Oat-cell carcinoma of the lung. Clinical and morphological studies in relation to its histogenesis

CXCL13 is expressed in a subpopulation of neuroendocrine cells in the murine trachea and lung

The conducting airways are lined by distinct cell types, comprising basal, secretory, ciliated, and rare cells, including ionocytes, solitary cholinergic chemosensory cells, and solitary and clustered (neuroepithelial bodies) neuroendocrine cells. Airway neuroendocrine cells are in clinical focus since they can give rise to small cell lung cancer. They have been implicated in diverse functions including mechanosensation, chemosensation, and regeneration, and were recently identified as regulators of type 2 immune responses via the release of the neuropeptide calcitonin gene-related peptide (CGRP). We here assessed the expression of the chemokine CXCL13 (B cell attracting chemokine) by these cells by RT-PCR, in silico analysis of publicly available sequencing data sets, immunohistochemistry, and immuno-electron microscopy. We identify a phenotype of neuroendocrine cells in the naïve mouse, producing the chemokine CXCL13 predominantly in solitary neuroendocrine cells of the tracheal epithelium (approx. 70% CXCL13⁺) and, to a lesser extent, in the solitary neuroendocrine cells and neuroepithelial bodies of the intrapulmonary bronchial epithelium (< 10% CXCL13⁺). In silico analysis of published sequencing data of murine tracheal epithelial cells was consistent with the results obtained by immunohistochemistry as it revealed that neuroendocrine cells are the major source of Cxcl13-mRNA, which was expressed by 68–79% of neuroendocrine cells. An unbiased scRNA-seq data analysis of overall gene expression did not yield subclusters of neuroendocrine cells. Our observation demonstrates phenotypic heterogeneity of airway neuroendocrine cells and points towards a putative immunoregulatory role of these cells in bronchial-associated lymphoid tissue formation and B cell homeostasis.

Endocrine Differentiation in Basal Cell Carcinoma

Argyrophilic cells have been found in 2 different basal cell carcinomas (BCC), and membrane-bound endocrine-like granules, in the carcinoid range, have been observed in 4 consecutive cases of such tumors. It is postulated that BCC can occasionally display cells showing an endocrine differentiation.

Origins, genetic landscape, and emerging therapies of small cell lung cancer

Lung cancer is the leading cause of cancer deaths, with small cell lung cancer (SCLC) representing the most aggressive subtype. Standard treatments have not changed in decades, and the 5-year survival rate has remained <7%. Genomic analyses have identified key driver mutations of SCLC that were subsequently validated in animal models of SCLC. To provide better treatment options, a deeper understanding of the cellular and molecular mechanisms underlying SCLC initiation, progression, metastasis, and acquisition of resistance is required. In this review, we describe the genetic landscape of SCLC, features of the cell of origin, and targeted therapeutic approaches.

Plasma ACTH in patients with bronchogenic carcinoma

Immunoreactive ACTH before and five hours after administration of 2 mg of dexamethasone was determined in patients examined in hospital for abnormalities on chest X-ray. Thirty patients had primary bronchial cancer, 15 had other lung conditions, mostly inflammatory infiltrations. The mean total ACTH and ACTH after dexamethasone suppression were significantly higher in the patients with bronchial cancer than in patients with other lung lesions or healthy controls. ACTH in plasma after administration of glucocorticoids was predominantly big ACTH. Several of the cancer patients had, however, ACTH levels within the same range as the other subjects. These results indicate that plasma ACTH determinations are of limited value as tumour markers for the detection of lung cancer although it is still possible that repeated sampling in patients with elevated ACTH levels may be of value when monitoring the therapy.

Primary small cell neuroendocrine tumour of the breast

Primary neuroendocrine carcinomas of the breast are extremely rare. Tumours can only be considered small cell neuroendocrine tumour of the breast if nonmammary sites are excluded. These tumours form a diagnostic and therapeutic challenge. We present our experience of small cell neuroendocrine tumour of the breast and discuss a review of the relevant literature.

