Ectopic insulinoma in a dog with insulin-induced hypoglycemia: a case report.

A 7-year-old spayed female Shih Tzu dog was presented for evaluation of recurrent hypoglycemia. Serum insulin levels during hypoglycemia were 35.3 µIU/mL. Ultrasonography and computed tomography showed a mesenteric nodule between the kidney and the portal vein, but no pancreatic mass was observed. During surgery, the nodule had neither anatomical adhesions nor vascular connections to the pancreas. Pancreatic inspection and palpation revealed no abnormalities. Hypoglycemia improved after resection of the nodule. Histopathological examination confirmed the nodule to be an islet cell carcinoma. Although extremely rare, ectopic insulinoma should be considered as a possible cause of insulin-induced hypoglycemia in dogs.

MULTIHORMONAL ISLET CELL CARCINOMAS IN THREE KOMODO DRAGONS (VARANUS KOMODOENSIS).

Multihormonal pancreatic islet cell carcinomas were found in one female and two male captive geriatric Komodo dragons (Varanus komodoensis). Gross changes in the pancreas were visible in two of the cases. Clinical signs noted in the Komodo dragons were lethargy, weakness, and anorexia. Histologically, the tumors were comprised of nests and cords of well-differentiated neoplastic islet cells with scant amounts of eosinophilic cytoplasm and round, euchromatic nuclei, with rare mitoses. Infiltration by the islet cell tumor into the surrounding acinar tissue was observed in all cases, but no metastatic foci were seen. Multihormone expression was observed in all tumors, which labeled strongly positive for glucagon and somatostatin and focally positive for polypeptide. Pancreatic islet cell neoplasms should be considered in the differential diagnosis for geriatric Komodo dragons presenting with weakness, lethargy, and poor appetite.

Pancreatic neuroendocrine tumors: contemporary diagnosis and management.

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

Malignant-functioning neuroendocrine tumors of the pancreas: A survival analysis.

BACKGROUND: Malignant-functioning pancreatic neuroendocrine tumors (mFpNETs) are rare. Research analyzing the presentation, biological behavior, and patient outcomes of these tumors is limited. METHODS: We used the Surveillance, Epidemiology, and End Results database to identify patients with malignant insulinomas, gastrinomas, glucagonomas, vasoactive intestinal peptide secreting tumors (VIPomas), somastatinomas, and mixed islet cell tumors (MICTs). The primary endpoint of this study was to identify factors affecting survival. RESULTS: We identified 401 patients with mFpNETs. Between histologic subtypes, there were significant differences in sex and age, and in tumor size, grade, location, and stage. Median survival time for insulinomas was 12.7 years; gastrinomas, 10.2 years; glucagonomas, 7.7 years; VIPomas, 7.9 years; and MICTs, 3.4 years. Multivariable analysis showed that histology (insulinoma, gastrinoma, and VIPoma; P = .009), absence of distant metastases (P = .002), age < 50 years (P = .001), surgical intervention (P = .001), and stage I/II disease (P = .011) were independently associated with prolonged survival. Subgroup analysis demonstrated that removal of the primary tumor in stage IV mFpNETs was associated with significantly prolonged survival (P = .01). CONCLUSION: mFpNETs are rare tumors that commonly present at an advanced stage despite hormonal secretion. Primary tumor resection is associated with longer survival in stages I-III as well as stage IV tumors.

The transformation of a nonfunctioning islet cell tumor of the pancreas into a proinsulinoma under conditions of lung metastasis.

We herein report the first case of a nonfunctioning islet cell tumor that transformed into a proinsulinoma during the process of metastasis to the lungs. This phenomenon was confirmed in a 69-year-old woman with an advanced pancreatic islet cell tumor and multiple liver metastases who later developed multiple lung metastases. She underwent pancreatic resection followed by the administration of chemotherapy and survived for seven years. Although the patient initially had hyperglycemia due to diabetes mellitus, she conversely began to manifest hypoglycemic attacks 63 months postoperatively with the concomitant development of multiple lung metastases. An autopsy revealed that only the tumor in the lungs produced proinsulin; no other hormones were detected.

Osseous metaplasia within a canine insulinoma.

