-old woman with gallbladder stones, diabetes, weight loss, diarrhea and steatorrhea, immunohistochemical diagnosis of somatostatinoma (liver biopsy) and high plasma values of somatostatin was studied by somatostatin receptor scintigraphy. Six sites of focal abnormal 111In-pentetreotide hyperfixation were found: three in the liver and three in the pancreatic area. This case report demonstrates that in vivo detection of somatostatinoma with somatostatin receptor imaging is possible in the presence of high levels of circulating somatostatin, suggesting that receptor downregulation has not occurred.

A phase 3 multicenter clinical study was performed to investigate the efficacy, safety and usefulness of MP-1727, a novel tumor imaging agent which binds to somatostatin receptors, in 23 patients with gastrointestinal hormone producing tumor. The efficacy was graded effective or very effective in 16 cases (76.2%) out of 21 cases who could be evaluated. Positive predictive accuracy was 77.8% (7/9) for carcinoids, 100% (5/5) for gastrinomas and 40.0% (2/5) for insulinomas. In three cases, tumor lesions which had been unknown were detected by MP-1727 scintigraphy. The consistent ratio between scintigraphically positive sites and preinjection localizations was 82.0% (41/50 sites) in total. Although adverse drug reactions were observed in two cases, the safety was graded 'not problematic at all' in all of 23 cases. These results show that MP-1727 is a very useful radiopharmaceutical for detection and localization of gastrointestinal hormone producing tumors.

Objective: The imaging features of somatostatinoma are described in four patients., Materials and Methods: Four patients, ranging in age from 24 to 57 years, with somatostatinoma were examined. Ultrasonography (US) and CT were performed in all four patients; MRI and angiography were performed in three patients., Results: Three patients had a tumor in the pancreas and one in the papilla major. In two cases there were metastases in the liver, and one had bone and lymph node metastases. Pancreatic tumor and metastases were equally well detected by CT and MRI. One tumor in the tail of the pancreas was initially missed by US. Pancreatic tumor and metastases were echo poor. Angiography showed one vascular and one avascular tumor in the pancreas. Chronic obstructive pancreatitis was seen on CT and MRI in the patient with the tumor in the papilla major. Angiography and US failed to demonstrate this tumor; CT and MRI showed the tumor in retrospect. Primary tumor and metastases are of low signal intensity on T1-weighted imaging and increased signal intensity on T2-weighted imaging., Conclusion: Somatostatin-producing endocrine tumors are mainly located in the pancreas but can also be present in extrapancreatic organs such as the duodenum and papilla of Vater resulting in chronic obstructive pancreatitis. Duodenal somatostatinomas are associated with von Recklinghausen neurofibromatosis. Radiologic and MRI features of somatostatinomas resemble those of other neuroendocrine tumors. Radiological techniques and MRI often fail to demonstrate the tumors in the duodenum. The diagnosis in cases of duodenal localization can be established by endoscopic techniques.

Somatostatinoma is the rarest of the pancreatic islet cell tumors with only eight previously reported cases. We report a recent case in a 62-year-old man including CT findings and 1 year follow-up.