Differential diagnostic patterns of lung neuroendocrine tumours

Metastatic Neuroendocrine Neoplasms of Unknown Primary: Clues from Pathology Workup

Simple Summary

While most neuroendocrine neoplasms are indolent and slow-growing tumors, subsets of cases will spread beyond the tissue of origin. Given the rather slow progress, some lesions are incidentally discovered as metastatic deposits rather than primary masses. In these cases, a biopsy is often taken to allow the pathologist to identify the tumor type and possibly the primary tumor site via microscopic examination. In this review, the authors present a simplified guide on how to approach metastatic neuroendocrine tumors from a pathologist’s perspective.

Abstract

Neuroendocrine neoplasms (NENs) are diverse tumors arising in various anatomical locations and may therefore cause a variety of symptoms leading to their discovery. However, there are instances in which a NEN first presents clinically as a metastatic deposit, while the associated primary tumor is not easily identified using conventional imaging techniques because of small primary tumor sizes. In this setting (which is referred to as a “NEN of unknown primary”; NEN-UP), a tissue biopsy is often procured to allow the surgical pathologist to diagnose the metastatic lesion. If indeed a metastatic NEN-UP is found, several clues can be obtained from morphological assessment and immunohistochemical staining patterns that individually or in concert may help identify the primary tumor site. Herein, histological and auxiliary analyses of value in this context are discussed in order to aid the pathologist when encountering these lesions in clinical practice.

An analysis of 130 neuroendocrine tumors G3 regarding prevalence, origin, metastasis, and diagnostic features

Limited data exist on high-grade neuroendocrine tumors (NETs G3) which represent a new category among neuroendocrine neoplasms (NEN). We analyzed NETs G3 in a consultation series regarding prevalence, origin, metastasis, and diagnostic problems. Based on the WHO classification of digestive system tumors, 130 NETs G3 (9%) were identified in 1513 NENs. NET G3 samples were more often obtained from metastatic sites (69%) than NET G1/G2 samples (24%). NET G3 metastases presented most frequently in the liver (74%) and originated from the pancreas (38/90, 42%), followed by the lung (9%), ileum (7%), stomach (3%), rectum (1%), and rare sites (2%) such as the prostate and breast. The primaries remained unknown in 15%. NETs G3 had a median Ki67 of 30% that distinguished them from NECs (60%), though with great overlap. The expression of site-specific markers, p53, Rb1, and SST2 was similar in NETs G3 and NETs G1/G2, except for p53 and Rb1 which were abnormally expressed in 8% and 7% of liver metastases from NET G3 but not from NET G1/G2. NETs G3 were frequently referred as NECs (39%) but could be well distinguished from NECs by normal p53 (92% versus 21%) and Rb1 expression (93% versus 41%) expression. In conclusion, NETs G3 are frequently discovered as liver metastases from pancreatic or pulmonary primaries and are often misinterpreted as NEC. p53 and Rb1 are powerful markers in the distinction of NET G3 from NEC. Rarely, carcinomas from non-digestive, non-pulmonary organs with neuroendocrine features may present as NET G3.

Follow-Up Recommendations after Curative Resection of Well-Differentiated Neuroendocrine Tumours: Review of Current Evidence and Clinical Practice

The incidence of neuroendocrine neoplasms (NENs) is increasing, especially for patients with early stages and grade 1 tumours. Current evidence also shows increased prevalence, probably reflecting earlier stage diagnosis and improvement of treatment options. Definition of adequate postsurgical follow-up for NENs is a current challenge. There are limited guidelines, and heterogeneity in adherence to those available is notable. Unfortunately, the population of patients at greatest risk of recurrence has not been defined clearly. Some studies support that for patients with pancreatic neuroendocrine tumours (PanNETs), factors such as primary tumour (T), stage, grade (Ki-67), tumour size, and lymph node metastases (N) are of relevance. For bronchial neuroendocrine tumours (LungNETs) and small intestinal neuroendocrine tumours (siNETs), similar factors have been identified. This review summarises the evidence supporting the rationale behind follow-up after curative resection in well-differentiated PanNETs, siNETs, and LungNETS. Published evidence informing relapse rate, disease-free survival, and relapse patterns are discussed, together with an overview of current guidelines informing postsurgical investigations and duration of follow-up.