An 11-year-old male castrated mixed-breed dog was presented for exercise intolerance, tetraparesis, and persistent hypoglycemia. Abdominal ultrasound examination revealed 2 nodules within the right limb of the pancreas. Cytology from one nodule was consistent with a carcinoma of neuroendocrine origin, with a primary differential diagnosis of insulinoma. Histologic evaluation and immunohistochemistry for synaptophysin and insulin confirmed the diagnosis of insulinoma. Additionally, there was a solitary nodule of mineralized compact bone composing approximately 60% of the mass. To the authors' knowledge, this is the first report of osseous metaplasia within an insulinoma (islet cell carcinoma).

Population-level analysis of pancreatic neuroendocrine tumors 2 cm or less in size.

BACKGROUND: There is a paucity of evidence regarding incidence and predictors of survival in pancreatic neuroendocrine tumors (PNETs)≤2 cm in size. METHODS: Patients having undergone resection for nonfunctioning PNETs were selected from the SEER database (1988-2009) and an institutional pathology database (1996-2012). PNETs≤2 cm were compared with PNETs>2 cm. Data were analyzed with χ2 tests, ANOVA, the Kaplan-Meier method, log rank tests, and Cox proportional hazard, and binary logistic regression. RESULTS: The incidence of PNETs≤2 cm in the United States has increased by 710.4% over the last 22 years. Rates of extrapancreatic extension, nodal metastasis, and distant metastasis in PNETs≤2 cm in the SEER database were 17.9, 27.3, and 9.1%, respectively. The rate of nodal metastasis in our institutional series was 5.7%. Disease-specific survival at 5, 10, and 15 years for PNETs≤2 cm was 91.5, 84.0, and 76.8%. Decreased disease-specific survival was not associated with nodal metastasis, but rather with high grade [moderately differentiated, hazard ratio (HR) 37.2, 95% confidence interval (CI) 2.7-518.8; poorly differentiated, HR 94.2, 95% CI 4.9-1,794.4; reference, well differentiated], and minority race (Asian, HR 30.2, 95% CI 3.1-291.7; Black, HR 60.1, 95% CI 2.1-1,027.9; reference, White). CONCLUSIONS: Pancreatic neuroendocrine tumors≤2 cm are increasingly common, and the most significant predictors of disease-specific survival are grade and race. The SEER database excludes PNETs considered to be benign, and rates of extrapancreatic extension, nodal metastasis, and distant metastasis are overestimated. Small size, however, does not preclude malignant behavior.

Characterization of neuroendocrine tumors of the pancreas by real-time quantitative polymerase chain reaction. A methodological approach.

The aim of this study was to assess the suitability of using real-time quantitative PCR (RT-qPCR) to characterize neuroendocrine (NE) tumors of the pancreas. For a series of tumors, we evaluated several genes of interest, and the data were matched with the "classical" immunohistochemical (IHC) features. In 21 cases, we extracted RNA from formalin-fixed paraffin-embedded (FFPE) blocks, and in nine cases, we also extracted RNA from fresh-frozen tissue. The RT-qPCR procedure was performed using two sets of customized arrays. The test using the first set, covering 96 genes of interest, was focused on assessing the feasibility of the procedure, and the results were used to select 18 genes indicative of NE differentiation, clinical behavior, and therapeutic responsiveness for use in the second set of arrays. Threshold cycle (Ct) values were used to calculate the fold-changes in gene expression using the 2-∆∆Ct method. Statistical procedures were used to analyze the results, which were matched with the IHC and follow-up data. Material from fresh-frozen samples performed better in terms of the level of amplification, but acceptable and concordant results were also obtained from FFPE samples. In addition, high concordance was observed between the mRNA and protein expression levels of somatostatin receptor type 2A (R = 0.52, p = 0.016). Genes associated with NE differentiation, as well as the gastrin-releasing peptide receptor and O-6-methylguanine-DNA methyltransferase genes, were underexpressed, whereas angiogenesis-associated markers (CDH13 and SLIT2) were overexpressed in tissues with malignant behavior. The RT-qPCR procedure is practical and feasible in economic terms for the characterization of NE tumors of the pancreas and can complement morphological and IHC-based evaluations. Thus, the results of the RT-qPCR procedure might offer an objective basis for therapeutic choices.

