Well-Differentiated Neuroendocrine Carcinoma of the Lung: A Clinicopathologic and Ultrastructural Study of 10 Cases

The clinico-pathologic characteristics of 10 resected pulmonary tumors, which proved to be well-differentiated neuroendocrine carcinomas (WDNC) on the basis of light microscopic, immunocytochemical, ultrastructural and immunoelectron microscopic investigations, were evaluated. The tumors showed a wide spectrum of histologic features that could be referred to three basic patterns: 1) a carcinoid-like pattern; 2) an organoid pattern characterized by palisading cells at the edge of cellular areas, and 3) a prevalent adenocarcinoma-like pattern. The second pattern was the most distinct even though it often mimicked the small cell/large cell subtype of small cell carcinoma (SCC) owing to its association with marked atypia and poor differentiation. All but one of the patients were males and smokers. The mean age was 58 years. Half of the tumors were centrally located including those showing the adenocarcinoma-like pattern. Disease-free and overall survival and type of tumor dissemination in four patients were similar to those of SCC. Five evaluable patients were alive and disease-free after a mean follow-up of 74 months. Two of these were initially diagnosed as SCC. We conclude that, because of its impact on prognosis, the diagnosis of WDNC appears to be relevant although other factors able to adversely affect the clinical course remain undefined.

Multiple Gastric Carcinoids and Pernicious Anemia: Report of a Case

A case of pernicious anemia associated with multiple gastric carcinoids is reported. The neoplastic growth was composed of enterochromaffin-like (ECL) cells, and ECL cell hyperplasia was observed also in hyperplastic polyps, inside the fundic glands and in small nests lying in the lamina propria (microcarcinoidosis). The possible relation between pernicious anemia and ECL cell hyperplasia is discussed.

Strumal Carcinoid of the Ovary: An Immunohistochemical and Electron Microscopic Study

A case of strumal carcinoid of the ovary is reported. The follicles contained T4-immunoreactive substance, whereas the carcinoid component of the tumor had a trabecular structure and showed argyrophilic elements. Pancreatic-polypeptide and enteroglucagon were localized in these cells by an immunocytochemical method. The same cells displayed small electrondense endocrine-like granules. A common precursor for the thyroid and carcinoid components is postulated.

[Morphological features of pulmonary and thymic carcinoid tumor]

Morphological features of atypical and typical subtypes of pulmonary and thymic carcinoid tumors have been studied by pathohistological, immunohistochemical and electron-microscopic methods. There are the main principles of differential diagnostics in the article.

Ghrelin-producing well-differentiated neuroendocrine tumor (carcinoid) of tailgut cyst. Morphological, immunohistochemical, ultrastructural, and RT-PCR study of a case and review of the literature

Well-differentiated neuroendocrine tumors (carcinoids) arising in the presacral space are rare neoplasms that can arise in association with either sacrococcygeal teratomas or tailgut cysts. Although tumors arising in tailgut cysts are more frequent than those associated with teratomas, they are still very rare, and only 13 cases have been reported in the literature. We describe the first case of a carcinoid composed of ghrelin-producing cells arising in a tailgut cyst. Ghrelin production was demonstrated using immunohistochemistry, electron microscopy, and reverse transcription-polymerase chain reaction methods. A 73-year-old woman with back and pelvic pain was found to have a presacral mass histologically diagnosed, on needle biopsy, as a well-differentiated neuroendocrine tumor. Workup did not show another primary tumor or metastatic disease. The patient underwent laparoscopic resection of the mass, and the pathological diagnosis of the surgical specimen was of a tailgut cyst-associated carcinoid composed of ghrelin-producing cells. In addition, we have accurately reviewed the literature on presacral carcinoids, associated or unassociated with tailgut cysts, to give the reader a comprehensive overview of these very rare tumor types.

Carcinoid tumor of the middle ear

The patient was a 32 year-old man who was first seen in 2003 for 2 years hearing loss. On otoscopic examination, a whitish mass could be observed through the intact tympanic membrane. High resolution computed tomography showed a tumor like lesion in the middle ear with no evidence of bone destruction. A tympanomastoidectomy was performed. Light microscopy showed fragments of cellular tissue in which both glandular and trabecular growth pattern could be identified Immunohistochemical examinations showed positive staining of the tumor cells for cytokeratin and chromogranin. The diagnosis of carcinoid tumor should be considered in all cases of adenomatous neoplasms of the middle ear and mastoid. Conservative surgical excision is the treatment of choice, and local recurrence following complete excision is uncommon.

Frizzled-7 dictates three-dimensional organization of colorectal cancer cell carcinoids

Progression of colorectal cancer (CRC) involves spatial and temporal occurrences of epithelial-mesenchymal transition (EMT), whereby tumour cells acquire a more invasive and metastatic phenotype. Subsequently, the disseminated mesenchymal tumour cells must undergo a reverse transition (mesenchymal-epithelial transition, MET) at the site of metastases, as most metastases recapitulate the pathology of their corresponding primary tumours. Importantly, initiation of tumour growth at the secondary site is the rate-limiting step in metastasis. However, investigation of this dynamic reversible EMT and MET that underpins CRC morphogenesis has been hindered by a lack of suitable in vitro models. To this end, we have established a unique in vitro model of CRC morphogenesis, which we term LIM1863-Mph (morphogenetic). LIM1863-Mph cells spontaneously undergo cyclic transitions between two-dimensional monolayer (migratory, mesenchymal) and three-dimensional sphere (carcinoid, epithelial) states. Using RNAi, we demonstrate that FZD7 is necessary for MET of the monolayer cells as loss of FZD7 results in the persistence of a mesenchymal state (increased SNAI2/decreased E-cadherin). Moreover, FZD7 is also required for migration of the LIM1863-Mph monolayer cells. During development, FZD7 orchestrates either migratory or epithelialization events depending on the context. Our findings strongly implicate similar functional diversity for FZD7 during CRC morphogenesis.

