Pancreatic somatostatinoma diagnosed preoperatively: report of a case.

CONTEXT: Somatostatinoma is a rare neoplasm of the pancreas. Preoperative diagnosis is often difficult. CASE REPORT: We report a 72-year-old woman with a pancreatic head tumor measuring 37 mm in diameter, and enlargement of the lymph nodes on the anterior surface of the pancreatic head and the posterior surface of the horizontal part of the duodenum. Laboratory data showed an elevated plasma somatostatin concentration. Examination of a biopsy specimen of the pancreatic head mass obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) showed histopathological features of a neuroendocrine tumor. Immunohistochemical staining showed that the tumor cells were positive for somatostatin, leading to a preoperative diagnosis of pancreatic somatostatinoma. The patient underwent pylorus-preserving pancreaticoduodenectomy. The plasma somatostatin concentration decreased progressively after surgery. CONCLUSIONS: A rare case of pancreatic somatostatinoma with lymph node metastases was presented. Immunohistochemical analysis of a biopsy specimen obtained by EUS-FNA was useful for preoperative diagnosis.

Lymphatic vessel endothelial hyaluronan receptor 1 immunocytochemical staining for pancreatic islets and pancreatic endocrine tumors.

OBJECTIVES: Immunocytochemical staining for lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) is able to recognize lymphatic vessel endothelium and pancreatic endocrine cells (PETs). Pancreatic endocrine tumors were studied for LYVE-1 immunocytochemical staining compared with normal pancreatic islets to detect possible presence of LYVE-1 in PETs. METHODS: Twenty-five cases of primary and metastatic PETs were immunocytochemically stained for LYVE-1, including insulinomas, glucagonomas, somatostatinoma, pancreatic polypeptidomas, gastrinomas, and nonfunctioning tumors. With routinely formalin-fixed and paraffin-embedded tissues, LYVE-1 immunostaining was performed with polyclonal goat antihuman LYVE-1. RESULTS: All normal pancreatic islet cells were positive for LYVE-1, whereas 2 cases of 25 PETs, 1 each of gastrinoma and nonfunctioning tumor, were positive for LYVE-1, retaining immunocytochemical reactivity of islet cells. CONCLUSIONS: Normal pancreatic islets were positive for LYVE-1, whereas only 2 of 25 PETs were positive, suggesting that most PETs lost LYVE-1 or contained below detectable levels of LYVE-1. The presence of LYVE-1 in pancreatic islets and in some PETs may suggest structure-function relationship of LYVE-1/lymphatic vessel in hormone synthesis and secretion.

Expression of somatostatin receptor types 1-5 in 81 cases of gastrointestinal and pancreatic endocrine tumors. A correlative immunohistochemical and reverse-transcriptase polymerase chain reaction analysis.

Somatostatin receptors (SSTRs) have been extensively mapped in human tumors by means of autoradiography, reverse-transcriptase polymerase chain reaction (RT-PCR), in situ hybridization (ISH) and immunohistochemistry (IHC). We analyzed the SSTR type 1-5 expression by means of RT-PCR and/or IHC in a series of 81 functioning and non-functioning gastroenteropancreatic (GEP) endocrine tumors and related normal tissues. Moreover, we compared the results with clinical, pathological and hormonal features. Forty-six cases (13 intestinal and 33 pancreatic) were studied for SSTR 1-5 expression using RT-PCR, IHC with antibodies to SSTR types 2, 3, 5 and ISH for SSTR2 mRNA. The vast majority of tumors expressed SSTR types 1, 2, 3 and 5, while SSTR4 was detected in a small minority. Due to the good correlation between RT-PCR and IHC data on SSTR types 2, 3, and 5, thirty-five additional GEP endocrine tumors were studied with IHC alone. Pancreatic insulinomas had an heterogeneous SSTR expression, while 100% of somatostatinomas expressed SSTR5 and 100% gastrinomas and glucagonomas expressed SSTR2. Pre-operative biopsy material showed an overlapping immunoreactivity with that of surgical specimens, suggesting that the SSTR status can be detected in the diagnostic work-up. It is concluded that SSTRs 1-5 are heterogeneously expressed in GEP endocrine tumors and that IHC is a reliable tool to detect SSTR types 2, 3 and 5 in surgical and biopsy specimens.

Duodenal somatostatinoma of the ampulla of vater diagnosed by endoscopic fine needle aspiration biopsy: a case report.