Metastatic medullary thyroid carcinoma or calcitonin-secreting carcinoid tumor of lung? A diagnostic dilemma in a patient with lung mass and thyroid nodule

Calcitonin-secreting neuroendocrine tumors are rare and have been reported in literature as case reports or case series in various organs including lung, pancreas, larynx, bladder, and ovary. These tumors have similar cytologic features and immunohistochemical profile to medullary thyroid carcinoma and thus it is difficult to distinguish them, especially when calcitonin-secreting neuroendocrine tumors are intermediate or higher grade and there is a mass lesion in the thyroid gland. Here, we report a rare case of calcitonin secreting atypical carcinoid tumor of the lung in a patient with thyroid nodule. However, after extensive ancillary studies on the thyroid gland, no tumor was detected and subsequent resection specimen revealed a pulmonary atypical carcinoid tumor with metastasis to level 11 lymph node. Being aware of this entity has significant clinical, diagnostic, and therapeutic implications and can prevent unnecessary thyroidectomies with subsequent possible morbidities.

Combining anatomic and molecularly targeted imaging in the diagnosis and surveillance of embryonal tumors of the nervous and endocrine systems in children

Combining anatomical and functional imaging can improve sensitivity and accuracy of tumor diagnosis and surveillance of pediatric malignancies. MRI is the state-of-the-art modality for demonstrating the anatomical location of brain tumors with contrast enhancement adding additional information regarding whether the tumor is neuronal or glial. Addition of SPECT imaging using a peptide that targets the somatostatin receptor (Octreoscan) can now differentiate medulloblastoma from a cerebellar pilocytic astrocytoma. Combined MRI and Octreoscan is now the most sensitive and accurate imaging modality for differentiating recurrent medulloblastoma from scar tissue. CT is the most common imaging modality for demonstrating the anatomical location of tumors in the chest and abdomen. Addition of SPECT imaging with either MIBG or Octreoscan has been shown to add important diagnostic information on the nature of tumors in chest and abdomen and is often more sensitive than CT for identification of metastatic lesions in bone or liver. Combined anatomical and functional imaging is particularly helpful in neuroblastoma and in neuroendocrine tumors such as gastrinoma and carcinoid. Functional imaging with MIBG and Octreoscan is predictive of response to molecularly targeted therapy with 131I-MIBG and 90Y-DOTA-tyr3-Octreotide. Dosimetry using combined anatomical and functional imaging is being developed for patient-specific dosing of targeted radiotherapy and as an extremely sensitive monitor of response to therapy. Both MIBG and Octreotide are now being adapted to PET imaging which will greatly improve the utility of PET in medulloblastoma as well as increase the sensitivity for detection of metastatic lesions in neuroblastoma and neuroendocrine tumors.

Bronchopulmonary neuroendocrine tumors

Bronchopulmonary neuroendocrine tumors (BP-NETs) comprise approximately 20% of all lung cancers and represent a spectrum of tumors arising from neuroendocrine cells of the BP-epithelium. Although they share structural, morphological, immunohistochemical, and ultrastructural features, they are separated into 4 subgroups: typical carcinoid tumor (TC), atypical carcinoid tumor (AC), large-cell neuroendocrine carcinoma (LCNEC), and small-cell lung carcinoma (SCLC), which exhibit considerably different biological characteristics. The clinical presentation includes cough, hemoptysis, and obstructive pneumonia but varies depending on site, size, and growth pattern. Less than 5% of BP-NETs exhibit hormonally related symptoms such as carcinoid syndrome, Cushing, acromegaly, and SIADH. SCLC is the most common BP-NET, while LCNEC is rare, approximately 10% and < or =1%, respectively, of all lung cancers. Both SCLC and LCNEC progress rapidly, are aggressively metastatic, and exhibit a poor prognosis. The incidence of BP-carcinoids (TC and AC) in the US was 1.57 of 100,000 in 2003 (an unexplained and substantial increase over the last 30 years, approximately 6% per year). No curative treatment except for radical surgery (almost never feasible) exists. The slow-growing TC exhibit a fairly good prognosis ( approximately 88%, 5-year survival), whereas AC demonstrate a 5-year survival of approximately 50%, and the highly malignant LCNEC and SCLC5-year survival of 15% to 57% and <5%, respectively. This review provides a broad overview on BP-NETs and focuses on the evolution of the disease, general features, and current diagnostic and therapeutic options.