Ultrastructure and chromogranin A immunogold labelling of ECL cell carcinoids

Poorly differentiated neuroendocrine cells can be difficult to recognise. Sensitive methods are needed to label cells that have lost their ultrastructural features and have reduced concentrations of neuroendocrine markers. In gastric neoplasms, enterochromaffin-like cells might dedifferentiate and lose their characteristic granules and secretory vesicles, making detection of such cells increasingly difficult. However, chromogranin A (CgA) immunogold labelling could provide sensitive and specific detection of gastric neuroendocrine cells. We present ultrastructural findings, CgA immunogold labelling as well as conventional immunohistochemical findings of two human enterochromaffin-like cell carcinoids. Electron-dense granules of poorly differentiated cells were less intensely labelled than granules in well-differentiated cells. Granules with atypical shape as well as punctuate granules previously found in neuroendocrine neoplasms were also CgA labelled. The CgA labelling efficacy after antigen retrieval in an alkaline solution was higher after heating in an autoclave at 135 degrees C compared to a microwave at 100 degrees C for both granules and secretory vesicles without significant deterioration of the ultrastructure. In conclusion, the use of CgA immunogold labelling could ensure a specific classification of cells with neuroendocrine granules and be a supplement to immunohistochemical examination of poorly differentiated tumours.

A new simplified catalyzed signal amplification system for minimizing non-specific staining in tissues with supersensitive immunohistochemistry

We investigated non-specific staining in a catalyzed reporter deposition (CARD) reaction and improved its blocking methods in supersensitive immunohistochemistry, based on our simplified catalyzed signal amplification (CSA) system (Hasui et al. 2002). In the CARD reaction using biotinyl tyramide, non-specific staining could be reduced by pretreatment with a casein solution or 3% bovine serum albumin (BSA)-phosphate buffer saline (PBS) with 0.1% Tween 20. In the CARD reaction using FITC-labeled tyramide, non-specific staining could be blocked by pretreatment with 0.3% BSA-PBS with 0.1% Tween 20 or 3% polyethylene glycol-PBS with 01% Tween 20. Thus, our new simplified CSA system features: 1) destruction of the endogenous peroxidase activity; 2) blocking of the nonspecific reaction of the primary antibody; 3) a primary antibody reaction; 4) blocking of the non-specific reaction of the polymer reagent by casein treatment; 5) a polymer reaction; 6) blocking of the non-specific reaction of CARD reaction by casein treatment; 7) a CARD reaction; and 8) detection of deposited tyramide. This new system proved useful for detecting an extremely low amount of antigen in the endogenous biotin-rich tissues such as the gastrointestinal tract and liver. By this method, the Ki67 antigen in the G1 phase cell cycle could be detected and a metabolic disorder of the Ki67 antigen was implicated in a carcinoid tumor in the stomach. We believe that this new simplified CSA system represents a new standard of supersensitive immunohistochemistry for use in light-microscopic investigation.

Expression of occludin in human rectal carcinoid tumours as a possible marker for glandular differentiation

AIMS

To examine whether or not the tight junction-associated transmembrane protein occludin is expressed in rosette or gland-like structures in human rectal carcinoid tumours. The tight junction is crucial for the formation and maintenance of organized tubular structures in glandular epithelia. Previous studies have reported the presence of glandular structures in carcinoid tumours, though they are not believed to arise from glandular epithelium.

METHODS AND RESULTS

The expression profiles of occludin in 40 carcinoid tumours were examined immunohistochemically, using an anti-occludin monoclonal antibody. In eight (20%) samples of typical carcinoid tumours, a small number of rosette-like tubular structures outlined by occludin were detected.

CONCLUSIONS

Tight junction-associated molecules, including occludin, are thought to be one of the most characteristic structural markers of polarized glandular structures. The results of the present study provide supportive evidence that carcinoid tumour cells are capable of glandular differentiation.

Raf-1 activation suppresses neuroendocrine marker and hormone levels in human gastrointestinal carcinoid cells

Gastrointestinal carcinoid cells secrete multiple neuroendocrine markers and hormones including 5-HT and chromogranin A. The intracellular signaling pathways that regulate production of bioactive molecules are not completely understood. Our aim was to determine whether activation of the raf-1/MEK/MAPK signal transduction pathway in carcinoid cells could modulate production of neuroendocrine markers and hormones. Human pancreatic carcinoid cells (BON) were stably transduced with an estrogen-inducible raf-1 construct creating BON-raf cells. Activation of raf-1 in BON-raf cells led to a marked induction of phosphorylated MEK and ERK1/2 within 48 h. Importantly, raf-1 activation resulted in morphological changes accompanied by a marked decrease in neuroendocrine secretory granules by electronmicroscopy. Moreover, induction of raf-1 in BON-raf cells led to significant reductions in 5-HT, chromogranin A, and synaptophysin levels. Furthermore, treatment of BON-raf cells with MEK inhibitors PD-98059 and U-0126 blocked raf-1-mediated morphological changes and hormone suppression but not ERK1/2 phosphorylation. These results show that raf-1 induction suppresses neuroendocrine marker and hormone production in human gastrointestinal carcinoid cells via a pathway dependent on MEK activation.

A carcinoid tumor in the gallbladder of a dog

A cholecystectomy was performed on a 10-year-old spayed female mixed-breed dog with chronic weight loss, persistently increased liver enzyme activities, and cholecystomegaly identified by ultrasonographic examination. A subsequent diagnosis of a biliary carcinoid was made based on a neuroendocrine-type histologic pattern, cytoplasmic argyrophilia by Grimelius staining, immunopositivity for chromogranin A, and the ultrastructural finding of cytoplasmic secretory granules in neoplastic cells. Extrahepatic biliary carcinoid tumors are rare tumors of humans and have not been documented in domestic animals.

