PAX8 Expression in well-differentiated pancreatic endocrine tumors: correlation with clinicopathologic features and comparison with gastrointestinal and pulmonary carcinoid tumors.

PAX (paired box) genes encode a family of transcription factors that regulate organogenesis and cell-lineage specification in multiple organ systems. In the pancreas, PAX proteins play a critical role in islet cell differentiation. We recently observed that islet cells show strong, diffuse staining for PAX8 by immunohistochemistry. However, PAX8 expression has not previously been examined in pancreatic endocrine tumors (PETs). The purpose of this study was to evaluate PAX8 expression in PETs, and to correlate expression with clinical and pathologic features and behavior. PAX8 expression in other well-differentiated neuroendocrine tumors (WDNETs) was also studied. In total, 190 tumors were evaluated: 156 primary WDNETs (63 PETs, 31 ileal, 5 duodenal, 5 gastric, 19 appendiceal, 13 rectal, and 20 pulmonary carcinoid tumors) and 34 liver metastases (18 PETs and 16 ileal carcinoid tumors). PAX8 was positive in 42/63 (67%) primary PETs. Expression of PAX8 was significantly associated with WHO category 1.1 ("benign" behavior) compared with category 1.2 (uncertain behavior) or 2 (well-differentiated endocrine carcinoma) (positive in 100%, 64%, and 52% of tumors, respectively; P<0.05). PAX8-positive PETs were also significantly smaller and more often clinically functional; PAX8-negative tumors were more frequently associated with liver metastases. PAX8 expression was not associated with patient age, gender, MIB1 index, or lymph node metastases. PAX8 expression was detected in 0/20 (0%) pulmonary, 1/5 (20%) gastric, 5/5 (100%) duodenal, 0/31 (0%) ileal, 4/19 (21%) appendiceal, and 11/13 (85%) rectal carcinoid tumors. Among the liver metastases, PAX8 was positive in 9/18 (50%) metastatic PETs compared with 0/16 (0%) metastatic ileal carcinoid tumors. In summary, PAX8 is expressed in normal pancreatic islet cells and in a high proportion of primary and metastatic PETs. In the GI tract, PAX8 is positive in the majority of duodenal and rectal carcinoid tumors, and in a minor subset of appendiceal and gastric carcinoids. PAX8 expression is absent in ileal and pulmonary carcinoid tumors. PAX8 immunostaining may be helpful in determining the primary site for a WDNET metastatic to the liver, as ileal (PAX8 negative) and pancreatic (PAX8 positive) tumors most often present as a metastasis from an occult primary. PAX8 may also be a prognostic marker in PETs, as loss of expression is associated with malignant behavior.

Pancreatic islet cell carcinoma presenting with concurrent Cushing's and Zollinger-Ellison syndromes: case series and literature review.

Cushing's syndrome and Zollinger-Ellison syndrome occur occasionally as a result of neuroendocrine cancers. The concurrence of the two syndromes has been considered to confer a poor clinical and therapeutic outcome. In this study, we are reviewing two patients with pancreatic islet cell carcinomas and with both Zollinger-Ellison and Cushing's syndromes, one followed up for more than 5 years, and the other still receiving therapy, 5 years since diagnosis. A literature review showed that surgery has limited utility as the majority of these patients had metastases at the time of diagnosis. Proton-pump inhibitors, ketoconazole, and somatostatin antagonists have a major role in controlling symptoms. Interferon and systemic chemotherapeutic agents play a role in the management of metastatic and fast-growing cases. Chemoembolization and bland embolization show encouraging results in controlling liver metastases. The latter was used effectively and more than once in the two patients presented herein. On the basis of recent molecular genetics studies, target therapy may be helpful, however, ongoing trials will define it's utility. As the data confers a worse prognosis versus other pancreatic neuroendocrine tumors, the relatively favorable outcome of the two patients reported herein may reflect the impact of multiple therapeutic modalities.

Immunohistochemical and clinicopathological correlation of the metastasis-associated gene 1 (MTA1) expression in benign and malignant pancreatic endocrine tumors.