Independent value of fascin immunoreactivity for predicting lymph node metastases in typical and atypical pulmonary carcinoids

Immunoreactivity for fascin, an actin-bundling protein related to cell motility, has been reported in breast, ovary, pancreas, skin, and non-small cell carcinomas, and associated with more advanced disease stage and poorer prognosis. Data on pulmonary neuroendocrine (NE) tumors, however, are lacking. We evaluated the expression of fascin by immunohistochemistry--using two different monoclonal antibodies--in surgical specimens of pulmonary NE tumors of all the diverse histological types from 128 consecutive patients recruited between 1987 and 2001, and investigated its relationship with the presence of lymph node metastases. Overall, fascin immunoreactivity was detected in 5% of 38 typical carcinoids (TC), 35% of 23 atypical carcinoids (AC), 83% of 40 large-cell neuroendocrine carcinomas (LCNEC), and 100% of 27 small-cell lung carcinomas (SCLC) (P<0.001), Normal NE cells or hyperplastic NE tumorlets were consistently unreactive. No statistically significant differences in fascin immunoreactivity were found between the two antibodies. In TC and AC but not high-grade NE tumors, fascin immunoreactivity closely correlated with the occurrence of lymph node metastases, the pN class and the number of involved lymph nodes (P<0.001). It was also significantly associated with an increased proliferative activity (Ki-67 labeling index >5%) (P=0.020), and with either down-regulation or altered subcellular compartmentalization of E-cadherin (P<0.001) and CD99 (P=0.030), two cell adhesion complexes in pulmonary NE tumors. At multivariate analysis, only fascin emerged as an independent predictor of lymph node metastases in this tumor group (HR 30.28; 95% confidence intervals: 1.59-574.49; P=0.023). This study indicates that fascin immunoreactivity may identify subsets of pulmonary carcinoid patients with different metastatic potential to regional lymph nodes. Targeting the fascin pathway could be a novel therapeutic strategy of pulmonary carcinoids.

Pulmonary and Peribronchial Lymph Node Tumorlets: Report of a Case and Review of the Literature

A 38-year-old man underwent a left lower lobectomy and lingulectomy for bronchiectasis. On macroscopic examination the lungs were bronchiectatic. Microscopically, multiple tumorlets were detected in the lung parenchyma. One peribronchial lymph node contained a tumorlet. We discuss the case and review the literature on this rare entity.

Neuroendocrine tumors of the bronchopulmonary tract: a reappraisal of their classification after 20 years

This article is an overview of the classification of pulmonary neuroendocrine neoplasms, their presentation, their pathologic appearance, and their clinical management. In addition, the original classification, based on histologic features, is reassessed in the light of newer areas in study, including neurosecretory products, neuroendocrine markers, ultrastructural studies, ploidy analysis, cell adhesion markers, apoptosis, oncogene mutation analysis, and genetic alterations. The histologic classification proposed in 1983 remains the single most valuable factor in establishing the diagnosis and, together with the TNM status, the prognosis of this group of interesting neoplasms.

Pulmonary neuroendocrine carcinomas. A review of 234 cases and a statistical analysis of 50 cases treated at one institution using a simple clinicopathologic classification

CONTEXT

Primary pulmonary neuroendocrine tumors are traditionally classified into 3 major types: typical carcinoid (TC), atypical carcinoid (AC), and large cell neuroendocrine carcinoma (LC) or small cell neuroendocrine carcinoma (SC). Confusion arises frequently regarding the malignant nature of TC and the morphologic differentiation between AC and LC or SC.

OBJECTIVE

To provide clinicopathologic evidence to streamline and clarify the histomorphologic criteria for this group of tumors, emphasizing the prognostic implications.

PATIENTS

To minimize variability in diagnostic criteria and treatment plans, we analyzed a group of patients whose diagnosis and treatment occurred at a single institution. We reviewed 234 cases of primary pulmonary neuroendocrine tumors and thoroughly studied 50 cases of resected tumors from 1986 to 1995.

RESULTS

On the basis of morphologic characteristics and biologic behaviors of the tumors, we agree with many previous investigators that these tumors are all malignant and potentially aggressive. Based on our accumulated data, we have modified Gould criteria and reclassified these tumors into 5 types: (1) well-differentiated neuroendocrine carcinoma (otherwise called TC) (14 cases, with less than 1 mitosis per 10 high-power fields [HPF] with or without minimal necrosis); (2) moderately differentiated neuroendocrine carcinoma (otherwise called low-grade AC) (6 cases, with less than 10 mitoses per 10 HPF and necrosis evident at high magnification); (3) poorly differentiated neuroendocrine carcinoma (otherwise called high-grade AC) (10 cases, with more than 10 mitoses per 10 HPF and necrosis evident at low-power magnification); (4) undifferentiated LC (5 cases, with more than 30 mitoses per 10 HPF and marked necrosis); and (5) undifferentiated SC (15 cases, with more than 30 mitoses per 10 HPF and marked necrosis). The 5-year survival rates were 93%, 83%, 70%, 60%, and 40% for well, moderately, and poorly differentiated, and undifferentiated large cell and small cell neuroendocrine carcinomas, respectively. We found nodal metastasis in 28% of TC in this retrospective review, a figure higher than previously recorded.