A unique early gastric tubular adenocarcinoma arising from a pre-existent carcinoid tumor in a patient with a more than 20-year history of type A gastritis: an immunohistochemical and ultrastructural study

A unique early gastric tubular adenocarcinoma developed from a pre-existent carcinoid tumor in a patient with a more than 20-year history of type A gastritis, multiple endocrine cell micronests, hypergastrinemia, and a high level of serum antiparietal cell autoantibody. The patient was a 60-year-old Japanese man. The background gastric mucosa around the tumor showed marked atrophy with intestinal metaplasia, in which endocrine cell micronests were frequently observed, and was consistent with type A gastritis. The mass was composed of both adenocarcinoma and carcinoid tumor. The adenocarcinoma was restricted to the lamina mucosa and submucosal area, and constituted a minor component of the tumor mass. The carcinoid tumor was the dominant constituent of the tumor, that invaded continuously the subserosa and muscularis propria. Based on this examination together with the detailed immunohistochemical and ultrastructural studies, the adenocarcinoma was presumed to have developed from the pre-existent carcinoid tumor. Ultrastructurally there were no amphicrine cells in the tumor, containing both endocrine granules and mucin droplets.

Bronchial carcinoid tumor with crystalloid cytoplasmic inclusions

We report a bronchial carcinoid tumor with distinctive, cytoplasmic, rod-shaped crystalloid inclusions that were visible by light microscopy. These cytoplasmic structures were immunoreactive with antibodies against chromogranin A and synaptophysin in paraffin-embedded tissue. Ultrastructural studies showed them to be paracrystalline in nature and located within lysosomes. This case highlights an interesting, and potentially confusing, histologic manifestation in an otherwise typical bronchial carcinoid tumor.

Statistical analysis of endocrine granule size in gastrointestinal carcinoids

Regarding the size of endocrine granules in endocrine neoplasms including carcinoids, most authors have reported only the range of granule diameters, and few studies on detailed morphometry of granule sizes have been documented. The statistically comparative study of endocrine granule sizes among such neoplasms, therefore, presented many difficulties. In the present study, we investigated more detailed findings on the endocrine granule sizes by using statistical analyses of diameters of numerous (n > 200 from each tumor) endocrine granules measured randomly throughout the cytoplasm in 18 gastrointestinal carcinoids. The measured data were analyzed statistically to obtain the histogram, distribution curve, mean value, and standard deviation of granule diameters in each carcinoid. It was disclosed by the analyses that all rectal carcinoids possessed uniformly small endocrine granules in contrast to gastric and duodenal carcinoids, which showed wide distribution of granule sizes, having significantly greater diameters than those in the rectal carcinoid series. The correlation between endocrine granule sizes and producing hormone(s) was, however, not confirmed.

Goblet cell carcinoids of the appendix: immunophenotype and ultrastructural study

BACKGROUND

Goblet cell carcinoids of the appendix are rare neoplasms with uncertain biological behavior.

OBJECTIVE

The aims of our study were to evaluate the immunophenotype of this neoplasm with cell cycle/cell proliferation markers and to understand their histogenesis with ultrastructural analysis using conventional carcinoids as a frame of reference.

METHODS

Clinical data and archival pathologic material of all goblet cell carcinoids of the appendix recorded by the Saskatchewan Cancer Registry between 1970 and 1998 were reviewed and evaluated by light microscopy, histochemistry, immunohistochemistry, and electron microscopy.

RESULTS

Seven cases of goblet cell carcinoids were identified among 110 cases of conventional carcinoids of the appendix. Histopathology revealed widespread infiltration of the periappendiceal fat in all cases, with extensive perineural invasion. The cells stained strongly positive for mucicarmine, periodic acid-Schiff, periodic acid-Schiff diastase, Alcian blue, cytokeratin, and carcinoembryonic antigen. Most cases were positive for synaptophysin. Increased expression of cell proliferation markers and cell cycle markers was observed. Expression of p53 was strong in one case. Electron microscopy demonstrated the presence of mucinous vacuoles of varying sizes and occasional membrane-bound neuroendocrine granules.

CONCLUSIONS

Goblet cell carcinoids of the appendix arise from a pluripotent cell with divergent neuroendocrine and mucinous differentiation. These neoplasms are widely invasive; they demonstrate a high cellular proliferation rate and dysregulation of the cell cycle with up-regulation of cyclin D1 and p21, and down-regulation of p16. Complete removal of the tumor is recommended because of the unpredictable biological behavior of this tumor, which includes delayed local recurrences and lung metastases.

Epithelial tumors of the lung

Our knowledge and understanding of bronchopulmonary tract tumors have grown considerably; modern pathology enables the phenotyping of many tumors with increasingly improving techniques and tools and, arguably, improving criteria. By the same token, at least some of the new data may not be readily grafted onto traditional classification schemes. Some traditional designations will be dropped and replaced. And, although it has been overenthusiastically argued that molecular classifications may be attained, that ideal might not be truly an improvement. For classifications to be useful, they should be relatively simple, easily reproducible, and clinically significant. Still, modern marker pathology has revealed new vistas for the evaluation, diagnosis, and therapy of at least some tumors. These developments merit optimism but also caution from clinicians and pathologists.

Gastric carcinoid with histamine production, histamine transporter and expression of somatostatin receptors

A case of sporadic, histamine-producing gastric carcinoid with liver metastases is reported. The patient was treated with somatostatin analogue (octreotide) combined with cortisone and blockade of histamine receptors prior to surgery, which included subtotal gastrectomy, excision of lymph node metastases and superficial liver metastases. Residual liver metastases were injected with ethanol. These interventions markedly reduced the urinary excretion of the main histamine metabolite (MelmAA). Eighteen months later combined immuno- and chemotherapy was initiated due to tumour progression and recurrent hormonal symptoms with good clinical results over 12 months. Scintigraphy, using 111In-DTPA-D-Phe1-octreotide, visualized somatostatin receptors (sstr) in primary tumour, lymph node metastases and liver metastases. The tissue/blood 111In concentration ratios of tumour biopsies were very high. Northern analyses confirmed expression of all subtypes of sstr1-5. Immunocytochemically, tumour cells were strongly positive for chromogranin A, histamine and vesicular monoamine transporter (VMAT) 2 (histamine transporter), but negative for VMAT 1, suggesting an origin from gastric enterochromaffin-like cells. In primary tumour cell cultures, histamine, 5-HTP and 5-HIAA, but not 5-HT, could be detected in conditioned culture medium, indicating a defective decarboxylation of the tryptamine precursor. This rare case of histamine-producing gastric carcinoid demonstrates that excellent symptom relief can be achieved despite disseminated disease, if active, multimodal treatment strategy is instituted. The presence of high numbers of sstr in tumour tissue also raises the possibility of receptor-guided radiotherapy.

