The role of morphometry in predicting prognosis in pancreatic islet cell tumors

The functioning side of the pancreas: a review on insulinomas

PURPOSE

Insulinomas are a rare type of neuroendocrine tumors, originating in the pancreas, difficult to diagnose and to treat. Due to its rarity, insulinomas are a not well-known pathological entity; thus, the diagnostic process is frequently a medical challenge with many possible differential diagnoses. The diagnostic process varies between non-invasive procedures, such as the fasting test or imaging techniques, and invasive ones. Insulinomas are rarely malignant, but the glycemic imbalance correlated with this tumor can frequently alter the quality of life of the patients and the consequent hypoglycemia can be extremely dangerous. Moreover, insulinomas can be associated with different genetic syndromes, such as Multiple Endocrine Neoplasia 1, accompanied by other specific symptoms. There are many different treatment strategies, depending on the need to control symptoms or control diseases progression, the only curative one being surgery.

METHODS AND RESULTS

We reviewed the evidences present in the literature on insulinomas and reported its main clinical characteristics and management strategies.

CONCLUSION

The aim of this review of the literature is to present the current knowledge on insulinomas, exploring the main clinical characteristics, the diagnostic tools, and the therapeutic strategies.

Increased expression of CD44v6 in endocrine pancreatic tumours but not in midgut carcinoid tumours

Aims/background-To analyse the different isoforms of CD44 in various types of endocrine pancreatic and gut carcinoid tumours and to investigate the relation between their expression and tumour dissemination. This study was prompted by the recent observation that inappropriate splicing of the CD44 gene was correlated with tumour progression and metastasis formation in a number of human cancers.Methods-Expression of CD44 isoforms was studied in 38 endocrine pancreatic tumours and gut neuroendocrine tumours using antibodies directed against products of exons v3, v4-v5, v6, v7-v8 as well as against the standard CD44 molecule (CD44H). CD44 gene expression was also analysed by reverse transcription PCR (RT-PCR) in nine endocrine and seven carcinoid tumours.Results-All gastrinomas except one (nine of 10) and about half of the other endocrine pancreatic tumours (seven of 15) expressed CD44v6. Most (10/11) midgut carcinoid tumours were CD44v6 negative, with no detectable immunostaining. CD44v3, CD44v4-v5 and CD44v7-v8 were not expressed in any of these tumours. CD44 mRNA analysis illustrated a complex splice pattern and expression of large CD44 isoforms in CD44v6 positive endocrine tumours, whereas the standard form only was detected in midgut carcinoid tumours. No correlation between CD44 variant expression and tumour metastasis was observed.Conclusions-CD44 variants encoding exon v6 are preferentially expressed both in gastrinomas and in most pancreatic endocrine tumours. In contrast to other tumours, the expression of CD44v6 in pancreatic neuroendocrine tumours does not seem to be correlated with tumour dissemination.

Predicting prognosis in gastroentero-pancreatic neuroendocrine tumors: an overview and the value of Ki-67 immunostaining

Gastroenteropancreatic neuroendocrine tumors (GEP-NETS) are unusual and rare neoplasms for which prognostic assessment and the diagnosis of malignancy, on the basis of histology alone, represent considerable challenges for the pathologist. To date, many molecular markers have been identified with a view to providing accurate and timely prediction of response to treatment and long-term survival. Proliferation remains a key feature of tumor progression, which has been widely estimated by the immunohistochemical use of the Ki-67 nuclear antigen. Given the continued difficulties inherent in prediction of malignancy in pancreatic neuroendocrine tumors (PETs) in particular, it has become unclear whether Ki-67 is truly a reliable prognostication marker. This review seeks to better establish what the consensus is on the role of the Ki-67 proliferation index as a prognostic indicator of long-term outcome in pancreatic neuroendocrine tumors. We conclude that most studies favor the utility of the Ki-67 proliferation index despite different critical percentages and in concert with other pathological parameters in the routine work-up of PETs.