CONCLUSION

Using a grading system and terms comparable to those used for many years and used for neuroendocrine tumors elsewhere in the body, we found that classification of pulmonary neuroendocrine carcinomas as well, moderately, poorly differentiated, or undifferentiated provides prognostic information and avoids misleading terms and concepts. This facilitates communication between pathologists and clinicians and thereby improves diagnosis and management of the patient.

Loss of heterozygosity on chromosome arm 11q in lung carcinoids

Neuroendocrine lung tumors such as typical carcinoid, atypical carcinoid, small-cell lung carcinoma, and large-cell neuroendocrine carcinoma represent a variable group with different biologic characteristics and unclear genetical relationships. We investigated the pattern of allelic loss on chromosome arm 11q in 20 sporadic carcinoid tumors of the lung using 10 microsatellite markers. Loss of heterozygosity was found in 13 of 20 tumors. In 5 of 9 typical carcinoids, 3 distinct regions of allelic loss were identified: 11q13.1 (D11S1883), 11q14.3-11q21 (D11S906), and 11q25 (D11S910). Atypical carcinoids showed loss of heterozygosity at 4 different regions: the first, most proximal region at 11q13 between markers PYGM and D11S937; the second at 11q14.3-11q21 (D11S906); and the third and fourth defined by markers D11S939 (11q23.2-23.3) and D11S910 (11q25). However, the region 11q13 harboring the MEN1 gene was more frequently affected in atypical carcinoids (7 of 11) than in typical carcinoids (2 of 9). The high rate of allelic losses within chromosomal region 11q13 in atypical carcinoids emphasizes the importance of this region for tumor development. We also recognized that more aggressive atypical carcinoids defined by high mitotic counts, vascular invasion, and/or organ metastasis are combined with increased allelic losses. HUM PATHOL 32:333-338.

Expression of the chemokine receptor CXCR2 in normal and neoplastic neuroendocrine cells

BACKGROUND

Chemokines effect their proinflammatory and growth regulatory roles through interaction with serpentine receptors. One such receptor, CXCR2, binds multiple CXC chemokines, including interleukin 8, GRO-alpha, GRO-beta, GRO-gamma, and NAP-2. We have previously identified CXCR2 expression on myeloid cells, notably mature granulocytes, and projection neurons.

OBJECTIVE

To determine the expression of CXCR2 by cells of the neuroendocrine system.

DESIGN

Archival specimens from normal neuroendocrine tissues and their malignant counterparts were analyzed by immunohistochemistry with monoclonal antibodies specific for CXCR1 and CXCR2.

RESULTS

Immunohistochemical analysis revealed high-level expression of CXCR2 by cells in the pituitary, adrenal medulla, pancreatic islets, thyroid C cells, scattered Kulchitsky cells in the bronchi, and counterpart neuroendocrine cells in the stomach, small bowel, colon, and appendix. Neuroendocrine neoplasms that demonstrated high-level CXCR2 expression included (1) primary carcinoids localized to the stomach, small bowel, colon, appendix, fallopian tube, ovary, and lung; (2) atypical carcinoids of the lung; (3) metastatic carcinoids; (4) pituitary adenomas; (5) pheochromocytomas; and (6) medullary carcinomas of the thyroid. Small cell lung carcinomas, large cell neuroendocrine carcinomas of the lung, small cell carcinoma of the cervix, Merkel cell carcinomas, neuroblastomas, and malignant melanomas lacked evidence of CXCR2 expression.

CONCLUSIONS

The expression of CXCR2 by normal neuroendocrine cells and neoplastic counterparts that have retained phenotypic features of this differentiation program suggests that chemokines may play an important role in functions that are characteristic of this cell type. In addition, this raises the possibility that chemokines may modulate secretion of biologically active products of these cells and their neoplastic counterparts.