Mixed acinar-endocrine carcinoma of the pancreas: new clinical and pathological features in a contemporary series.

OBJECTIVE: The objective of this study was to characterize the novel clinical and pathological features of mixed acinar-endocrine carcinoma of the pancreas. METHODS: This was a retrospective review of medical records and surgical pathology specimens of patients with a diagnosis of mixed acinar-endocrine carcinoma of the pancreas at Cedars-Sinai Medical Center between 2005 and 2011. Additional immunohistochemistry was performed on the specimens of some patients. RESULTS: Five patients were identified. The median age at presentation was 74 years (range, 59-89 years), and all patients were male. The presenting symptoms were all related to tumor mass effects. The median size of the tumor was 10 cm (range, 3.9-16 cm). Preoperative clinical diagnosis aided by fine-needle aspiration biopsy was incorrect in all 5 cases. Most tumors (3/5) exhibited predominantly endocrine differentiation without hormonal production. Only 10% to 30% of cells were truly amphicrine, whereas most were differentiated into either endocrine or acinar phenotype. The clinical behavior ranged from moderate to aggressive with postoperative survival from 2.5 months to more than 3 years. Four patients received neoadjuvant or adjuvant chemotherapy with variable responses. CONCLUSIONS: Mixed acinar-endocrine carcinoma of the pancreas appears to be not uncommon in men, may harbor predominantly endocrine component, is often misdiagnosed by cytology, and exhibits variable clinical behavior. Mixed acinar-endocrine carcinoma of the pancreas should be considered in older patients with sizable pancreatic mass and may warrant aggressive surgical resection and chemotherapy.

Streptozotocin-induced diabetic ketoacidosis in a patient with metastatic islet-cell carcinoma.

Here we report a severe life-threatening complication of treatment with streptozotocin in a patient with pancreatic island-cell carcinoma. The patient was admitted to the intensive care unit with severe diabetic ketoacidosis which needed aggressive fluid resuscitation and insulin therapy. We believe it is critical to be aware of the symptoms of diabetic ketoacidosis and monitor glucose levels during streptozotocin treatment.

Survival impact of malignant pancreatic neuroendocrine and islet cell neoplasm phenotypes.

BACKGROUND: The low incidence of malignant "functional" (F) or "nonfunctional" (NF) neuroendocrine islet cell tumors (ICTs) of the pancreas represents a challenge to precise post-therapeutic survival prediction. This study examined the survival impact of malignant pancreatic ICT morphologic subtypes. METHODS: A pancreatic ICT data set was created from a US-based population database from 1980-2004. Prognostic factors with survival impact and relationships between surgical therapy and overall survival (OS) were analyzed. RESULTS: There were 2,350 individuals with malignant ICTs. Histologic subtypes included carcinoid tumors, islet cell carcinomas, neuroendocrine carcinomas, and malignant gastrinomas, insulinomas, glucagonomas, or VIPomas. There was no difference in resection rates between FICTs and NFICTs (23% vs. 20%, P = ns). Median OS was 30 months, with group differences ranging from NE carcinomas (21) to VIPomas (96; P < 0.0001). Median OS of resected versus unresected FICTs was 172 versus 37 months, while that of NFICTs was 113 versus 18 months (P < 0.0001). Compared to neuroendocrine carcinomas, hazard ratios were: VIPomas 0.48, gastrinomas 0.65, carcinoid tumors 0.76, insulinomas 0.84, glucagonomas 0.93, and islet cell carcinomas 1.0. CONCLUSIONS: When controlled for other established prognostic parameters, histopathologic subtype assignment of pancreatic ICTs affects survival prediction. Resection is associated with superior survival for all tumor types.

Prognostic relevance of survivin in pancreatic endocrine tumors.