Nuclear localization of 111In after intravenous injection of [111In-DTPA-D-Phe1]-octreotide in patients with neuroendocrine tumors

Treatment with tumor-targeting substances is currently being evaluated in clinical trials. For patients with neuroendocrine tumors expressing somatostatin receptors, the 111In-labeled somatostatin analog [diethylenetriaminepentaacetic acid (DTPA)-DPhe1]-octreotide has been used with promising results. To further investigate the clinical effect of the injected conjugate, we analyzed the cellular distribution of 111In by ultrastructural autoradiography.

METHODS

Seven patients with somatostatin receptor-expressing midgut carcinoid tumors scheduled for abdominal surgery were investigated by somatostatin receptor scintigraphy. During operation, tumor tissue samples and samples of normal intestine were collected, fixed, and processed for electron microscopy. A thin layer of film emulsion was applied on sections and after the exposure film was developed. The cellular distribution of silver precipitations indicating the presence of isotope was evaluated.

RESULTS

Cell surface receptor binding and internalization of [111In-DTPA-D-Phe1]-octreotide in the tumor cells was easily revealed by silver precipitations in the film. Multiple silver grains were seen at the plasma membrane, in the cytoplasmic area among secretory granules and vesicular compartments, and in the perinuclear area. Silver grains were also regularly located in the nucleus. For all patients, the silver precipitation patterns from 111In decay were identical in all examined cells from removed tumors, and in most cells 111In could be seen in the nucleus. The specificity of the silver reaction products is supported by the observation that enterocytes in intestinal tissue specimens from near the tumor did not show any silver grains and no background labeling was seen in the plastic.

CONCLUSION

After internalization through the somatostatin receptor system, 111In is translocated to the perinuclear area and into the nucleus. Whether the nuclide is still conjugated to the intact somatostatin analog or to part of it cannot be evaluated in this study. Despite the short irradiation range of 111In, the nuclear localization can explain its clinical effectiveness. The results from this study suggest that [111In-DTPA-D-Phe1]-octreotide may act as a powerful tumor cell-targeting substance.

Amphicrine tumor

The term amphicrine refers to cells, and tumors, which show both exocrine and endocrine features. Author s aim was to analyse the characteristics of these neoplasms. 40 suspicious cases were reviewed. Mucin-stains (PAS, diastase-PAS, Stains-all, Alcian-blue), immunohistochemistry (antibodies against Neuron-Specific Enolase (NSE), and Chromogranin A (CGA), and electronmicroscopic studies were performed to demonstrate exocrine and/or endocrine features of the tumor cells. By means of these methods, 16 cases turned out to be amphicrine tumors. Among them, there were 4 sinonasal, 1 bronchial, 1 mediastinal, 8 gastrointestinal and 2 suprarenal gland neoplasms. In connection to the subject, a brief review is given of amphicrine tumor, regarding its etiological and pathological aspects. These tumors form a distinct clinicopathological entity and should be separated from both neuroendocrine tumors and adenocarcinomas.

[Electron microscope study of lung carcinoid]

123 lung carcinoids were studied, 32 of them electron-microscopically. Ultrastructural features were evaluated with the use of multivariate analysis. The most informative ultrastructural features were the following: correlation between differentiated and undifferentiated cells, the number of cytoplasm organoids including endocrine granules, degree of nuclei polymorphism and their size, specialized contacts, mitoses. Up to 18% of carcinoids, on the average, need ultrastructural verification of the anaplasia degree, this percentage increasing to 27.2% in atypical carcinoids. The above ultrastructural criteria allow to specify malignant potential of carcinoids, facilitate differential diagnosis and make their prognosis.

Motilin-producing liver and bone metastases evidenced 14 years after resection of a rectal polyp

A 62-year-old man with a history of a resected rectal polyp was diagnosed 14 years later with right liver and multiple bone metastases. The liver biopsy showed a malignant epithelial tumor that was positive for neuron-specific enolase immunostaining and negative for chromogranin. Electron microscopy was characteristic of that for an endocrine tumor. Most circulating hormonal peptide levels were within normal ranges and only motilin level was elevated. On the right hepatectomy, the three large metastases had a histologic picture suggestive of an endocrine tumor. Immunohistochemistry revealed in some areas numerous tumor cells expressing motilin, and a few cells were strongly positive for pancreatic polypeptide and somatostatin. The retrospective analysis of the rectal polyp showed a similar histology and immunohistochemical profile, indicating that this lesion was the primary tumor. Motilin-positive cells from one of the hepatic lesions were identified on semithin sections and further processed for electron microscopy. Neurosecretory granules were numerous in all cells. Immunoelectron localization enabled us to characterize the motilin-containing neurosecretory granules, which had a mean diameter of 168.3x38.1 nm. Although not all tumor cells were motilin-positive, a diagnosis of motilinoma for the rectal polyp and its hepatic and bone metastases was proposed.

A classification of problems regarding gut endocrinomas (carcinoids and relevant neoplasms)

In the field of gut endocrinomas (carcinoids and relevant neoplasms), several classifications have been internationally accepted and utilized at varying frequency. The basis of the concepts regarding gut endocrinomas from which these classifications have been proposed were drawn from the different aspects. These included embryology, histologic growth patterns, histochemistry including silver impregnations, electron microscopic morphology of endocrine secretory granules, endocrine cell types and histologic morphology along with functional characteristics, supplemented by immunohistochemical features. Due to continuous progress being made in this particular field of research and the many new discoveries made by pioneering investigators, the concepts of gut endocrinomas have been modified and revised during such long history of the research activities. This study aims to re-evaluate these classifications in relation to the concepts of gut endocrinomas, and to select and supply rearranged classifications that may be easily utilized for practical purposes. This study also proposes a comprehensive overview of histogenesis in the gut endocrinoma group. This consists of typical carcinoids and their atypical variants taken in relation to the carcinomatous group including ordinary carcinomas and their variants with endocrine elements. Special emphasis is given to the point that there is a gradual transition, one without a definite boundary between these tumors.