A critical examination of the immunophenotype of pulmonary sclerosing hemangioma

The authors studied a series of 21 cases of pulmonary sclerosing hemangioma (SH) to address conflicting and unconfirmed reports of immunohistologic evidence of differentiation that have been made in the literature. They found the lesional cells of SH to be epithelial membrane antigen (EMA) positive (21 of 21 cases), to be keratin positive only infrequently and focally (six of 21), and to be nonreactive for carcinoembryonic antigen, S-100, smooth muscle actin, and CD34. Faint nuclear staining was seen for estrogen receptors, whereas progesterone receptors were expressed strongly in 17 cases. Neuroendocrine markers (chromogranin A, adrenocorticotrophic hormone, human growth hormone, and calcitonin) were negative uniformly on the lesional cells except for one case in which rare chromogranin-positive cells were present and another case in which rare human growth hormone-positive cells were seen. In contrast to the general EMA-positive, keratin-negative phenotype of the lesional cells, the cells lining the papillae or air spaces within the SH were typically positive for both markers. The following other lesions were identified in the cases studied: carcinoid tumorlets (n = 2), a neuroendocrine body (n = 1), and multiple meningothelial-like nodules (n = 1). All were clearly separable from the SH on morphologic grounds. The authors interpreted these to be chance occurrences of unrelated lesions. Recognition of the phenotype of SH as EMA positive, keratin weak to negative, and negative for S-100, smooth muscle actin, and neuroendocrine markers is notable in its differential diagnosis from other lesions. This phenotype does not suggest a precise lineage or type of differentiation for SH.

Ploidy, proliferative activity, p53 and bcl-2 expression in bronchopulmonary carcinoids: relationship with prognosis

Bronchopulmonary well-differentiated neuroendocrine carcinoma (WDNEC) represents a more aggressive neoplasm than does typical carcinoid. Its biological behavior is variable and cannot be predicted on the basis of histopathological features. Nineteen typical carcinoids and 23 WDNECs were studied in order to obtain multiple parameters that should be used in the differential diagnosis between these two lesions and as prognostic markers of WDNEC. Flow-cytometry was performed on paraffin-embedded sections. Mutant p53 protein, the bcl-2 oncoprotein and the Ki-67 antigen were detected by immunohistochemical methods and evaluated quantitatively. WDNEC was more frequently aneuploid than typical carcinoid, had a higher percentage of Ki-67 positive nuclei and presented more frequently the mutant p53 protein. In WDNEC, the mutant p53 (p = 0.001), the bcl-2 oncoprotein (p = 0.002) and the high expression (> or = 16%) of Ki-67 (p = 0.0021) were associated with poor prognosis. The prognostic significance of mutant p53 and bcl-2 oncoprotein could be confirmed by Cox multiple regression survival analysis (p = 0.0005). It seems to be advisable to evaluate these features for the management of the patients affected by WDNEC.

Typical and atypical carcinoid tumors of the lung are characterized by 11q deletions as detected by comparative genomic hybridization

Neuroendocrine tumors of the lung represent a wide spectrum of phenotypically distinct entities with different biological characteristics such as typical carcinoid tumor (TC), atypical carcinoid tumor (AC), large-cell neuroendocrine carcinoma (LCNEC), and small-cell lung carcinoma (SCLC). The histogenetic relationships between TC, AC, LCNEC, and SCLC are still unclear. This study was carried out to provide cytogenetic data about pulmonary neuroendocrine tumors and to evaluate their characteristic alterations and histogenetic relations for an improved understanding of the mechanisms of tumor development. Twenty-nine paraffin-embedded tumor samples of TC (n = 17), AC (n = 6), LCNEC (n = 3), and SCLC (n = 3) were selected for isolation of tumor DNA and subsequent comparative genomic hybridization (CGH) analysis. To confirm the comparative genomic hybridization results for characteristic chromosomal imbalances, selected cases were additionally investigated by loss of heterozygosity analysis. For statistical evaluation, we also used comparative genomic hybridization data from 45 published SCLC cases. DNA underrepresentations of 11q were the most frequent findings in TC (8 of 17) and AC (4 of 6), whereas these aberrations were rare in LCNEC (1 of 3) and SCLC (0 of 3). Furthermore, AC showed DNA underrepresentation of 10q (3 of 6) and 13q (3 of 6). In contrast, SCLC and LCNEC were characterized by a different pattern of DNA losses (3p-, 4q-, 5q-, 13q-, and 15q-) and gains (5p+, 17p+, and +20). Statistical analysis revealed significantly different occurrences of 11q deletions in TC/AC versus SCLC (45 published cases of SCLC and our 3 cases; P = 0.002; Fisher's exact test). Thus, TC and AC display frequent loss of 11q material including the MEN1 gene locus, which represents a characteristic genetic alteration in these tumors. Losses of 10q and 13q sequences allow a further cytogenetic differentiation between TC and AC. These additional changes might be responsible for the more aggressive behavior of AC. Three cases of LCNEC, the first to be analyzed by comparative genomic hybridization, exhibited similar complex abnormal patterns (4q-, 5q-, 10q-, 13q-, 15q-) to those of SCLC. Although neuroendocrine tumors of the lung share common phenotypic features, suggesting a genotypic relationship, they differ remarkably in their cytogenetic characteristics, highlighting an early fundamental molecular divergence during the development of these tumors.