Differential diagnostic patterns of lung neuroendocrine tumours

A series of 3 tumourlets (TLs), 81 typical carcinoids (TCs), 14 atypical carcinoids (ACs) (well-differentiated neuroendocrine carcinomas, WDNCs) and 24 small cell-intermediate cell carcinomas (SCC-ICCs) of the lung were studied. Histopathological features were correlated with amine and peptide hormone immunoreactivity and with clinical data. All types of tumours expressed general neuroendocrine (NE) markers: Grimelius positivity and chromogranins were detected more frequently in well-differentiated (TLs, TCs) than in less well differentiated tumours [ACs (WDNCs) and SCC-ICCs] whereas neuron specific enolase (NSE) was prominent in the latter tumours. TLs and peripheral TCs were benign, often showing a paraganglioid pattern and frequently expressing gastrin-releasing peptide (GRP), which is present in the peripheral airways of normal lung. Central TCs were associated with lymph node metastases in 8.5% of the cases, frequently had a trabecular architecture, often associated with human milk fat globule 2 (HMFG2)-positive acinar and rosette-like structures, and were mainly immunostained for the alpha-subunit of human chorionic gonadotrophin (alpha-hCG) and serotonin. ACs (WDNCs) were associated with intrathoracic and/or extrathoracic metastases in 57.1% of the cases with a mortality rate of 35.7%. Their histological and cytological features were intermediate between those of TCs and SCC-ICCs. ACs (WDNCs) expressed serotonin and alpha-hCG less frequently than TCs. All SCC-ICCs were surgically treated and displayed a mortality rate of 91.6% with a mean survival of 10.2 months after operation. These tumours were characterized by high expression of HMFG2 and NSE, while the expression of both orthotopic (serotonin, GRP) and ectopic (ACTH) specific NE substances was very low. Since all TCs (either central or peripheral) had a favourable outcome, while about 36% of ACs (WDNCs) were fatal, the latter seem more appropriately designated "well-differentiated NE carcinomas". The differential diagnosis between different NE tumours of the lung is important and is mainly based on morphology. Both panendocrine and specific immunohistochemical markers are helpful in distinguishing the less aggressive, mostly benign varieties from the more malignant varieties.

Primary oat cell (neuroendocrine) carcinoma of the breast. Report of four cases

Four cases of oat cell (neuroendocrine) carcinoma of the breast are reported. Three patients died within 15 months of the diagnosis and the fourth patient is alive after 44 months. Histochemical, ultrastructural and mRNA markers of endocrine differentiation were present in three cases. These tumours show histological similarities to breast metastases of bronchial oat cell carcinoma, but a distinguishing feature is the presence of in situ ductal lesions. It appears that the breast is a further site which has to be added to the long list of extrapulmonary oat cell carcinomas.

Tumorlets of the lung--an ultrastructural study

A tumorlet of the lung is a minute tumorlike lesion found in damaged lungs in close association with the bronchioles. Histochemical and ultrastructural studies identify proliferating cells in the tumorlets as Kultschitzky-type cells. However, the pathological significance of the tumorlets, whether they are hyperplastic or neoplastic, is still controversial. Previous ultrastructural studies on the tumorlets have been carried out on formalin-fixed lung tissues. The case examined in this study was of typical tumorlets found in a so-called middle lobe syndrome of the lung of a 52-year-old woman. Tumorlets were located within the bronchiolar mucosa surrounded directly by a basal lamina and by the bronchiolar nonendocrine epithelial cells. There were no signs of invasion into the surrounding connective tissues or into lymphaticlike spaces. Between the covering bronchiolar epithelial cells and the subjacent proliferating Kultschitzky cells, specific sites of cell-to-cell attachment were noted. This finding, in addition to previously reported clinicopathological characteristics, indicates that the proliferating Kultschitzky-type cells in the tumorlets might be non-neoplastic and that tumorlets are due to hyperplasia of pure Kultschitzky-type cells, thus resembling neuroepithelial bodies of the lung.