BACKGROUND: Better prognostic markers are needed for pancreatic endocrine tumors. Survivin is an apoptosis inhibitor that is suggested to have a negative prognostic impact in several tumor types. Contradictory data exist, especially regarding the significance of a nuclear versus cytoplasmic location of survivin. The prognostic relevance of nuclear and cytoplasmic survivin expression in pancreatic endocrine tumors-controlled for the tumor Ki-67 index, World Health Organization classification, and TNM stage-was investigated. METHODS: A total of 111 patients treated at a tertiary referral center were retrospectively evaluated. Clinical data were gathered from medical records. Immunohistochemistry for survivin and Ki-67 was performed on paraffin-embedded tissue. Univariate and multivariate Cox analyses were performed. RESULTS: Patients with tumors that had <5% survivin-positive nuclei had a mean survival of 225 months [95% confidence interval (CI) 168-281]. The corresponding figure for patients with 5 to 50% survivin-positive tumor cell nuclei was 101 months [95% CI 61-140; hazard ratio (HR) 2.4; P < 0.01) and with >50% survivin-positive nuclei 47 months (95% CI 24-71; HR 4.9; P < 0.001). Nuclear survivin expression in >50% of the tumor cells was an independent marker of a poor prognosis (HR 5.7; P < 0.01). Cytoplasmic survivin was not a significant prognostic factor in the multivariate analysis (HR 0.94; P = 0.90). CONCLUSIONS: High expression of nuclear survivin is a significant marker of a poor prognosis in patients with a pancreatic endocrine tumor.

Extended surgery for advanced pancreatic endocrine tumours.

BACKGROUND: Pancreatic endocrine tumours are often diagnosed at an advanced stage with hepatic metastasis. This study investigated whether extended resections for advanced malignant pancreatic endocrine tumours influenced disease-free and disease-specific survival. METHODS: Patients who had curative resection of pancreatic endocrine tumours were analysed retrospectively for disease-free and disease-specific survival, with a focus on the role of extended surgical resection. RESULTS: Forty-one patients were included in the analysis, 13 of whom underwent extended surgical resection in addition to pancreatic resection. This included partial liver resection in nine patients, portal vein resection in three, partial gastric resection in five and liver transplantation in three patients. There were no deaths in hospital or within 30 days. Median follow-up was 40 (range 2-239) months. Thirty-five, 24 and 13 patients survived more than 1, 3 and 5 years respectively. Patients who underwent extended resection had similar disease-specific survival to those who had pancreatic resection alone (hazard ratio (HR) 1·50, 95 per cent confidence interval (c.i.) 0·35 to 6·35; P = 0·581) but with a higher frequency of complications (odds ratio (OR) 4·28, 95 per cent c.i. 1·04 to 17·62; P = 0·044). Among patients with liver metastases, the mortality rate was higher in those in whom liver resection was not possible than in patients who had liver resection (HR 9·24, 1·00 to 85·18; P = 0·049). Patients who had liver resection had similar disease-specific survival to those without liver metastases (HR 0·84, 0·09 to 7·57; P = 0·877). CONCLUSION: Extended surgical resection for locally advanced and metastatic pancreatic endocrine tumours is feasible with encouraging disease-specific survival.

Xenon-inhalation computed tomography for noninvasive quantitative measurement of tissue blood flow in pancreatic tumor.

BACKGROUND AND AIMS: The purpose of this prospective study was to demonstrate the ability to measure pancreatic tumor tissue blood flow (TBF) with a noninvasive method using xenon inhalation computed tomography (xenon-CT) and to correlate TBF with histological features, particularly microvascular density (MVD). METHODS: TBFs of pancreatic tumors in 14 consecutive patients were measured by means of xenon-CT at diagnosis and following therapy. Serial abdominal CT scans were obtained before and after inhalation of nonradioactive xenon gas. TBF was calculated using the Fick principle. Furthermore, intratumoral microvessels were stained with anti-CD34 monoclonal antibodies before being quantified by light microscopy (×200). We evaluated MVD based on CD34 expression and correlated it with TBF. RESULTS: The quantitative TBF of pancreatic tumors measured by xenon CT ranged from 22.3 to 111.4 ml/min/100 g (mean ± SD, 59.6 ± 43.9 ml/min/100 g). High correlation (r = 0.885, P < 0.001) was observed between TBF and intratumoral MVD. CONCLUSION: Xenon-CT is feasible in patients with pancreatic tumors and is able to accurately estimate MVD noninvasively.