Apoptosis and expression of bcl-2 protein are inverse factors influencing tumour cell turnover in primary carcinoid tumours of the lung

AIMS

This study evaluates potential regulating factors in primary pulmonary carcinoid tumours, 16 typical and four atypical samples, with special emphasis on apoptosis and the bcl-2 gene family. Furthermore, p53-related oncogenes were analysed in a search for associated biological parameters.

METHODS AND RESULTS

The in-situ end-labelling technique (ISEL) was used to determine apoptotic cells, in addition to immunohistochemical methods, which were used to investigate the expression of the Ki67 antigen (avidinbiotin complex (ABC) method) and bcl-2, bcl-x, p53, p21/waf1, p27 and mdm-2 proteins (catalysed reporter deposition (CARD) technique). The incidence of apoptotic tumour cells was significantly enhanced in typical carcinoids. The bcl-2 protein was expressed to a higher degree in atypical carcinoids, which displayed a higher proliferative capacity as well. In contrast, bcl-x was observed predominantly in so-called typical carcinoids. The tumour cell turnover index was the most distinguishing parameter between both entities. All carcinoid tumours failed to show a staining for p53, p21/waf. p27 and mdm-2 proteins.

CONCLUSIONS

The different biological behaviour of the carcinoid tumours under study seems to be influenced by the bcl-2 gene family preventing programmed cell death. We speculate that this results in a more aggressive course in atypical carcinoid tumours.

Expression of the alpha- and beta-subunits of human chorionic gonadotropin by subsets of parathyroid cells in states of hyperparathyroidism

The alpha-subunit of human chorionic gonadotropin (hCG-alpha) has previously been found to be expressed in hyperplasias and tumours of numerous endocrine tissues including all those involved in MEN-I syndrome except the parathyroid glands. In the present immunohistochemical investigation of 86 patients with various states of hyperparathyroidism, expression of hCG-alpha by subsets of parathyroid cells was shown in 46 cases (54 per cent) including all states of hyperparathyroidism investigated: primary adenoma (n = 34, 44 per cent); uraemic secondary hyperplasia (n = 34, 53 per cent); MEN-I (n = 13, 77 per cent); MEN-II (n = 2, 100 per cent); and parathyroid carcinoma (n = 3, 100 per cent). Although the number of parathyroid cells expressing hCG-alpha was in general low, the occurrence of numerous immunoreactive cells appeared to be concentrated in primary adenoma and MEN-I (20 and 33 per cent of positive cases, respectively). No expression was found in ten normal control glands, except for very rare cells in one case. Expression of hCG-alpha was in part associated with that of hCG-beta, which appeared to be more commonly expressed than hCG-alpha in cases of secondary hyperparathyroidism. In separate experiments, Bouin fixation was found to preserve the immunoreactivity of hCG-alpha and hCG-beta better than the formalin fixation used in this study, suggesting that the figures may be underestimates. These immunohistochemical results are in agreement with a previous biochemical study showing hCG-alpha and hCG-beta in extracts of parathyroid tumours and extend to the parathyroid glands the otherwise ubiquitous finding of hCG-alpha expression in MEN-I-related neoplasms.

Value of Ki-67 immunostaining in preoperative biopsies of carcinomas of the lung

In lung carcinomas, the proliferative activity, as detected by Ki-67 antigen immunostaining of surgical specimens, is a valuable factor predicting clinical evolution and response to treatment. We investigated whether bronchial endoscopic and fine-needle aspiration (FNA) biopsies of lung carcinoma can provide a reliable estimation of the tumor proliferative fraction (TPF). In 66 resectable lung carcinomas, sections of preoperative bronchial or FNA biopsies and the corresponding surgical specimens were stained in parallel for Ki-67 using MIB-1 monoclonal. The mean TPF was 44.7% in the surgical specimens, 40.3% in bronchial biopsies, and 26.3% in FNAs. When the scores of biopsy and resected specimen of each individual tumor were compared, a significant correlation between the TPFs of preoperative and postoperative specimens was found (r = .79). In both biopsy and surgical specimens, a high TPF was associated with squamous cell carcinoma histological type and high-grade (poorly differentiated) tumors. In addition, a significantly (P < .05) lower disease-free interval was found in patients affected by highly proliferating tumors (irrespective of the tumor stage). We conclude that the proliferative activity of lung cancer can be reliably assessed in bronchial or FNA biopsies. This information could help to select chemotherapy protocols in nonresectable lung carcinomas.

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.