Small cell lung carcinoma: clinicopathological, immunohistochemical, and ultrastructural study

Sixty-seven cases of small cell lung carcinoma (SCLA) in Tri-Service General Hospital (TSGH) during the past 16 years were studied. For patients with extensive stage of disease, the mean survival time and 2-year survival rate were 7.2 months and 3.1% versus 13.4 months and 16.7% for patients with limited stage. A better prognosis was obtained by treatment with a combination of intensive chemotherapy and radiotherapy. Immunohistochemical studies were performed by the peroxidase-antiperoxidase method. The positive rates in descending order were bombesin (80%), synaptophysin (74.3%), neurofilament (68.6%), neuron-specific enolase (60%), low molecular weight cytokeratin (54.3%), high molecular weight cytokeratin (25.7%), chromogranin-A (22.9%), adrenocorticotrophic hormone (0). Seven cases were examined and found to be ultrastructure; only 3 cases were found to contain neurosecretory granules. We emphasize that electron microscopy is not necessary as a routine diagnostic procedure, while light microscopy should be employed whenever possible; the immunohistochemical study should be considered within this context.

Type C retroviral expression in spontaneous feline olfactory neuroblastomas

Three cases of spontaneous olfactory neuroblastoma (ONB) in domestic cats were morphologically and immunocytochemically characterized. Diagnostic light microscopic features included Flexner and Homer-Wright rosettes, while ultrastructurally the cells had neuritic processes, intracellular intermediate filaments, and intercellular junctions. Immunocytochemically, the tumors stained positively for neuron-specific enolase, cytokeratins, and S-100 protein antigens. In each case, a key finding was the identification of numerous mature type C retroviral particles within the tumors. In one case, budding of viral particles from the plasmalemma of tumor cells suggested the source of mature particles. This cat and one other were tested, and both were serologically positive for feline leukemia virus (FeLV). The virus in the tumors was identified as FeLV by polymerase chain reaction and immunocytochemistry. No other neoplasms were found in any of the cats, nor was there similar evidence of active viral infection in other non-tumor tissues, including the brain. Although the relationship between FeLV infection and ONB is uncertain, our findings indicate that FeLV should be investigated as an etiologic agent of ONB.

What's new in lung tumor heterogeneity?

The categorization of lung tumors into histologically defined groups and subtypes is based on morphometric criteria, on various degrees of tumoral differentiation and growth patterns. Light microscopic examination of different sections of one and the same tumor reveals in more than 30% of the cases investigated a qualitative and quantitative heterogeneous cell and tumor growth pattern, which is further proved by additional immunohistochemical, electronmicroscopic and DNA-flow cytometry studies. According to observations on the ultrastructural level mixed or combined morphologic features signaling abnormal differentiation patterns in preneoplastic lesions of the bronchial mucosa were visible. So-called amphicrine cells containing mucous vacuoles as well as granules of neurosecretory type were found in basal cell and goblet cell hyperplasia. Squamous-type cells predominate in epidermoid metaplasia and in dysplasia. Cells containing mucous granules or tonofilaments and scant granules of dense core-type suggestive of squamous neurosecretory differentiation were present in all lesions. The ultrastructural features were correlated with the bronchial carcinoma cell heterogeneity and histogenesis.

Multiple peptide hormone producing adenocarcinoma of lung with neurotensin and CRF-like immunoreactivity

A pulmonary cancer of a 43 year-old-man was classified according to WHO-criteria as a poorly differentiated adenocarcinoma because of demonstration of mucinous substances in tumor cells and in rarely occurring acinar lumina. Immunohistochemical reactivity for several peptide hormones was detected in the predominant solid parts of the carcinoma. In many tumor cells an immunoreactivity to neurotensin, bombesin and - according to the elevated serum levels - to ACTH, CRF and calcitonin was found. Therefore the present lung cancer must be defined as a combined carcinoma composed of mucous producing and endocrine cell types. Because peptide hormone production is not restricted to the classical "neuro"-endocrine lung tumors, the histogenesis of this heterogeneous lung cancer is discussed.