Nonductal neoplasms of the pancreas

Although the majority of pancreatic neoplasms are infiltrating ductal adenocarcinomas or other neoplasms with ductal differentiation, neoplasms with acinar, endocrine, mixed, or uncertain differentiation constitute a diverse and distinctive group. The most common and best-characterized nonductal neoplasms are pancreatic endocrine neoplasm, acinar cell carcinoma, pancreatoblastoma, and solid pseudopapillary neoplasm. This review details the clinical and pathologic features of these nonductal neoplasms, highlighting diagnostic criteria including the use of specific immunohistochemical stains to define the cellular differentiation of the neoplasms.

Endocrine pancreatic tumours and helical CT: contrast enhancement is correlated with microvascular density, histoprognostic factors and survival

PURPOSE

To assess the role of contrast-enhanced helical CT in the evaluation of tumour vascularity in endocrine pancreatic tumours (EPTs), and to determine the predictive factors of malignancy of EPTs at helical CT with CT-histopathological correlation.

MATERIALS AND METHODS

Thirty-seven consecutive patients with histopathologically proven EPTs underwent dual-phase helical CT. For each tumour detected, its density relative to the surrounding parenchyma was scored on the pancreatic phase using a 5-point scale. Radiological findings were correlated with histopathological (vessel density count) and clinical follow-up findings.

RESULTS

Thirty of 37 patients had non-functioning EPTs and overall 44 tumours were detected by helical CT (mean size 38, range 5-100 mm). CT showed calcifications in 10 tumours. Calcifications were associated with well-differentiated carcinomas (90%, p = 0.02). Vascular density assessed by light microscopy was significantly correlated with tumour enhancement at the pancreatic phase (p = 0.0001). Poorly differentiated carcinomas were less vascularised than well-differentiated tumours and carcinomas (34 vs. 264 vessels/mm2, p = 0.0073). Tumour differentiation also correlated with tumour enhancement at the pancreatic phase (p = 0.0044, trend test): poorly differentiated carcinomas were hypoattenuating (71%) and isoattenuating or weakly hyperattenuating (29%), compared with well-differentiated carcinomas and tumours that were mainly moderately or strongly hyperattenuating (53%). In univariate analysis, poor tumoral differentiation, hepatic metastasis, high mitotic index, poor tumoral enhancement at the pancreatic phase and less vascularised tumours were correlated with decreased survival rate.

CONCLUSION

Enhancement of EPT at CT is correlated with tumour vascularity assessed by light microscopy. Low-enhancing EPT at CT are correlated with poorly differentiated EPT and with a decrease in overall survival.

Enteroendocrine tumors other than carcinoid: a review of clinically significant advances

Only relatively recently has there been an increased clinical recognition and characterization of the heterogeneous group of rare gastroenteropancreatic neuroendocrine neoplasms. Most have endocrine function and exhibit varying degrees of malignancy. This review summarizes the derivation of these tumors and the advances in their diagnosis and treatment over the past decade and a half. They are varied in their biological behavior and clinical courses and, depending on their cell type, can produce different hormones causing distinct clinical endocrine syndromes (insulinoma [hypoglycemia], gastrinoma [Zollinger-Ellison syndrome (ZES)], vasoactive intestinal peptideoma [VIPoma], watery diarrhea, hypokalemia-achlorhydria [WDHA], glucagonoma [glucagonoma syndrome], and so forth). In addition to surgery for cure or palliation (by excision and a variety of other cytoreductive techniques), they each are treated with anti-hormonal agents or drugs targeted to each tumor's specific product or its effects. The majority have benefited from the gut hormone-inhibiting action of somatostatin analogs. Because of their usual slow rate of growth it is recommended that, even when they are advanced and incurable, unlike in patients with common and more malignant cancers, patients with neuroendocrine tumors often can be palliated and appear to survive longer when managed with an active approach using sequential multimodality treatment. Advances in these various therapies are reviewed and the beneficial emergence of global self-help patient support groups is noted.

Cellular proliferative fraction measured with topoisomerase IIalpha predicts malignancy in endocrine pancreatic tumors

CONTEXT

Endocrine pancreatic tumors (EPTs) are rare lesions with varying biological behavior. Establishing malignancy is a challenge for clinicians and pathologists.