Pancreatic endocrine tumors are rare tumors with unpredictable clinical behavior. No histological features or immunohistochemical markers reliably predict malignant progression and the molecular basis of progression of pancreatic endocrine tumors remains unknown. The metastasis-associated gene 1 is thought to play a role in transcription repression and estrogen receptor interaction and is overexpressed in several human cancers, including endocrine neoplasms. The purpose of this study was to analyze the expression of metastasis-associated gene 1 in pancreatic endocrine tumors for its possible role in malignant progression. Twenty-seven pancreatic endocrine tumors were identified from our archive. The mean age at presentation was 57 years (range 28-86); the male/female ratio was 1.25 to 1, and the mean size was 4.5 cm (0.1-18 cm). The clinical follow-up data were examined and tumors were classified according to the 2004 World Health Organization criteria as benign behavior (WHO 1.1), uncertain behavior (WHO 1.2), well-differentiated endocrine carcinoma (WHO 2), and poorly differentiated endocrine carcinoma (WHO 3). Histopathological and immunohistochemical stains were evaluated and metastasis-associated gene 1 expression scored semiquantitatively as absent (1+), weak (2+), moderate (3+), or strong (4+). Statistical analysis was performed using Kruskal-Wallis nonparametric analysis of variance with a significance level of 0.05. Metastasis-associated gene 1 expression was significantly higher in malignant tumors (n=17) with a mean staining intensity of 3.8 compared with 2.9 in benign tumors (n=10, P=0.046). The expression levels were significantly associated with WHO class (P=0.028), as well as size of tumor (P=0.029), and mitotic rate (P=0.035). Metastasis-associated gene 1 expression was associated with local invasion with borderline significance (0.062). We show that metastasis-associated gene 1 expression is significantly associated with malignant behavior in pancreatic endocrine tumors. This may suggest a potential role for metastasis-associated gene 1 in the malignant progression and metastasis and its use as biomarker for malignant pancreatic endocrine tumors.

Functional MRI evaluation of tumor response in patients with neuroendocrine hepatic metastasis treated with transcatheter arterial chemoembolization.

OBJECTIVE: The purpose of this study was to evaluate contrast-enhanced and diffusion-weighted MRI changes in neuroendocrine tumors treated with transcatheter arterial chemoembolization (TACE). MATERIALS AND METHODS: Sixty-six targeted lesions in 26 patients (18 men, eight women; mean age, 57 years) with hepatic metastasis of neuroendocrine tumors treated with TACE were retrospectively analyzed. MRI studies were performed before and after TACE. Imaging features included tumor size, percentage of enhancement in the arterial and portal venous phases, and diffusion-weighted imaging apparent diffusion coefficients (ADCs) of the tumor, liver, and spleen. Tumor response to treatment was recorded according to World Health Organization criteria and Response Evaluation Criteria in Solid Tumors. Liver function tests were performed, and clinical performance was assessed before and after treatment. Statistical analysis included paired Student's t tests and Kaplan-Meier survival curves. RESULTS: Mean tumor size and percentage enhancement in the arterial and portal venous phases decreased significantly after treatment (p < 0.0001). The tumor ADC increased from 1.51 x 10(-3) mm2/s before treatment to 1.79 x 10(-3) mm2/s after treatment (p < 0.0001), but the ADCs for the liver and spleen remained unchanged. Despite the change in tumor size, no patient in this cohort achieved complete response according to World Health Organization criteria and Response Evaluation Criteria in Solid Tumors. Partial response was achieved in only 27% and 23% of the patients according to the respective criteria. Results of liver function tests and performance status also remained unchanged. The mean survival period for all patients was 78 months. CONCLUSION: Contrast-enhanced and diffusion-weighted imaging showed significant changes after TACE of neuroendocrine tumors and can be used to assess response of targeted tumors.

[Case of pancreatic endocrine tumor associated with Cushing's syndrome].

A 78-year-old woman was admitted complaining of edema of the bilateral lower extremities and face. Computed tomography (CT) and ultrasonography (US) of her abdomen revealed a pancreatic tumor and multiple liver metastases. After admission, hypokalemia and muscle weakness and edema of the bilateral lower extremities rapidly worsened. The diagnosis of Cushing's syndrome was established based on clinical and biochemical data and endocrine studies. We thought that the primary tumor was a pancreatic endocrine tumor based on the liver tumor biopsy findings, and that the pancreatic tumor and liver metastatic tumors were ectopic ACTH-producing tumors. A case of pancreatic endocrine tumor associated with Cushing's syndrome is relatively rare. We summarize previous reports.

Prognostic and biological significance of cytokeratin 19 in pancreatic endocrine tumours.