Asbestos-induced fibrosis in rats: increase in lung mast cells and autacoid contents

Adult male Wistar rats were treated with one tracheal instillation of 5 or 10 mg chrysotile B asbestos fibers in 0.5 ml saline, or 0.5 ml saline only (controls). Rats were killed at 1, 3, and 6 months postinstillation. Serotonin and histamine were quantitated in lung tissue homogenate using high-performance liquid chromatography with electrochemical and fluorometric detection, respectively. Serotonin was also quantitated in the cytoplasm of grouped (NEB) and individual (NEC) neuroendocrine cells and in mast cells using formaldehyde vapor-induced fluorescence and microspectrofluorometry, and density indices of NEBs, NECs, and mast cells were determined. Tissue edema, fibrotic lesions, and medial hypertrophy of pulmonary arterioles were assessed morphometrically. Test rats had higher pulmonary serotonin and histamine levels than controls at 1, 3, and 6 months. They also had higher cellular serotonin in NEBs at 1 month, but not in NECs, and tended to have higher serotonin levels in mast cells at 6 months. Mast cell numbers were higher among tests at 1 and 3 months, whereas NEBs and NECs were unchanged by asbestos. There was no difference between tests and controls in the amount of tissue edema at any time. However, all test rats had distinct lung lesions characterized by peribronchiolar fibrosis and bronchiolitis obliterans. No such lesions were present among control rats. Typically, mast cells were located immediately beneath the epithelial basal lamina of the bronchiolar fibrotic projections and at their stalks, whereas no mast cells were noted beneath normal epithelium, indicating a role of mast cells in asbestos-induced peribronchiolar fibrosis. Moreover, arteriolar medial hypertrophy at all three ages in conjunction with the increased levels of serotonin was an index of putative chronic pulmonary hypertension. Our results suggest that asbestos-induced rises in serotonin and histamine are due primarily to increased numbers of mast cells.

Extraskeletal Ewing's sarcoma

A well documented case of extraskeletal Ewing's sarcoma arising in a finger of a 16-year-old man was studied by light microscopy, immunohistochemistry and electron microscopy. The differential diagnoses of similar "round cell neoplasms" are discussed. Emphasis is placed on the distinction between extraskeletal Ewing's sarcoma and peripheral neuroepithelioma.

Application of Grimelius argyrophil staining to the study of tumour ultrastructure. I. Effects of fixatives

Two methods have so far been proposed for staining samples by the argyrophil technique of Grimelius for electron microscopy. For Håkanson glutaraldehyde prevented argyrophilia, so the author stained sections from samples previously fixed by double formaldehyde/osmium tetroxide treatment and embedding. Vassallo used en bloc staining after fixation with glutaraldehyde-formaldehyde mixtures. We examined each factor which could directly interfere in argyrophil staining en bloc and on section. In the present experiment we compared effects of fixatives after staining en bloc. Glutaraldehyde prevented argyrophilia in 1 case out of 15, that of A-like cells in the oxyntic gland of the rat positivity was maintained in EC-like cells of this gland and adrenalin cells of the adrenal gland contrary to the previous description.

Intercellular junctions and tumor stage in small cell carcinoma of the lung

The authors have studied the ultrastructural features of 52 cases of oat cell carcinoma of the lung and have related their observations to tumor stage and patient survival. Only the type of cell junctions seems to be of prognostic importance. Tumors with intermediate junctions--and especially those with desmosomes--have a more localized stage and may be resectable to result in longer survival than expected for oat cell carcinomas without junctions. For example, in the authors' series the median survival periods for those with no identifiable junctions, intermediate junctions, or desmosomes were 6.4, 8.2, and 11.3 months, respectively. Nevertheless, this ultrastructural subclassification is not as effective as that obtained from careful clinical staging.