A primary hepatic carcinoid tumor: evaluation by computed tomography and magnetic resonance imaging

A case of primary hepatic carcinoid tumor is reported. A 40-year-old woman was admitted to our hospital because of an epigastric mass. Ultrasonography demonstrated a heterogeneous, hyperechoic mass with hypoechoic area in the left lobe of the liver. CT showed a hypodense lesion with more hypodense areas. Enhanced CT showed slight retention of contrast medium and a low density area that suggested necrosis in the tumor. The mass appeared as a heterogeneous area of low signal intensity with sharp margin on T1-weighted MRI. T2-weighted MRI revealed a high intensity mass with higher intensity foci. Left lateral segmental hepatic resection was performed. Immunohistochemical and electron microscopic studies revealed the carcinoid tumor. Postoperatively, careful, intensive search revealed no other primary source of the tumor. The higher intensity foci were microscopically identified as intratumoral hemorrhage, corresponding to hemorrhagic areas on the cut surface. Therefore, T2-weighted MRI might reflect the pathological characteristics of the tumor.

Diagnostic usefulness of sustentacular cells in paragangliomas: immunocytochemical and ultrastructural investigation

Neuroendocrine tumors may derive either from neuroectoderm or endoderm. Both may present with a similar histologic pattern known as "Zellballen" regardless of their histogenetic origin, making it difficult to separate the two different histogenetic entities in certain cases. To evaluate the usefulness of sustentacular cells in the recognition of tumors of paraganglionic origin, the authors analyzed immunohistochemical and ultrastructural characteristics of 25 paragangliomas and 19 pulmonary and 10 small intestinal carcinoids. Sustentacular cells with characteristic dendritic features, strong immunoreactivity for S-100 protein, and agranular cytoplasm by electron microscopy were found consistently in the paragangliomas and not found in typical carcinoid tumors, except for four examples of spindle cell carcinoid of the lung. The presence of sustentacular cells in tumors with "Zellballen" pattern therefore denotes paraganglionic origin.

Primary hepatic carcinoid tumor with a paranuclear clear zone: a case report

Carcinoid tumors having distinct paranuclear clear zones seen on hematoxylin and eosin stain are rare and few cases have been reported in the literature. Furthermore, primary hepatic carcinoid tumor with a paranuclear clear zone is extremely rare. We recently experienced a case from a 48-year-old man who presented a large single mass, 12 cm in largest diameter, in the right lobe of the liver. Histologically, the tumor revealed characteristic organoid pattern with central hyaline degeneration. The tumor cells had a prominent paranuclear vacuolated dear zone. On immunohistochemistry, tumor cells were diffusely positive for synaptophysin and focally stained for chromogranin A. Ultrastructural examination revealed paranuclear aggregation of intermediate filaments and membrane-bound clear vesicles, which corresponded to the paranuclear vacuolated clear zone.

Presacral carcinoid tumors: report of three cases and review of the literature

The clinical, microscopic, immunohistochemical, and ultrastructural features of three carcinoid tumors of the presacral region are reviewed. All tumors occurred in young women and did not involve the rectum. The predominant microscopic pattern was trabecular. The differential diagnosis included paraganglioma and myxopapillary ependymoma. Immunohistochemically, neuroendocrine markers and low molecular weight cytokeratins were expressed in all cases. Neurosecretory granules were identified in the single case studied by electron microscopy. One case was associated with a tailgut cyst (retrorectal cystic hamartoma). Two patients were treated with complete local excision and are free of disease 3 and 4 years after surgery. One case metastasized to both breasts and recurred locally after an incomplete excision. This report expands the already long list of sites where carcinoid tumors can arise. The frequent association of these tumors with tailgut cysts and their histologic similarities to rectal carcinoid tumors suggest that the most likely derivation of presacral carcinoid tumors is from hindgut rests.

Carcinoids of the small intestine: a statistical evaluation of 1102 cases collected from the literature

A total of 1102 cases of jejunoileal carcinoids collected from 516 articles reported by over 35 countries or related areas were evaluated. Among these 1102 cases. 93 cases of Meckel's diverticular and 969 cases of remaining jejunoileal carcinoids could be effectively analyzed. Multiple clinicopathologic aspects were investigated including clinical manifestations, location, depth and size of the lesions related to metastases, immunohistochemistry, electron microscopy, carcinoid syndrome and serotonin activity. Jejunoileal carcinoids were characterized by a male preponderance with an age group older than that in the extraappendiceal gastrointestinal (GI) series. They also had a significantly aggressive malignant nature exhibiting a high metastasis rate particularly evident in small-size lesions with submucosal invasion. A high incidence of argentaffin cell type and carcinoid syndrome with high serotonin activity was also exhibited by jejunoileal carcinoids.

Thymic carcinoid. Report of a case with diagnosis by fine needle aspiration biopsy

BACKGROUND

Fine needle aspiration biopsy (FNAB) affords a less expensive, less morbid approach to masses within the complex anatomy of the mediastinum as opposed to surgical biopsy. Given the current state of computed tomography guidance and the available cell block preparations and ancillary studies, definitive diagnosis of mediastinal tumors is possible.

CASE

A 19-year-old male presented with weight loss and muscle weakness. Computed tomography revealed an anterior superior mediastinal mass with attachment to the posterior sternum and anterior aorta. FNAB yielded hyperchromatic cells with densely clumped chromatin and prominent nucleoli. These were present as single cells and clusters. Cell block preparations were studied with immunoperoxidase methods and were strongly positive for chromogranin and glucagon, supporting the diagnosis of carcinoid tumor. Surgical excision yielded a 7-cm, unencapsulated, red-brown tumor with medium-sized cells with oval to round nuclei, scant and granular cytoplasm and coarse "salt and pepper" chromatin with prominent nucleoli. The cells were arranged in islands and bands and were associated with prominent capillaries and dense, collagenous septae. Immunoperoxidase and electron microscopy demonstrated numerous intracytoplasmic, nonspecific neurosecretory granules and positivity for somatostatin, synaptophysin, cytokeratin and chromogranin.