AIM: The prognosis of well-differentiated pancreatic endocrine tumours (PETs) is difficult to establish on a histological basis. The expression of cytokeratin (CK19) has recently been proposed as an indicator of unfavourable outcome. However, this finding still needs to be verified and to be compared with more frequently used prognosticators such as proliferative indices, vascular and/or perineural invasion. The aim of this study was to evaluate the prognostic value of CK19 expression in PETs. METHODS AND RESULTS: One hundred and forty-five PETs were studied using two different anti-CK19 monoclonal antibodies (BA17 and RCK108). The results were statistically compared with proliferation markers, vascular and perineural invasion and the presence of metastases. On univariate analysis, CK19 immunoreactivity correlated with prognosis only when it was detected with the RCK108 antibody and only in the whole group of PETs and in insulinomas. Conversely, it did not predict survival in non-functioning neoplasms. Ki67 index, mitotic count, vascular and perineural invasion were all statistically correlated with prognosis. On multivariate analysis, only the Ki67 index and metastases were independent prognosticators. CONCLUSIONS: CK19 expression correlates with patient survival only when detected with the RCK108 antibody and mainly in insulinomas. Ki67 index and metastases represent the only two independent predictors of survival.

The predictive value of CK19 and CD99 in pancreatic endocrine tumors.

Prediction of behavior in pancreatic endocrine tumors (PETs) is reliant on clinicopathologic features. However, there remains a cohort of PETs that behave aggressively despite showing indolent pathologic features. Recently, it has been suggested that CK19 and CD99 are sensitive ancillary markers that predict outcome in PETs. An analysis of 54 PETs and 2 resected liver metastases was undertaken to examine the relationship of CK19 and CD99 and the pathologic criteria in the WHO classification of PETs. CK19 was found to correlate with mitotic count (>5/50 high-power fields), an MIB-1 labeling index of > or =2%, lymphovascular/perineural permeation, lymph node involvement, and liver spread. Although not statistically significant, CK19-negative tumors tended to be smaller than the average tumor size in the series (2.5 vs. 3.6 cm). CD99 did not show any significant correlation with any of the WHO criteria. Tumors that are confined to the pancreas with low mitotic count and MIB-1 labeling index, tended to be CD99-positive. Both CK 19 (negative) and CD99 (positive) correlated with insulin-positive PETs. In conclusion, CK 19 may prove to be a useful ancillary diagnostic test in the routine work-up of PETs. CD99 does not appear to be as useful. There is no compelling evidence, from our study, to suggest that both these markers may be used in concert to predict the behavior of PETs.

Intraductal spread by metastatic islet cell tumor (well-differentiated pancreatic endocrine neoplasm) involving the breast of a child, mimicking a primary mammary carcinoma.

Metastases to the breast are rare, accounting for an estimated 1% to 2% of malignant breast neoplasms. The key histopathologic features supporting a metastasis to the breast have been stated to be the absence of elastosis, presence of a pushing border (circumscribed lesion), multiple satellite foci, lymphatic emboli, and, most importantly, the absence of an in situ carcinoma component. We report a unique case of a pancreatic islet cell tumor metastatic to the breast of an 18-year-old girl. Clinically, the patient was thought to have a mammary primary because on her initial biopsy, the metastasis grew within mammary ducts and colonized a complex sclerosing lesion, simulating an in situ component. However, review of slides from the prior pancreatic neoplasm, review of slides from the subsequent mastectomy, and use of immunohistochemistry allowed recognition of the lesion as a metastasis, which proved to be the first clinical manifestation of a systemic relapse. To our knowledge, this is the second case of islet cell tumor reported to metastasize to the breast, and the first report of a metastasis proven to have grown within existing ducts of the breast by immunohistochemistry.

Differences in survival for patients with resectable versus unresectable metastases from pancreatic islet cell cancer.

Well-differentiated islet cell tumors can be associated with aggressive biology, resulting in early metastases to the liver. This study was carried out to determine whether survival for patients with malignant islet cell tumors and synchronous liver metastases is affected by complete surgical resection. Thirty-one patients with synchronous liver metastases from islet cell cancer underwent surgical exploration with the intent for complete tumor resection, and all patients underwent resection of the pancreatic primary. The patients were divided into two groups, those with resectable versus unresectable liver metastases. Twenty-six of 31 (84%) patients underwent complete resection of both the primary tumor and all liver metastases, and 5 (16%) patients underwent only complete resection of the pancreatic primary without liver resection. To extirpate the primary tumor, a pancreaticoduodenectomy was performed in 11 of the 26 (42%) completely resected patients and in 4 of the 5 (80%) incompletely resected patients, P = NS. The remainder of the patients underwent distal pancreatectomy. There were no statistical differences in primary tumor size, lymph node metastases, or adjuvant treatments between patients with resected and unresected liver metastases. The median overall survival for the completely resected group was 78 months, longer than the 17 months for the group with unresectable liver metastases (P = 0.06). Complete tumor resection (or the tumor biology that allows such complete resection) affords a survival advantage to patients with metastatic islet cell tumors of the pancreas. Patterns of liver metastases from islet cell tumors, specifically multiple bilobar metastases that are not amenable to resection and/or ablation, predict a poor outcome despite resection of the primary pancreatic tumor.