Biological, pathological and clinical features of small cell lung cancer

Small cell lung cancer, which is not uncommon, and is one of the most malignant and relatively well investigated solid tumors of adults, has been reviewed concerning its biology, pathology and clinical aspects. Although it is histologically very simple, its poorly differentiated epithelial cell characteristics are complicated by features of neuroendocrine cells, such as amine and peptide hormone production and specific enzyme activities, some of which have been found to be good monitoring markers during and after treatment. Because of the relative ease of establishing cell lines in vitro, cell characteristics have been studied in detail. This has led to subtyping of cell lines and may further lead to subtyping of histology. However, accumulation of further evidence has disclosed exceptions and unclassifiable cell lines. The same can be said about chromosomal abnormality. The reactivity of monoclonal antibodies and also oncogenes supports the prevalent concept discriminating small cell cancer from non-small cell cancer. However, concepts concerning histogenesis are still changing. Although it is one of the solid tumors most sensitive to radiation and chemotherapy, the response rate of the tumor to non-surgical treatment appears to have reached a plateau. In order to make a breakthrough in the treatment, strategies based on biological findings must be applied.

Subtypes of small cell carcinoma of the lung: morphometric, ultrastructural, and immunohistochemical analyses

Fifty-three surgically resected small cell carcinomas of the lung were studied morphometrically, electron microscopically, immunohistochemically, and in terms of possible site of origin. Four subtypes of small cell carcinomas were identified: oat cell carcinoma (OAT), small cell carcinoma of the intermediate cell type (INT), combined oat cell carcinoma, and undifferentiated carcinoma of the small cell type (UCS). The latter type is presumed to be non-neuroendocrine. Morphometric analysis showed considerable overlap among OAT, INT, and UCS with respect to nuclear area, cell area, and nuclear/cytoplasmic ratio. Ultrastructurally, significantly more carcinomas categorized as OAT and INT contained neurosecretory granules than did those in the UCS category (P less than 0.01 and 0.05, respectively). Cells with tonofibrils were more frequent in UCSs than in OATs and INTs. Immunohistochemically, fewer UCSs than OATs contained cells with gastrin-releasing peptide, neuron-specific enolase, and Leu-7 (P = 0.5, P less than 0.05, and P less than 0.05, respectively). UCSs were located more frequently at the periphery of the lung than were OATs (P less than 0.01) and INTs (P = 0.06). These findings suggest that UCS may be a pathologic entity distinct from the typical neuroendocrine-type small cell carcinoma and that this subtype probably corresponds to small cell carcinoma with a "large cell component," and to very poorly differentiated adenocarcinoma and squamous cell carcinoma of the small cell type.

Expression of epithelial and neural antigens in small cell and non small cell lung carcinoma

Seventy-one lung carcinomas from 66 different patients were stained with a panel of monoclonal antibodies. Twenty-nine were small cell lung carcinoma (SCLC), 15 adenocarcinomas, 17 squamous carcinomas and 10 large cell carcinomas. Three of the monoclonal antibodies recognize different cytokeratins, three recognize other epithelial antigens and one recognizes a neural antigen. Both formalin-fixed and cryopreserved tumours were studied using an indirect immunoperoxidase method. 23/29 SCLC reacted with all but one of the antibodies which recognize epithelial antigens. This staining was similar to that seen in non small cell lung carcinomas (NSCLC) and provides further evidence that SCLC are true epithelial tumours. All but one of the SCLC stained with the antibody recognizing a neural antigen. This antibody did not stain squamous or adenocarcinomas. However, four of the large cell carcinomas stained well with this antibody, suggesting that SCLC and some large cell carcinomas share a common pathway of differentiation. There were variations of staining seen both within and between tumours. This has obvious implications if immunotargetting with monoclonal antibodies is to be used diagnostically or therapeutically.