CONCLUSION

FNAB affords an accurate and timely diagnosis of an anterior mediastinal tumor without the necessity for open biopsy and also offers accurate surgical planning and decreased morbidity.

Atypical carcinoid tumor of the larynx: an immunohistochemical, ultrastructural, and flow cytometric analysis

The clinicopathologic features, including a detailed immunohistochemical, ultrastructural, and flow cytometric analysis, are described in three cases of atypical carcinoid tumor of the larynx. All patients had metastatic disease within cervical lymph nodes at presentation and eventually developed distant metastases. Special stains revealed focal intracytoplasmic mucin accumulation, and immunohistochemistry showed the tumors to be positive for CAM 5.2, CEA, chromogranin A, and calcitonin. In two cases, double-staining techniques revealed occasional cells that stained for both mucin and chromogranin A. The histochemical and immunohistochemical findings in these two cases were confirmed at the ultrastructural level, with most tumor cells containing many neurosecretory granules. Smaller numbers of cells contained mucin vacuoles and, in occasional cells, both mucin and neuroendocrine granules were identified. The three tumors exhibited positive staining with D07 (anti-p53), and flow cytometric analysis revealed DNA aneuploidy and polyploidy. The double-staining and ultrastructural features indicate that laryngeal atypical carcinoid qualifies for the designation of true amphicrine carcinoma. Further study is necessary to determine whether mutation of the p53 gene is important in the evolution of laryngeal neuroendocrine tumors and whether DNA aneuploidy or polyploidy identifies a subset of these tumors with a poor prognosis.

Effects of gastrin on the histamine-secretory and proliferative activity of cultured carcinoid cells derived from the stomach of the rodent Mastomys natalensis

The effects of gastrin on the synthesis and release of histamine and on cellular proliferation were investigated in a homotransplantable carcinoid tumor implanted in the rodent Mastomys natalensis and in cultured cells derived from the tumor. The homotransplanted tumor was immunopositive for histamine, synaptophysin and protein gene product 9.5, and its cells contained numerous secretory granules that were visualized by electron microscopy. When carcinoid cells were cultured in a medium with a high concentration of gastrin-I (10(4) pg/mL) for 7 days, large electron-dense secretory granules were characteristically observed in the cytoplasm. By contrast, only a few such granules and numerous secondary lysosomes were seen in cells that had been cultured in the same medium without gastrin-I. A high concentration of gastrin-I (10(4) pg/mL) significantly increased the release of histamine into the culture medium from the carcinoid cells compared with the control (P < 0.05). Cellular proliferation, as determined by monitoring the incorporation of [methyl-3H]-thymidine into the carcinoid cells increased significantly at lower concentrations of gastrin-I (10(2) and 10(3) pg/mL), (P < 0.05). At higher concentrations (10(4) pg/mL or more), gastrin-I had no effect on proliferation. These findings indicate that gastrin stimulates the synthesis and release of histamine by carcinoid cells, as well as their proliferation.

Spindle-cell thymic carcinoid occurring in multiple endocrine neoplasia I: fine-needle aspiration findings in a case

Thymic carcinoid tumors are important to distinguish from thymomas because of their worse prognosis. These rare tumors occasionally occur in the setting of multiple endocrine neoplasia (MEN). A needle biopsy was performed on a 57-yr-old woman with MEN I and a newly-discovered anterior mediastinal mass. Aspiration smears were cellular and contained polygonal-to-spindled cells with high nucleocytoplasmic ratios and evenly-dispersed pattern. Occasional nuclear molding and rosette-like arrangements were present. A synaptophysin immunostain was positive on cell-block preparation. A diagnosis of thymic carcinoid was made. Subsequent excision of the mass confirmed the diagnosis of thymic carcinoid. Thymic carcinoids are cytologically similar to carcinoid tumors elsewhere. They should be distinguished from epithelial thymoma and substernal medullary carcinoma of the thyroid.

Sex steroid receptor expression in 'carcinoid' tumours of the breast

Nine 'carcinoids' of the breast (argyrophilic carcinomas) were examined for the presence of estrogen receptor (ER), progesterone receptor (PR), and androgen receptor (AR), using immunohistochemistry. The tumours were selected on the basis of their histo-morphological appearance and positive Grimelius stain. All cases were immunoreactive for neuron-specific enolase (NSE). In one case the tumour cells were intensely chromogranin A positive. All cases were ER positive, while 5 cases expressed AR and 5 cases PR. Immunostaining for ER and simultaneous demonstration of argyrophilia or chromogranin A expression in chromogranin A positive argyrophilic carcinoid tumour of the breast provided further evidence that neuroendocrine cells in breast tumours express sex steroid receptors. The similarity in sex steroid receptor expression pattern in 'carcinoids' of the breast and the more common categories of breast cancer suggests an identical responsiveness to endocrine therapy.

Immunoelectron microscopy for chromogranin A in small cell neuroendocrine carcinoma of lung

To see if immunoelectron microscopy can improve localization of neurosecretory granules, postembedding immunolabelling for chromogranin A was performed on 15 examples of small cell anaplastic (neuroendocrine) carcinomas primary in lung, five cases of bronchopulmonary carcinoids, and two cases of pheochromcytoma; both the carcinoids and pheochromocytomas had neurosecretory granule-rich cytoplasm by routine electron microscopy and some neurosecretory granules were identified in each of the small cell carcinomas. Immunolabeling for chromogranin A resulted in many colloidal gold particles over cytoplasmic secretory granules in both pheochromcytomas and four of the carcinoids. One carcinoid that was focally positive by immunoperoxidase staining was negative by immunoelectron microscopy. None of the 15 cases of small cell carcinoma stained for chromogranin A using immunoperoxidase techniques, but three had a small number of secretory granules weakly labeled by the anti-chromogranin A/colloidal gold complex. Immunoelectron microscopy, at least using standard glutaraldehyde fixation and epoxy resin embedding, does not increase the sensitivity of neurosecretory granule identification in small cell neuroendocrine carcinomas of the lung. Results of other studies of this neoplasm suggest that despite transcription of chromogranin genes, synthesis of the specific protein may occur to a limited extent or not at all.