Hepatic arterial embolization and chemoembolization for the treatment of patients with metastatic neuroendocrine tumors: variables affecting response rates and survival.

BACKGROUND: The objective of this study was to determine the prognostic variables that influence response and survival in patients with metastatic neuroendocrine tumors who are treated with hepatic arterial embolization (HAE) or chemoembolization (HACE). METHODS: Patients with metastatic neuroendocrine tumors who underwent HAE or HACE were included in this retrospective study. Follow-up imaging studies were compared with baseline imaging to determine the radiologic response. Progression-free survival (PFS) and overall survival (OS) were calculated using the Kaplan-Meier method. Univariate and multivariate analyses were performed to assess the prognostic variables that affected response and survival. RESULTS: The study included 69 patients with carcinoid tumors and 54 patients with pancreatic islet cell carcinomas. Patients who had carcinoid tumors had a higher response rate (66.7% vs. 35.2%; P = 0.0001) and had longer PFS (22.7 mos vs. 16.1 mos; P = 0.046) and OS (33.8 mos vs. 23.2 mos; P = 0.012) compared with patients who had islet cell carcinomas. For patients with carcinoid tumors, multivariate analysis identified male gender as the only independent risk factor for poor survival (P = 0.05). Octreotide was predictive marginally for PFS (P = 0.06). Patients who were treated with HAE had a higher response rate than patients who were treated with HACE (P = 0.004). For patients with islet cell carcinoma, an intact primary tumor, > or = 75% liver involvement, and extrahepatic metastases were associated with reduced OS in the univariate analysis; the presence of bone metastases was the only risk factor (P = 0.031) in the multivariate analysis. Patients who were treated with HACE had a prolonged OS (31.5 mos vs. 18.2 mos) and improved response (50% vs. 25%) compared with patients who were treated with HAE, although the differences did not reach statistical significance. CONCLUSIONS: Patients with carcinoid tumors had better outcomes than patients with islet cell carcinomas. The addition of intraarterial chemotherapy to HAE did not improve the outcome of patients with carcinoid tumors, but it seemed to benefit patients with islet cell carcinomas. In patients who had carcinoid tumors, male gender predicted a poor outcome, and a trend toward prolonged PFS was observed in patients who received concomitant octreotide. An intact primary tumor, extensive liver disease, and bone metastases were associated with reduced survival in patients with islet cell carcinomas.

Pathological assessment of pancreatic endocrine tumors for metastatic potential and clinical prognosis.

The prognostic significance of several pathological factors (tumor size, mitotic index, Ki-67 labeling index, and vascular invasion) and expression of exocrine markers (CA19-9, CEA, AFP, and trypsin) in pancreatic endocrine tumors was studied. A total of 20 specimens of metastasizing (n = 10) and non-metastasizing (n = 10) tumors were subjected to histological and immunohistochemical examination. The metastasizing tumors showed significantly larger size, higher Ki-67 labeling index, increased number of mitotic cells, and more frequent vascular invasion in comparison with the non-metastasizing tumors. It was difficult to determine the effect of individual factors on clinical outcome because of slow disease progression in almost all cases. Numerous mitotic cells and widespread necrosis, however, were thought to indicate a poor prognosis, and tumors with these characteristics were regarded as high-grade malignant endocrine carcinomas. In one case, one-third of the tumor tissue comprised trypsin-positive cells, the outcome was comparatively poor, and the behavior of the tumor resembled that of mixed acinar-endocrine carcinoma. A simple multifactorial approach may be effective for the identification of tumors at increased risk of metastasis, but it remains difficult to determine clinical prognosis. It is essential to at least distinguish high-grade endocrine carcinomas from the more common endocrine tumors.

Fluorouracil, doxorubicin, and streptozocin in the treatment of patients with locally advanced and metastatic pancreatic endocrine carcinomas.