Prevalence of neuroendocrine granules in small cell lung carcinoma. Usefulness of electron microscopy in lung cancer classification

Fifty-four lung carcinomas submitted for routine electron microscopy under the light microscopical diagnosis of small cell carcinoma were investigated. In 42 or of 45 evaluable cases, neuroendocrine granules were considered definitely or probably present, the modification 'probably' being necessary in suboptimal material. In three cases, squamous cell differentiation was seen, but no neuroendocrine granules were found. On revision of these three cases, the light microscopical diagnosis was changed to squamous cell carcinoma in one instance, and neither of the other two cases was considered classical for small cell carcinoma. Patient follow-up of these three cases showed tumour behaviour indicative of non-small cell carcinoma in two evaluable cases, the third case yielding no significant data. These results indicate that neuroendocrine granules can generally be found in small cell lung carcinomas, provided the material is sufficient for evaluation. When these granules are absent, and other differentiation is found on electron microscopy, the final classification of the tumour should incorporate this finding, to warn the clinician that the tumour will not necessarily behave as a small cell carcinoma.

Paraneoplastic syndromes, tumor markers, and other unusual features of malignant melanoma

Malignant melanoma is a neoplasm associated with a wide variety of paraneoplastic syndromes. In this review the many paraneoplastic syndromes associated with malignant melanoma are critically reviewed. Unusual nonparaneoplastic associations with malignant melanoma and tumor markers for malignant melanoma are discussed.

Neurofilaments of Kultschitsky cells in human lung

The immunohistochemical localization of three triplet proteins of neurofilaments in normal Kultschitsky cells and tumourlets of the human lung has been studied using avidin-biotin-peroxidase complex (ABC) method. Kultschitsky cells and tumourlets have been stained with antisera against 68 K, 150 K and 200 K dalton components of the neurofilaments, respectively. Ultrastructural observations of human Kultschitsky cells have revealed the presence of bundles of intermediate filaments as well as microtubules and neurosecretory-type granules. In the tumourlets, similarly sized filaments were found, but were relatively scarce. Since intermediate filaments are thought to be specific to differentiated cells and neurofilament proteins are restricted to the neuronal tissues, we conclude that Kultschitsky cells of the lung are of neuronal nature.

The ultrastructure of small cell lung carcinoma in bronchial biopsy specimens

Forty-three bronchial biopsy specimens from patients with small cell lung cancer (SCLC) were studied by electron microscopy. In 38 specimens the diagnosis was based on the light microscopic examination of Epon-embedded tissue; 36 of these specimens contained dense-core granules on electron microscopic examination. In five cases the light microscopic diagnosis was either different from the electron microscopic diagnosis or in doubt. Electron microscopy revealed dense-core granules as the only sign of differentiation, and the diagnosis was changed to SCLC. The tumor cell populations in the biopsy specimens were quite heterogeneous. Cells of the oat cell type were always present and, on electron microscopic examination, always showed degenerative changes. It was therefore decided that this cell type represents an artifact. The true SCLC tumor cell, which constitutes only a small portion of the tumor in biopsy specimens, is characterized by a regular oval or rounded cell with pale cytoplasm and a ground-glass nucleus with finely dispersed chromatin. Nucleolated cells, similar to those seen in large cell cancer, are often present but are not ultrastructurally different from nonnucleolated tumor cells.

Multiple hormone production in an oat cell carcinoma of the larynx

A 60-year-old white woman with laryngeal oat cell carcinoma is described. She was a heavy smoker who had been treated seven years earlier with 5,000 rads for a well differentiated squamous cell carcinoma metastatic to a left submandibular lymph node. She presented this time with a two month history of hoarseness and tumor of the supraglottic larynx was found. There was clinical and chemical evidence of an ectopic ACTH syndrome. The histology and fine structure of the tumor were typical of oat cell carcinoma. Immunoreactive ACTH, GRP, NSE, Beta-endorphin, calcitonin, and keratin were found in the cytoplasm of the tumor cells by indirect immunoperoxidase techniques. We could find no previously reported case of laryngeal oat cell carcinoma with ectopic ACTH syndrome or cytoplasmic localization of polypeptides.