Intraoperative detection of somatostatin-receptor-positive neuroendocrine tumours using indium-111-labelled DTPA-D-Phe1-octreotide

After injection of 111In-labelled DTPA-D-Phe1-octreotide, intraoperative tumour localisation was performed using a scintillation detector in 23 patients with neuroendocrine tumours. Count rates from suspect tumour lesions and adjacent normal tissue were expressed as a ratio before (Rin situ) and after (Rex vivo) excision. 111In activity concentration ratios of tumour tissue to blood (T/B) were determined in a gamma counter. In patients with midgut carcinoids, (all scintigraphy positive), false Rin situ recordings were found in 4/29 macroscopically identified tumours. T/B ratios were all high (27-650). In patients with medullary thyroid carcinomas (eight out of ten scintigraphy positive), misleading Rin situ results were found in 4/37 macroscopically identified tumours. T/B ratios were lower (3-39) than those seen in midgut carcinoids. Two out of four patients with endocrine pancreatic tumours had positive scintigraphy, reliable intraoperative measurements and very high T/B ratios (910-1500). One patient with a gastric carcinoid had correct measurements in situ and ex vivo with high T/B ratios (71-210). In situ measurements added little information to preoperative scintigraphy and surgical findings using the present detection system. Rex vivo measurements were more reliable. The very high T/B ratios seen in midgut carcinoids and some endocrine pancreatic tumours would be favourable for future radiation therapy via somatostatin receptors.

Pathophysiology of the fundic enterochromaffin-like (ECL) cell and gastric carcinoid tumours

The genesis of human gastric carcinoma is ill understood but is invariably related to achlorhydria. Gastrin secretion is negatively regulated by luminal acid and hypergastrinaemia is thus associated with low acid states which may be natural (atrophic gastritis) or owing to acid inhibitory therapy. Apart from its acid secretory activity, gastrin is trophic to the mucosa, via stimulation of the fundic enterochromaffin-like (ECL) cells to secrete histamine. In conditions of elevated gastrin levels, ECL cell hyperplasia and even neoplasia have been noted. The relationship between low acid, hypergastrinaemia, ECL cell hyperplasia, and neoplasia may be of relevance since ECL cells secrete histamine and TGF alpha which are both recognised mitogens. We studied the rodent mastomys, which spontaneously develop gastric carcinoid tumours, which can be generated in 4 months under conditions of drug-induced acid inhibition and inhibited by octreotide administration. A pure (90-95%) cell preparation was used to evaluate ECL cell physiology and trophic regulation. A gastrin/CCKB receptor responsible for histamine secretion and DNA synthesis was identified, cloned and sequenced. Octreotide lowers plasma gastrin levels, decreases ECL cell neoplasia and, in vitro, inhibits ECL cell DNA synthesis. H1 receptor antagonists inhibited DNA synthesis in vitro and ECL neoplasia in vivo without altering gastrin levels. Hypergastrinaemia increased TGF alpha/EGF receptor and TGF alpha production and TGF alpha massively stimulated ECL cell DNA synthesis. Since ECL cells produce both histamine and TGF alpha and regulate parietal cells which produce TGF alpha, it is possible that achlorhydria-generated ECL cell dysfunction may play an initiative role in the pathobiology of gastric adenocarcinoma. The long-term clinical consequences of drug-induced sustained acid inhibition are worthy of further consideration.

Primary ovarian carcinoid: a mixture of insular, trabecular and mucinous components

A case of primary ovarian carcinoid in a 53-year-old woman is described. The tumor which replaced the left ovary showed a mixture of insular, trabecular and mucinous cell types in the same mass. The nature of the neoplastic cells has been verified by light and electron microscopic studies. The latter investigation demonstrated bundles of tonofilament and apical villi of the trabecular cells in addition to the morphologic difference of neurosecretory granules among these various cells.

[Carcinoid lung tumors: clinico-morphologic characteristics, diagnosis]

Review of the literature on carcinoid lung tumors covers classification, macro- and microscopical structure, prognosis of typical and atypical carcinoids, role of special staining methods and electron microscopy in their diagnosis. The role of electron microscopy in the diagnosis of a rare structural variant, oncocytic carcinoid, is emphasized.

Neuroendocrine neoplasms of the larynx. Importance of the correct diagnosis and differences between atypical carcinoid tumors and small-cell neuroendocrine carcinoma

Findings in the present study have confirmed that the diagnosis of neuroendocrine tumors of the larynx (NETL) requires that a panel of neuroendocrine markers and electron microscopy be performed. This means that the clinician must be aware of the clinical presentations of such patients and should send fresh biopsy specimens to the clinical laboratory for optimal tissue studies. As shown in this study, the possibility of misdiagnosis of an atypical carcinoid tumor (ACT) is rather high. In establishing a diagnosis, a part of the material should be fixed for conventional histology, a part for immunohistochemistry and a part for electron microscopy. The correct diagnosis of NETL is obviously of great importance for subsequent treatment and prognosis. Patients with the diagnosis of ACT of the larynx require surgical treatment. Our findings also show that small-cell neuroendocrine carcinomas of the larynx should be considered to be a disseminated disease at initial presentation. A metastatic workup is necessary, but radical surgical procedures should be avoided. The combination of radiotherapy and chemotherapy is always indicated.

Carcinoid tumor of the renal pelvis: report of a case with positive urine cytology

A case of histologically and ultrastructurally confirmed carcinoid tumor of the renal pelvis is reported. The patient's urine sediment showed a few groups and sheets of polygonal malignant cells with scant cytoplasm and oval nuclei displaying chromatin clumping and micronucleoli.