OBJECTIVE

To establish the role of proliferative, apoptotic, angiogenic, and hormonal markers as predictors of malignancy in EPTs.

DESIGN

Paraffin-embedded EPT samples were studied for prognostic markers.

PATIENTS

Twenty-one consecutive patients with a diagnosis of EPT.

MAIN OUTCOME MEASURES

The proliferative fraction (topoisomerase IIalpha), microvascular density (CD34), vascular endothelial growth factor expression, and estrogen receptor-beta (ERbeta) expression were studied by immunohistochemistry on all EPTs. Apoptosis was also assessed with terminal deoxynucleotidyl transferase nick-end labeling.

RESULTS

We identified 13 benign and 8 malignant tumors. Topoisomerase IIalpha was significantly increased in malignant tumors (P =.001), while there were no differences in apoptosis, microvascular density, or vascular endothelial growth factor expression in association with malignancy. No correlation could be identified between microvascular density and vascular endothelial growth factor expression, and ERbeta was not detected. A receiver operating characteristic curve for topoisomerase IIalpha disclosed that above a labeling index of 13, the test had 88% sensitivity and 100% specificity for predicting malignancy.

CONCLUSION

Cellular proliferation measured with topoisomerase IIalpha is a simple prognostic marker for malignancy in EPTs, unlike apoptosis, angiogenesis, or the presence of ERbeta, which were not associated with malignant behavior. These findings designate a defined field for future research on endocrine pancreatic carcinogenesis and a possible target for chemotherapeutic agents.

Low microvessel density is an unfavorable histoprognostic factor in pancreatic endocrine tumors

BACKGROUND AND AIMS

In many malignant tumors, intratumoral microvascular density (MVD) has been suggested to be a prognostic parameter. We aimed to provide a quantitative evaluation of intratumoral microvascular density in a large series of resected endocrine tumors of the pancreas and to evaluate the potential prognostic significance of this parameter.

METHODS

Eighty-two tumors from 77 patients have been studied. MVD was evaluated by 2 observers after CD34 immunostaining and correlated with the following parameters: WHO classification, hormonal profile, tumor size, vascular endothelial growth factor expression, occurrence of metastasis, duration of survival.

RESULTS

MVD ranged from 5 to 92 vessels/field. MVD was significantly higher in well-differentiated benign endocrine tumors than in tumors of uncertain behavior and in carcinomas. No close correlation was found between MVD and the hormonal profile. MVD was significantly higher in tumors characterized by the following histoprognostic parameters: size <2 cm, proliferation index <2%, no evidence of metastasis. No close correlation was observed between MVD and VEGF expression. Finally, a MVD <30 vessels/field was associated with the occurrence of metastasis in tumors <2 cm and/or with a proliferation index <2% and with a significantly shorter survival after surgery.

CONCLUSIONS

The quantitative analysis of microvessel density in pancreatic endocrine tumors may identify patients who, despite favorable conventional histoprognostic factors, are at risk of unfavorable evolution.

Low nuclear proliferative activity is associated with nonmetastatic islet cell tumors

CONTEXT

Traditional morphologic features of tumor aggression are of limited value in predicting the malignant behavior of endocrine neoplasms. We explored the potential value of nuclear proliferative activity (using Ki-67 immunostaining with semiquantitative scoring) in predicting the clinical behavior of pancreatic islet cell tumors (ICTs), and we correlated this characteristic with hormone expression.

OBJECTIVE

To evaluate whether Ki-67 immunostaining using a semiquantitative scoring system has value in predicting the clinical behavior of pancreatic ICTs.