Ultrastructural features of metastatic cutaneous carcinoid

Tissue from the cutaneous metastases of bronchial carcinoid was examined. Fine argyrophil secretory granules were demonstrated in the cytoplasm of the abnormal cells which showed positive labelling with neuron-specific enolase. Ultrastructural studies revealed numerous electron-dense membrane bound neuro-secretory granules, 50-300 nm in diameter. Other characteristic features included inter-digitating pseudo pod-like processes (up to 2 mu in size) in the cytoplasmic membrane, perinuclear filaments, a well-defined Golgi zone and numerous large mitochondria.

Paraneoplastic syndromes and constitutional symptoms in prediction of metastatic behavior of small cell carcinoma of the lung

Small cell carcinoma of the lung is frequently associated with a paraneoplastic syndrome or constitutional symptoms. To examine correlations between paraneoplastic syndromes or constitutional symptoms and tumor behavior, the clinical and pathologic features were reviewed in 85 patients with small cell carcinoma of the lung who underwent complete autopsy at The Johns Hopkins Hospital between 1962 and 1983. The 28 (33 percent) subjects with a paraneoplastic syndrome survived significantly longer (10.5 +/- 1.5 months) than those without a paraneoplastic syndrome (7.4 +/- 0.7 months) (p less than 0.05), and they had significantly higher frequencies of tumor invasion into major bronchi (p less than 0.01) and more extensive metastases to bone marrow (p less than 0.05), but significantly lower frequencies of and less extensive metastases to the central nervous system (p less than 0.005). The 35 (41 percent) subjects with constitutional symptoms had markedly increased tumor burdens (p less than 0.005) with significantly more extensive metastases to bone marrow, liver, and lungs (all p less than 0.05). The findings suggest that subjects with small cell carcinoma of the lung associated with a paraneoplastic syndrome tend to have a more benign clinical course with prolonged survival; in addition, the significantly lower frequency of central nervous system metastases in these patients may be due to a paucity of the subpopulations of tumor cells that have the propensity to metastasize to the brain. In contrast, it appears that constitutional symptoms develop in patients with small cell carcinoma of the lung because of rapid tumor growth, coupled with impairment of synthetic activity in the liver due to extensive infiltration of tumor into hepatic parenchyma.

Extrapulmonary oat-cell carcinoma of the tongue: an electron-microscopic study

An extrapulmonary oat-cell carcinoma arose in the tongue of a 62-year-old man who had a long history of cigarette smoking and ethanol ingestion. At presentation, he had the primary tongue lesion and cervical lymph-node metastases only, and search for a pulmonary primary was negative. Ten months later he died with metastases to liver, cerebrum, ribs, vertebrae, calvarium, and clavicle. Electron microscopy demonstrated cells with cytoplasmic processes and many dense-core neurosecretory granules that had a tendency to concentrate in the processes. Cells were linked by desmosomes. Electron microscopy is necessary for definitive diagnosis of extrapulmonary oat-cell carcinomas.

Tumor cell colonies in bone marrow cultures from patients with small cell carcinoma of the lung

Bone marrow specimens from 27 patients with small cell carcinoma of the lung (17 with limited and 10 with extensive disease) were plated in a culture system that supports the growth of multilineage haemopoietic progenitors CFU-GEMM. In five patients (three with extensive and two limited disease) atypical colonies could be observed that were not identifiable as haemopoietic colonies. Cytological staining and cytochemical examination as well as electronic micrographs suggest that these colonies are derived from metastatic carcinoma cells. The histological examination of marrow cells from three out of these five patients revealed no bone marrow involvement. Additional studies might provide further evidence whether bone marrow cultures are a useful probe in order to monitor bone marrow involvement in patients with small cell carcinoma of the lung.