Well-differentiated endocrine tumours of the middle ear and of the hindgut have immunocytochemical and ultrastructural features in common

The immunocytochemical analysis of two cases of well-differentiated endocrine tumours (carcinoids) of the middle ear revealed predominant cell populations producing pancreatic polypeptide (PP)-related peptides, glucagon-related peptides, and serotonin (the latter only in one case). In consecutive sections PP- and glucagon-related immunoreactivities mainly colocalized in the same tumour cells. Ultrastructurally tumour cells were characterized by medium-sized to large granules of moderate to high density, on which PP and glicentin were localized by the immunogold technique. No amphicrine cells were found. These features are consistent with those of similar tumours in the rectal mucosa that are mainly composed of L cells coexpressing both PP-related and glucagon-related peptides. Additional tumour antigens of hindgut type detected immunohistochemically were prostatic acid phosphatase and CAR-5 mucin. Expression of the CAR-5 antigen was also found in samples of normal middle ear mucosa, in which endocrine cells have not been identified. In case 1 peritumoral mucosal invaginations showed a proliferation of endocrine cells identical immunophenotypically to tumour cells, possibly representing a precursor lesion. It is concluded that well-differentiated endocrine tumours of the middle ear are a distinct pathological entity characterized by multiple hormone production, typically involving three classes of hormones (pancreatic polypeptide-related peptides, glucagon-related peptides, and serotonin) of the hindgut endocrine system.

Primary renal carcinoid tumor with molecular abnormality characteristic of conventional renal cell neoplasms

Carcinoid tumor of the kidney is a rare neoplasm of uncertain histogenesis. Attempts to elucidate its cell of origin have been made, but there is a lack of experimental proof. We present a case of primary renal carcinoid tumor with a characteristic molecular abnormality and discuss its histogenetic implications. Histologic, immunohistochemical, and electron microscopic analyses revealed features typical of carcinoid tumor, and DNA flow cytometric analysis showed diploid pattern. Molecular genetic studies of informative WT1, p53, and 3p21 loci revealed loss of heterozygosity only at the D3F15S2 locus (3p21 telomeric). The similarity between the molecular abnormality in the present case and that in most renal cell carcinomas suggests a possible common genetic event in the genesis of these neoplasms.

Divergent differentiative histogenetic lines in lung tumors: identification of histotypes with pure or mixed ultrastructural phenotype and their prognostic significance

We performed an electron microscopic study of 50 lung tumors, previously diagnosed by light microscopy, and compared the results of the two techniques. Data analysis identified two ultrastructural phenotypes: pure and mixed. The former was characterized by a constant differentiative pattern and the latter by diverging differentiative histogenetic lines. We observed six differentiative lines as follows: squamous, glandular, neuroendocrine, villopodial, intestinal, and apocrine sudoriparous. Features of divergent differentiative lines were observed in 36 cases (64%), throughout the histotypes, sometimes with coexpression of more than one differentiation in a single case and/or cell. Adenocarcinoma was the histotype most frequently observed in pure form whereas most squamous cell carcinomas showed a mixed phenotype. This suggests that the histotype of the different lung tumors arises from a single glandular pluripotent cell, able to differentiate toward divergent differentiative lines. The clinical stage at onset and at the end of the follow-up indicates that the biologic behavior of lung tumors varies according to whether the ultrastructural phenotype is pure or mixed.

Alteration in length of telomeric repeats in lung cancer

We investigated the relationship between telomere length and various characteristics of tumor cells in 46 lung cancer specimens (40 primary lesions and six metastatic lesions). Three variant patterns of telomere length were observed in 16 cases (34.8%): reduction in 13 cases, elongation in two cases, and convergence in one case. These variant patterns were frequently observed in small cell carcinomas, in metastatic lesions, and in cases which possessed the S-type allele of the L-myc gene. All three cases with telomere elongation or convergence were associated with a poor prognosis. This is compatible with the previous report suggesting that telomerase activity may be an indicator of immortality in vitro. In adenocarcinoma, telomere reduction or elongation was also observed in the early stages with a low percentage of cells in the S-phase, while in cases with other histologic types, these changes were observed only in late stage, in metastatic lesions, or in cancerous tissues with a high percentage of cells in the S-phase. Although the reduction of telomere length in these tissues may be a result of many cell divisions, it may represent another stage of carcinogenesis in early-stage adenocarcinoma.

[Cytologic findings on chronic inflammatory disease of the vocal folds]

The usefulness of cytologic diagnosis in laryngeal pathology is still controversial, also in the cytopathologist's opinion. A sampling procedure such as routine cytodiagnosis can be considered useful for both diagnosis and treatment of non-surgically related laryngeal diseases. This study was designed in order to demonstrate how cytodiagnosis can be useful in etiologic and pathogenetic diagnosis of chronic non-specific inflammatory diseases of the vocal folds. Cytologic sampling was carried out on brushing material of simple and hyperplastic laryngeal inflammations and on normal vocarfolds which were used as control. Through cytologic examination it was possible to evidence specific morphological findings which allowed differentiation of not only healthy from diseased vocal cords, but also hyperplastic from simple inflammatory processes. Moreover, the high incidence of goblet cells and cylindric squamous metaplasia in hyperplastic corditis, as well as the frequent presence of fungal involvement in the simple forms, prompted the Authors to hypothesize pathogenetic mechanisms as well as progression inducing factors of the pathologies in question.

Gastric carcinoid tumor and its precursor lesions. Ultrastructural study of a case before and after antrectomy

Antrectomy has been proposed as the preferential treatment of hypergastrinemic patients with nonantral gastric carcinoids since it removes the main growth factor for the tumors and their precursor lesions, ie, hypergastrinemia. To investigate the cellular basis of the mechanism for postantrectomy regression in nonantral endocrine cells, a light and electron microscopic morphometric study was performed in a case of enterochromaffinlike-cell gastric carcinoid associated with hypergastrinemia before and 4 and 10 months after antrectomy. The withdrawal of sustained hypergastrinemia obtained by antrectomy was associated with a progressive reduction of the volume density, cross-sectional area, and number of profiles of endocrine cells in the remaining nonantral mucosa, in which gastrin-dependent proliferations were regarded as the carcinoid precursor lesions. Ultrastructural morphometry demonstrated that the changes selectively involved the enterochromaffinlike cells, ie, the specific cell target for the trophic action of gastrin and the usual component of gastric carcinoids. The volume fractions of enterochromaffin and X cells (producing serotonin and endothelin, respectively) were increased 10 months after antrectomy. Persistence of a modest elevation of gastrin levels, likely due to the occurrence of gastrin cells in areas of pyloric metaplasia of the nonantral mucosa, did not prevent the hypotrophic effects of antrectomy.