PURPOSE: The role of systemic chemotherapy in the management of pancreatic endocrine carcinoma (islet cell carcinoma; PEC) is an area of considerable controversy. Response rates ranging from 6% to 69% have been reported for streptozocin-based chemotherapy. We retrospectively studied 84 patients with locally advanced or metastatic PEC who had been treated with fluorouracil, doxorubicin, and streptozocin (FAS) to determine the objective response rate, duration of progression-free survival (PFS), and duration of overall survival (OS). PATIENTS AND METHODS: Eligible patients had histologic or cytologic confirmation of their tumor and measurable disease on computed tomography or magnetic resonance imaging scans. Response to treatment was evaluated in this study using the new international criteria proposed by the Response Evaluation Criteria in Solid Tumors Committee. RESULTS: Sixty-one of the patients were male and 23 were female, with a median age of 54 years (range, 24 to 78 years). The response rate (RR) to FAS was 39%, with a median response duration of 9.3 months. The 2-year PFS rate was 41%, and the 2-year OS rate was 74%. The extent of liver metastatic disease correlated with a worse PFS (P = .01 by log-rank test) and a worse OS (P < .0001 by log-rank test). Analyses showed that metastatic replacement of more than 75% of the liver and prior chemotherapy were independently associated with inferior PFS. CONCLUSION: Patients with locally advanced or metastatic PEC who are treated with FAS may have a reasonable RR, and responders may experience longer PFS and OS. The volume of metastases in the liver is the most important predictor of outcome.

Natural history of a patient with malignant nonfunctioning islet cell tumor associated with unresectable multiple liver metastases.

Islet cell tumors of the pancreas are uncommon. Approximately 15% of islet cell tumors are nonfunctioning and have a higher malignancy rate than their functioning counterparts. Though, because of the rarity of malignant nonfunctioning islet cell tumors, the natural history of a patient with this tumor has not been clearly defined. We describe a young patient with unresectable malignant nonfunctioning islet cell tumor associated with multiple liver metastases. He was treated with palliative therapies to improve his quality of life, but did not undergo surgical removal of tumors or systemic chemotherapy. He survived for 46 months since laparotomy for histological diagnosis. Our findings may represent the natural history of patients with unresectable malignant nonfunctioning islet cell tumor, and suggest that palliative therapy may contribute not only to the improvement of a patients' quality of life but also the prolongation of survival.

Laparoscopic resection of a pancreatic polypeptidoma with a solitary liver metastasis.

Pancreatic neuroendocrine tumor is an uncommon disease, and surgery is the only potentially curative treatment even when there is hepatic metastasis. A patient undergoing concomitant laparoscopic distal pancreatectomy and hepatectomy for pancreatic polypeptidoma with a solitary liver metastasis is reported.

Metastatic islet cell carcinoma to the umbilicus: diagnosis by fine-needle aspiration.

Internal malignancies rarely metastasize to the umbilical region. The gastrointestinal tract and female genital tract are the most common primary sites. Although the pancreas is frequently involved, the majority of these metastases are adenocarcinoma. Here, we present a case of umbilical metastasis from an islet cell carcinoma diagnosed by fine-needle aspiration in a young woman 2 yr after distal pancreatectomy. This finding led to further radiological studies and surgical intervention, which revealed intraabdominal tumor spread. Neuroendocrine tumors represent a rare tumor type that can give rise to umbilical metastases. Only two cases of carcinoid tumor metastasizing to the umbilicus have been reported.

Liver metastases arising from well-differentiated pancreatic endocrine neoplasms demonstrate increased VEGF-C expression.

Pancreatic endocrine neoplasms (PENs) are uncommon, generally well-differentiated neoplasms that demonstrate prominent endocrine differentiation. Although the majority of PENs remain localized, malignant spread may occur via lymphatic or hematogenous routes. Angiogenic growth factors, including the vascular endothelial growth factor (VEGF) family, have been implicated in new vessel growth and hematogenous metastases, although this has not been studied in PENs. We therefore examined 19 primary well-differentiated PENs and 7 liver metastases to determine the expression of VEGF-A and its family member VEGF-C by immunolabeling analysis. VEGF-A immunoreactivity was evident only in scattered cells throughout all lesions. VEGF-C, however, demonstrated low-to-moderate expression in primary PENs by semiquantitative histoscore analysis (factor of labeling intensity by percentage of positive cells), with significantly increased expression in liver metastases (mean histoscore indices: primary PEN, 4.7 versus liver metastases, 9.5; Student's t test; P =.002773). Microvascular density of primary PENs and liver metastases did not appear to linearly correlate with VEGF-C expression. Examination of the VEGF-C-specific receptors VEGFR-2/KDR/Flk-1 and VEGFR-3/Flt-4 demonstrated intense endothelial immunoreactivity for VEGFR-2, as well as VEGFR-2 and -3 expression on the majority of neoplastic cells, suggesting a possible role in autocrine/paracrine neoplastic growth regulation. We postulate that the upregulation of VEGF-C may be involved in PEN progression and metastases, although not via a direct proangiogenic mechanism.