DESIGN

We studied 39 pancreatic ICTs from 39 patients. Twenty-two ICTs did not metastasize in a median follow-up period of 91 months. The remaining 17 neoplasms did produce metastases (8 in liver, 7 in regional lymph nodes, and 2 in peritoneum). Immunohistochemistry was performed using antibodies to Ki-67 and pancreatic hormones (insulin, glucagon, gastrin, somatostatin, pancreatic polypeptide, vasoactive intestinal polypeptide, and corticotropin). A semiquantitative Ki-67 grading system was followed. The nuclear proliferative activity, as determined by a positive reaction for Ki-67, was considered low (<5% of cells staining positively), intermediate (5%-25% of cells staining positively), or high (>25% of cells staining positively).

RESULTS

The majority of the nonmetastatic ICTs (16 cases, 73%) demonstrated either negative or low staining for Ki-67 (P <.001). Conversely, all metastatic ICTs expressed at least an intermediate-grade reaction. High nuclear proliferative activity was only seen in metastatic neoplasms (3 cases, 17%). There was no relationship between immunoexpression of pancreatic hormones and nuclear proliferative activity by either group of tumors.

CONCLUSION

An ICT with low nuclear proliferative activity is unlikely to metastasize, whereas high proliferative activity is associated with a metastatic phenotype. Immunohistochemical assessment of Ki-67 using a semiquantitative scoring system is a simple and reliable detection method of cellular proliferative activity in ICTs of the pancreas.

Protocol for the examination of specimens from patients with endocrine tumors of the pancreas, including those with mixed endocrine and acinar cell differentiation: a basis for checklists. Cancer Committee of the College of American Pathologists

No Abstract Available

Prognostic factors in patients with endocrine tumours of the duodenopancreatic area

BACKGROUND

The development of endocrine tumours of the duodenopancreatic area (ETDP) is thought to be slow, but their natural history is not well known. The aim of this study was to determine the factors that influence survival of patients with ETDP.

PATIENTS/METHODS

Eighty two patients with ETDP (44 non-functioning tumours, 23 gastrinomas, seven calcitonin-secreting tumours, four glucagonomas, three insulinomas, one somatostatinoma) followed from October 1991 to June 1997 were included in the study. The following factors were investigated: primary tumour size, hormonal clinical syndrome, liver metastases, lymph node metastases, extranodular/extrahepatic metastases, progression of liver metastases, local invasion, complete resection of the primary tumour, and degree of tumoral differentiation. The prognostic significance of these factors was investigated by uni- and multi-variate analysis.

RESULTS

Twenty eight patients (34%) died within a median of 17 months (range 1-110) from diagnosis. Liver metastases (p = 0.001), lymph node metastases (p = 0.001), progression of liver metastases (p < 0.00001), lack of complete resection of the primary tumour (p = 0.001), extranodular/extrahepatic metastases (p = 0.001), local invasion (p = 0.001), primary tumour size > or = 3 cm (p = 0.001), non-functioning tumours (p = 0.02), and poor tumoral differentiation (p = 0.006) were associated with an unfavourable outcome by univariate analysis. Multivariate analysis identified only liver metastases (risk ratio (RR) = 8.3; p < 0.0001), poor tumoral cell differentiation (RR = 8.1; p = 0.0001), and lack of complete resection of the primary tumour (RR = 4.8; p = 0.0007) as independent risk factors. Five year survival rates were 40 and 100% in patients with and without liver metastases, 85 and 42% in patients with and without complete resection of primary tumour, and 17 and 71% in patients with poor and good tumour cell differentiation respectively.

CONCLUSION

Liver metastases are a major prognostic factor in patients with ETDP. Progression of liver metastases is also an important factor which must be taken into account when deciding on the therapeutic approach. The only other independent prognostic factors are tumoral cell differentiation and complete resection of the primary tumour.

Canine neuroendocrine tumors of the pancreas: a study using image analysis techniques for the discrimination of metastatic versus nonmetastatic tumors

Canine pancreatic neuroendocrine tumors were studied using different image analysis techniques (nuclear image histometry, analysis of argyrophilic proteins of nucleolar organizer regions, determination of the mouse anti-Ki 67 antigen proliferation index, and DNA densitometry) to correlate their biological behavior with objective phenotypic markers. The methods were compared to determine the best method for distinguishing between metastatic and nonmetastatic tumors. Discrimination between the two types of tumor was possible using nuclear image histometry in combination with morphometric analysis of argyrophilic proteins of nucleolar organizer regions. In contrast, the mouse anti-Ki 67 antigen proliferation index, DNA measurement, and immunohistochemical parameters revealed no significant difference between the two types of tumors.