BACKGROUND: Duodenal somatostatinoma is a rare neuroendocrine neoplasm. A better prognosis can be obtained if these tumors are resected at an early clinical stage. Endoscopic punch biopsy has been the method most commonly used for the preoperative diagnosis of neuroendocrine duodenal tumors. To the best of our knowledge, endoscopic fine needle aspiration biopsy (FNAB) of duodenal somatostatinoma has not been reported before. CASE: A 41-year-old, black female presented with upper gastrointestinal bleeding as well as elevated bilirubin, liver enzymes and glucose. Computed tomography, esophagogastroduodenoscopy and endoscopic retrograde cholangiopancreatography (ERCP) detected a mass at the region of the ampulla of Vater partially obstructing the pancreatic duct. The initial punch biopsy yielded only intestinal mucosa. Subsequent endoscopic FNAB suggested the diagnosis of a neuroendocrine neoplasm, as confirmed by additional punch biopsies. Immunohistochemical and electron microscopic studies disclosed somatostatin production by the tumor, which was resected through a modified Whipple procedure. The patient recovered fully. CONCLUSION: This case demonstrates the usefulness of endoscopic FNAB in diagnosing submucosal gastrointestinal neuroendocrine tumors.

Neuropeptide Y and neuropeptide Y 3-36: isolation from human pancreatic endocrine tumours.

Using an antiserum raised to the C-terminal region of neuropeptide Y (NPY) which does not cross-react with pancreatic polypeptide (PP), immunoreactivity has been detected in two different endocrine tumours of the human pancreas in concentrations permitting isolation and structural analysis. In a clinically-typical gastrinoma, resected from the head of pancreas, the concentration of NPY immunoreactivity was 3.4 nmol/g. Reverse phase HPLC analysis of extracts of this tumour resolved a single immunoreactive peptide coeluting with synthetic human NPY. The molecular mass of the isolated peptide, determined by mass spectroscopy, was 4270 Da, which was in close agreement with that derived from the deduced primary structure of human tumour NPY (4271.7 Da), obtained by gas-phase sequencing. A somatostatinoma, resected from the region of the ampulla of Vater, contained 3.8 nmol/g of NPY immunoreactivity and isolation of this immunoreactive peptide followed by structural analyses, indicated a molecular structure consistent with NPY 3-36. These data suggest that NPY immunoreactivity detected in human pancreatic endocrine tumours is molecularly heterogenous, a finding which may be of relevance in the symptomatology of such tumours as attenuation of the N-terminus of this peptide generates receptor selectivity.

Exocrine pancreatic insufficiency and pancreatic fibrosis due to duodenal somatostatinoma in a patient with neurofibromatosis.

A case of duodenal somatostatinoma is described in a patient with Von Recklinghausen neurofibromatosis. The patient presented with exocrine pancreatic insufficiency, probably due to distal obstruction of the pancreatic duct by the tumor. Preoperative evaluation with calcium-pentagastrin and tolbutamide stimulation tests were nondiagnostic. At laparotomy, local excision of the tumor was performed. Pathological findings were compatible with duodenal somatostatinoma, causing pancreatic fibrosis. Somatostatin extracted from the tumor coeluted with the somatostatin-14 standard on high performance liquid chromatography (HPLC).

von Recklinghausen's disease associated with somatostatin-rich duodenal carcinoid (somatostatinoma), medullary thyroid carcinoma and diffuse adrenal medullary hyperplasia.

This report describes the concomitant occurrence of a somatostatin-rich duodenal carcinoid, a medullary thyroid carcinoma and a diffuse adrenal medullary hyperplasia in a patient with von Recklinghausen's disease. A 50-year-old Japanese man died from lung metastasis of a malignant schwannoma. In addition to extensive viscero-cutaneous neurofibromatosis, two different types of neuroendocrine tumors were found in the duodenum and thyroid gland at autopsy. The duodenal tumor, which was located in the second portion, showed the histologic appearance of a carcinoid tumor with glandular differentiation and psammoma-bodies. Immunohistochemically the tumor cells were intensely positive for somatostatin. The thyroid tumor was composed of nests of tumor cells arranged in an endocrine pattern, and showed immunoreactivity for calcitonin. A review of the literature revealed no previously reported case of concomitant occurrence of duodenal somatostatinoma and medullary thyroid carcinoma in a single patient with von Recklinghausen's disease. Morphometric analysis of adrenal glands disclosed the presence of diffuse medullary hyperplasia. Thus, the present case exhibited a similarity in some respects with multiple endocrine neoplasia (MEN) syndrome, Type IIa or IIb.