Endocrinopathy and ectopic hormones in malignancy

This article reports progress in the field of endocrinopathies and focuses on the molecular aspects of these diseases. Implications for genetics and metabolic study are presented. Although limitations of earlier approaches are confirmed, progress is noted, particularly with regard to the contribution of octreotide scintigraphy. Integrated with the evolving applications of molecular insights, significant clinical progress has been recorded.

DNA cytophotometry and prognosis in typical and atypical bronchopulmonary carcinoids. A clinicomorphologic study of 100 neuroendocrine lung tumors

Surgical material obtained from 100 patients with typical carcinoids (TC) and atypical carcinoids (AC) of the lung (including 100 primary, four residual tumors, and four lymph node or distant metastases) was investigated by conventional histology and scanning DNA cytophotometry. Of the 60 TC (96%), 58 exhibited euploid DNA histograms compared with only 20 (50%) of the 40 AC. The morphologic findings were related to the patients' survival (median observation period, 9 years). Statistical analyses disclosed the histologic type of disease (TC versus AC) and the DNA content of tumors (euploid versus aneuploid) to affect prognosis significantly (p < 0.001). Deaths resulting from tumor were exclusively observed among patients with atypical (eight of 40) or DNA aneuploid carcinoids (eight of 22). Six patients were alive with persistent tumor manifestations 3 to 20 years after initial diagnosis, four with DNA diploid primary carcinoids. The presence of lymph node metastases alone was not associated with poor prognosis as long as the primary tumor or the related metastases showed a diploid DNA content. DNA cytophotometry thus might be regarded as an adjunctive prognostic criterion in individual carcinoid cases.

Secretoneurin in bronchopulmonary carcinoids--immunohistochemical comparison with chromogranins A and B and secretogranin II

Ninety-nine classical and 11 atypical bronchopulmonary carcinoids were investigated immunohistochemically with an antibody against secretoneurin, a peptide proteolytically processed from secretogranin II (chromogranin C), as well as antibodies against chromogranin A and B and secretogranin II. Secretoneurin was immunolocalized in 86 tumours (78 classical and eight atypical carcinoids); secretogranin II was found in the same tumours in a similar distribution, whereas chromogranin A was present in all 100 and chromogranin B in 106 tumours investigated. Bronchopulmonary carcinoids are usually not associated with clinically or biochemically distinct syndromes. Although we found bronchial carcinoids with different immunohistochemical chromogranins/secretogranin patterns, no correlation with the biological behaviour of these tumours could be demonstrated.

Immunohistochemical demonstration of chromogranin A, chromogranin B, and secretoneurin in primary non-small-cell carcinomas of the lung

Fifty-three primary non-small-cell lung carcinomas (NSCLC) were immunohistochemically investigated with antibodies against chromogranin A, chromogranin B, and ecretoneurin. All 3 peptides were focally immunolocalized in 3 of 25 adenocarcinomas and in 2 of 6 large-cell anaplastic carcinomas in more than 20% of tumor cells. Two of 15 squamous-cell carcinomas showed chromogranin B reactivity in more than 20% of tumor cells. Neuroendocrine (NE) differentiation was also demonstrated in lymphnode metastases of large-cell anaplastic carcinomas, in 1 adenocarcinoma, and in 1 squamous-cell carcinoma, with NE differentiation of the respective primary tumors. All tumors with NE differentiation exhibited (large cell) anaplastic tumor areas. We conclude that NE differentiation should be immunohistochemically proven or excluded, particularly in NSCLC with anaplastic components. Chromogranin B and secretoneurin are proposed as useful additional neuroendocrine markers for demonstration of NE differentiation in lung carcinomas.

Serological tumor markers for small cell lung cancer and their therapeutic implications

Serological tumor markers may become widely used as inexpensive and non-invasive methods of cancer detection. Markers of current interest for small cell lung cancer (SCLC) comprise enzymes, peptides, proteins, and carbohydrates. None of the serological markers for SCLC have yet proven to be of diagnostic value and at present their use is limited to monitoring disease and indicating prognosis. However, whilst serological markers related to the metabolic state of SCLC cells, such as neuron-specific enolase, serum thymidine kinase and tissue polypeptide antigen, may only be used for monitoring patients and for estimating prognosis, the other serological markers under current investigation may be used to indicate new treatment forms. Several novel approaches, including interference in the autocrine growth-regulating loop of SCLC by either peptides or antibodies, have been tried, SCLC is a highly heterogeneous tumor with respect to antigen expression, regulation of growth, and differentiation state. It is therefore important that new interventions are directed against both antigen-positive and antigen-negative tumor cells. For instance, radioisotopes or enzymes coupled to antibodies may be effective by exerting toxicity at some distance from the target. Antigens expressed on SCLC cells, such as peptide receptors involved in growth regulation, carbohydrate antigens like Lewis antigens, carcinoembryonic antigen and the ganglioside fucosylGM1, provide potential targets for antibody-conjugated therapy.