Pancreatic endocrine tumour: a 22-year clinico-pathological experience with morphological, immunohistochemical observation and a review of the literature

The clinico-pathological features of 53 Chinese patients (27 males; 26 females) with pancreatic endocrine tumours were studied. The age range was from 14 to 78 years old (mean: 48 years) with the modal peak in the sixth decade for both sexes. Pancreatic endocrine tumours accounted for 14% of the primary pancreatic tumours operated on in Queen Mary Hospital. The autopsy incidence was 0.11%. Seventy-two per cent (38 cases) of the tumours were clinically functioning, comprising 33 insulinomas, three gastrinomas and two glucagonomas. A rare case of malignant gastrinoma associated with Cushing's syndrome was also documented. The functional tumours were seen in the younger patients. The calculated annual incidence of clinically significant tumours was approximately 0.2 per 100,000 population. There was no correlation between the site, functional status and histological patterns of the tumours. Seventy-two per cent of the tumours showed a trabecular pattern. Calcification was present in 5.7% (three cases); two such cases being gastrinomas. Amyloid was found in 25% of tumours, chiefly (92%) in the insulinomas. The main difficulty encountered in diagnosis was distinguishing between solid and cystic tumours of the pancreas. The incidence of malignancy was 15% and the histological features were poor predicative indicators of malignant potential. The metastatic pancreatic endocrine tumours were often detected in the liver and lymph nodes. Immunohistochemical stains showed evidence of multi-hormone production in 18% of cases and all tumours showed a positive reaction to at least one of the six markers, namely, neuron-specific enolase (NSE), chromogrannin (CG), synaptophysin (SYN), insulin (INS), glucagon (GLU) or somatostatin (SOM). The three panendocrine markers (NSE, SYN, CG) were satisfactory for initial screening of the endocrine nature of the tumours if used in combination, as 92% of tumours were positive for at least one of these three markers.

Proliferative Activity in Pancreatic Endocrine Tumors: Association with Function, Metastases, and Survival

Endocrine tumors of the pancreas are slow-growing lesions, yet one-third to one-half will metastasize. It is generally accepted that histopathologic features do not reliably predict metastatic potential or outcome. We investigated whether proliferative activity, as determined by MIB-l labeling, correlated with tumor type, metastasis, or patient survival. Formalin-fixed sections of pancreatic endocrine tumors were immunohistochemically stained for the MIB-l antibody against Ki-67 using the avidin-biotin complex technique. Labeling index (LI) was determined by counting 1000 consecutive tumor cells in an area of greatest staining intensity at x400 and expressed as a percentage. The study group included 37 patients, including 10 gastrinomas, 9 insulinomas, 4 glucagonomas, 2 VlPomas, and 12 nonfunctioning tumors. Twenty-one patients had metastases, primarily to regional lymph nodes and the liver. Five patients had MEN I. MIB-1 LI was significantly greater in the nonfunctioning tumors (mean 20S%) than in the functioning tumors (mean 51%) (p = 0.01). LI for functional tumors (insulinomas 64%, glucagonoma 44%, gastrinomas 32%, VlPomas 32%) were similar to each other, MIB-1 was significantly higher in those tumors that metastasized (mean 15.6%) compared to those that did not (mean 31%), (p = 0.04). All tumors with MIB-1 LI >10% developed metastases. Logistic regression showed that MIB-1 was a significant predictor of metastases (p = 0.003) after adjusting for functional status. MIB-1 LI also correlated with outcome in that those patients with MIB-1 LI >/=10% had a mean survival of 19 mo compared to 72 mo for those with levels <10% (p = 0.0001). Results of the proportional hazards model showed that MIR-1 remained a significant (p = 0.03) and independent predictor of survival times after adjustment for tumor size and functional status. Higher MIB-1 LI values were significantly associated with shorter survival times. In conclusion, MIB-1 LI appears to be a useful indicator of metastatic potential and is predictive of outcome in PET.

Prognostic criteria in nonfunctioning pancreatic endocrine tumours

To identify prognostic subgroups among non-functioning (nonsyndromic) pancreatic endocrine tumours, a series of 61 tumours were analysed systematically for macroscopic, histopathological and immunohistochemical variables potentially predictive of malignancy. High-grade nuclear atypia, elevated mitotic rate and multifocal necrosis allowed us to separate 5 poorly differentiated carcinomas from 56 well differentiated tumours. Among the latter, 29 well-differentiated carcinomas showing gross local invasion or metastases were identified. Vascular or perineural microinvasion, Ki67 proliferative index > 2%, mitotic rate > or = 2, size > or = 4 cm, capsular penetration, nuclear atypia, lack of progesterone receptors and presence of calcitonin were among the variables correlated with malignancy. The first two were the most sensitive and specific. Their presence or absence was used in the 27 tumours lacking evidence of malignancy at the time of surgery to separate 11 cases with increased risk of malignancy (in 2 of which metastases developed during follow-up) from 16 cases with limited risk. The resulting four prognostic groups of non-functioning pancreatic endocrine tumours (limited- and increased-risk tumours, well-differentiated carcinomas and poorly differentiated carcinomas) showed distinct survival curves, which were significantly affected by vascular microinvasion, Ki67 proliferative index and metastases.

Endocrine tumors of the pancreas: Ki-67 immunoreactivity on paraffin sections is an independent predictor for malignancy: a comparative study with proliferating-cell nuclear antigen and progesterone receptor protein immunostaining, mitotic index, and other clinicopathologic variables

Prediction for malignancy of pancreatic endocrine tumors (PET) is often a formidable challenge for the pathologist. The authors evaluated the role of the proliferative activity and progesterone receptor protein (PgRP) in predicting prognosis and survival of PET. Twenty-three functioning (FT) and 31 nonfunctioning tumors (NFT) were evaluated for mitotic activity and immunostaining for Ki-67 antigen, proliferating cell nuclear antigen (PCNA), and progesterone receptor protein (PgRP) on paraffin sections. The results were expressed as a percentage (index) of immunoreactive or mitosing cells. All 54 cases showed immunostaining for Ki-67 and PCNA, and valuable mitotic index, whereas only a fraction of tumors (25 of 54 cases) exhibited PgRP expression. Ki-67 and PCNA indexes correlated strongly between themselves and to mitotic index, whereas an inverse relationship was observed between cell proliferation and PgRP status in both FT and NFT. Although univariate analysis showed that Ki-67, PCNA, mitotic and PgRP indexes, stage, immunoreactivity for hormones other than insulin, diameter, and nonfunctioning type of tumor were statistically correlated to survival, Cox's regression method let only Ki-67 index emerge as an independent predictor of survival using a cutoff value of 5% in both FT and NFT.

Proliferation Markers and Their Uses in the Study of Endocrine Tumors

A growing body of literature supports the view that the proliferative activity (PA) of tumor cells is an important prognostic indicator for a variety of different tumors. We examined the role of PA in diagnosis and prediction or malignancy of endocrine tumors (ETs) of pituitary gland, pancreas, thyroid, parathyroid glands, adrenal glands, paraganglia, gastroenteric tract, and lung. The data in the literature indicate that the assessment of PA is not a diagnostic indicator of malignancy especially at the individual case level, whereas it can be useful for identifying subsets of malignant tumors with different aggressiveness potential, as well as for choosing therapeutic options in metatstatic lesions. We hope that, in the near future, multiparametric approaches including PA markers, cell growth and differentiation factors, and oncogenes will yield valuable information for diagnosis and prognosis of ETs also in individual cases.