Atypical carcinoid tumour of the lung: a study of 33 cases with prognostic features

Atypical carcinoids of the lung (well-differentiated neuroendocrine carcinomas) are rare tumours of uncertain prognosis. We have studied 33 cases--male to female ratio 2:1, age range 22-75 years, mean 55 years, 80% smokers, 15 peripheral and 18 central, tumour size 1.2-9.5 cm. Microscopically they had a nesting/insular, trabecular or lobular pattern. Nuclear morphology was variable, round cells, large cells and spindle cells being identified with small cell areas in five tumours. Mitotic activity varied from 4 to 80 per 1.52 mm2. Areas of necrosis were seen in all tumours. All 33 tumours were cytokeratin positive (AE1/AE3 and CAM5.2), 32 were positive for neuron-specific enolase, synaptophysin and chromogranin A. Electronmicroscopy showed dense core granules in 29 available cases. Nineteen cases were stage I, nine stage II, four stage III and one stage IV. Follow-up information was available for 22 cases. Size, location, stage and large cell/small cell morphology were important prognostic indicators. Large tumour size, large cell or mixed large cell/small cell morphology, peripheral localization and advanced stage were adverse prognostic indicators. Mitotic activity and the presence of necrosis did not appear to influence stage or behaviour.

Tumors of the endocrine/neuroendocrine system: an overview

For the sake of discussion, the markedly diversified tumors of the endocrine/neuroendocrine system are classified as those originating in classic epithelial endocrine organs (eg, adrenal cortical adenomas), from the diffuse endocrine cells (eg, jejunal carcinoid tumors), or from clusters of these cells (eg, islet cell tumors); and those arising from neurosecretory neurons (eg, neuroblastoma) or paraganglia (eg, carotid body tumor). Although traditional transmission electron microscopy is useful for identifying neurosecretory or endosecretory granules as such, with few exceptions (eg, insulin-containing granules with a complex paracrystalline core) it is not possible to ascribe a granule type (size, shape, or ultrastructure) to a distinct nosologic entity or secretory product because of their overlapping fine structures in different cell types. Immunoelectron microscopy methods utilizing colloidal gold-labeled secondary antibodies can be used to localize virtually any antigen (peptide or neuroamine) to a specific neurosecretory or endosecretory granule or other cell structure. General endocrine/neuroendocrine cell markers such as neuron-specific enolase, the chromogranins, and synaptophysin are useful in identifying neuroendocrine differentiation in a neoplasm using routine immunohistochemical procedures. The current relevance of the APUD concept of Pearse as well as the biologic importance of endocrine/neuroendocrine secretory products such as bombesin and insulinlike growth factors also are discussed.

Three subtypes of gastric argyrophil carcinoid and the gastric neuroendocrine carcinoma: a clinicopathologic study

BACKGROUND

Enterochromaffinlike (ECL) cell carcinoids recently observed in rats stimulated new interest in gastric endocrine tumors arising in humans.

METHODS

Paraffin-embedded sections of 55 endocrine tumor cases were stained with H&E, mucin tests were performed, and immunoperoxidase was used for detecting endocrine markers; 23 cases were also investigated ultrastructurally.

RESULTS

Forty-five argyrophil carcinoids, 9 neuroendocrine carcinomas, and 1 gastrinoma were identified. Three clinicopathologic subtypes of carcinoids were characterized: (1) twenty-eight cases, none metastatic, arose in a background of body-fundus atrophic gastritis and hypergastrinemia; (2) seven cases, 2 locally metastatic, were associated with hypertrophic gastropathy and hypergastrinemia due to multiple endocrine neoplasia/Zollinger-Ellison syndrome; and (3) ten were sporadic cases, 7 of which were deeply invasive, 6 metastatic, and 5 histologically atypical. All carcinoids showed histochemical and ultrastructural patterns of ECL cells. The 9 neuroendocrine carcinomas, all deeply invasive and metastatic, were composed of anaplastic, small- to intermediate-sized cells with high mitotic index and focal necrosis.

CONCLUSIONS

Gastrin-promoted carcinoids represent a benign or low grade tumor disease, whereas sporadic carcinoids and neuroendocrine carcinomas are life-threatening neoplasms, independent of gastrin promotion.