Aneuploid islet cell tumor with late metastasis

An unusual case of insulin producing islet cell tumor is reported which recurred after a 16 yr interval. In most instances malignancy of islet cell tumors is impossible to assess morphologically or functionally but depends on the recognition of metastases. Nuclear DNA analysis provides significant prognostic and biological information in a number of solid human tumors. Retrospective computerized nuclear image analysis of the primary tumor in the present case showed an aneuploid DNA profile similar to that seen in the metastasis. It appears that ploidy studies may be useful in predicting malignant potential of islet cell tumors.

Malignant potential of aneuploid pancreatic endocrine tumours

Evaluation of the malignant potential of pancreatic endocrine tumours is difficult by histological criteria alone. Nuclear deoxyribonucleic acid (DNA) cytometric analysis can provide significant prognostic and biological information in a number of solid human tumours. Thus, the DNA profiles and nuclear parameters of 39 patients with pancreatic endocrine tumours diagnosed from 1969 to 1989 were studied, using computerized video image analysis. Of the 39 patients with tumours, 27 cases did not have evidence of metastatic disease at the time of investigation. The majority of these (N = 21) showed a diploid profile. Five were aneuploid and one was tetraploid. In the 12 tumours that proved malignant, three had tissue of both primary tumour and the metastases analysed; six had material only from the primary tumour, although metastatic disease was established clinically; and another three only had tissue from the secondary tumour studied. The majority of the malignant cases were aneuploid (N = 7); three were diploid; one showed a diploid primary but an aneuploid secondary, and one showed a hyperdiploid pattern. The percentage of nuclei with a DNA content greater than 5N (5CER) did not seem to contribute further to the assessment nor did the means of the nuclear areas and shape factors. It appears that ploidy studies may be useful in predicting malignant potential of pancreatic endocrine tumours. There is a high rate of immunostaining for insulin by benign pancreatic endocrine tumours and this may be a useful adjunct to distinguish them from their malignant counterparts. However, there is no statistically significant correlation between the expression of various hormones and the DNA ploidy of tumour cells.

Nucleolar and dispersed nucleolar organiser regions (NORs) in differentiating neoplastic from atypical non-neoplastic lesions of the pancreas

Our objective was to compare the accuracy of differentiation of pancreatic carcinoma from the benign ductular aggregation of chronic pancreatitis using two methods, nuclear morphometric analysis and modified argyrophilic nucleolar organiser region (AgNOR) staining for nucleoli and dispersed NORs (AgNU staining). We evaluated 35 metastatic or invasive lesions of pancreatic carcinoma with low-grade atypia, 16 lesions of ductular aggregation and 12 lesions of proper epithelium. Four parameters, consisting of the size of nucleus: mean area, mean minor axis, mean major axis and mean perimeter, and two parameters of AgNu staining: mean number of AgNu-stained dots per nucleus (equal to mean number of nucleoli and dispersed NORs) and mean area of the largest AgNu-stained dot (equal to mean area of the largest nucleolus) of pancreatic carcinomas were significantly larger than those of ductular aggregations and of proper epithelia. In the discriminant analysis of four parameters of nuclear size, the discrimination of carcinomas was correct in 82.9% and that of ductular aggregations in 81.3%. Discriminant analysis by two parameters of AgNu staining showed 2 correct discrimination of lesions in 88.6% and 100%. Thus, AgNu staining was more accurate than nuclear morphometric analysis in discriminating a pancreatic carcinoma from ductular aggregation.

How malignant is malignant? A brief review of the microscopic assessment of human neoplasms, and the prediction of whether they will metastasize and kill

This review examines ways in which histopathologists can attempt to predict the degree of malignancy from the microscopic examination of surgically removed samples of human neoplasms. These include mitotic counts, measurement of DNA content, analysis of DNA turnover, measurement of proliferation antigens, measurement of nucleolar organizing areas, counting nucleoli, morphometry of nuclei, identification of genetic change, measurement of lysis of basement membrane, and measurement of invasion in vitro. The latter two are not currently of practical value. Of the rest none is uniformly capable of predicting the degree of malignancy of a human neoplasm. After further refinement and control measurement of several such parameters may however contribute more to the prediction of malignancy than present subjective assessments.