Immunocytochemical localization of neuron specific enolase in small cell carcinomas and carcinoid tumours of the lung

Carcinoid tumours and small cell carcinomas of the lung share many characteristics with normal neuroendocrine cells. While carcinoid tumours contain many dense-cored neurosecretory granules and are frequently argyrophil, small cell carcinomas are poorly granulated and rarely argyrophil, which casts doubt on their neuroendocrine nature. Immunostaining of the enzyme neuron specific enolase (NSE) was recently used to demonstrate the neuroendocrine components of the lung including nerves and neuroendocrine cells. We therefore used NSE immunostaining to investigate neuroendocrine differentiation in 79 lung tumours, including 18 bronchial carcinoids and 31 small cell carcinomas, and compared these results with those obtained with silver stains. Thirteen of the 18 carcinoids were reactive to silver, all other types being negative. NSE-immunoreactivity occurred in 16 carcinoids and 18 small cell carcinomas. None of the squamous cell carcinomas, large cell anaplastic carcinomas and adenocarcinomas examined showed NSE-immunoreactivity. Radioimmunoassay of extractable NSE from 10 fresh lung tumours correlated well with the immunostaining results, demonstrating large amounts in two small cell carcinomas (334 and 517 ng/mg protein) and three carcinoids (152, 908, and 1143 ng/mg protein). Values were much lower for four squamous cell carcinomas (31-44 ng/mg protein) and one large cell anaplastic carcinoma (30 ng/mg protein) and were accounted for by the presence of NSE-positive nerves and neuroendocrine cells in the surrounding lung. NSE immunostaining is a useful marker of neuroendocrine differentiation in lung tumours and should prove particularly valuable in the diagnosis of small cell anaplastic tumours and their metastases.

Diagnostic value of intermediate filament antibodies in clinical cytology

Antibodies to intermediate filament (IF) proteins can distinguish the major tumour groups as shown by results with sectioned human material. In this study we evaluate the use of similar methods in the cytology of human tumors. Smears obtained from fine needle aspiration biopsies were investigated using well characterized antibodies, each specific for only one of the five types of intermediate filaments. Tumor cells of different carcinomas, thymomas, and the epithelial part of pulmonary blastomas were positive with antibodies recognizing cytokeratins. Tumor cells in non-muscle sarcomas, including lymphoma and Ewing's sarcoma, could be specifically identified with antibodies to vimentin. Tumor cells of muscle sarcomas were desmin-positive. Finally, tumor cells in pheochromocytoma and bronchus carcinoid were positive with antibodies specific for neurofilaments. Specimens were also examined in parallel using conventional cytochemical stains, such as May-Grünwald-Giemsa. In addition, in most cases sections of the tumor were examined both by histology and IF typing of frozen sections to confirm the diagnosis made on the cytologic specimens. The results show that IF typing is a valuable diagnostic aid in clinical cytology.

Small cell neuroendocrine (oat cell) carcinoma of the male breast. Immunocytochemical and ultrastructural investigations

A case of small cell neuroendocrine (oat cell) carcinoma of the breast in a 52-year old male is presented. Oat cell carcinomas have been reported in various extrapulmonary sites, but this is the second case of a primary oat cell carcinoma of the breast and the first one to have been documented in a male. The tumor was investigated histologically, immunocytochemically and ultrastructurally. The relationship to so-called "carcinoid" mammary tumors is discussed.

Pulmonary carcinoid associated with a parathormone producing melanoma

A rare presentation of hypercalcemia secondary to the probable ectopic production of parathormone by a malignant melanoma associated with a pulmonary carcinoid is discussed. We suggest the association of melanoma with multiple endocrine neoplasia.

Electron microscopic sub-classification of small cell carcinoma of the lung

An electron microscopic study of 28 small cell carcinomas of the lung is presented. Cytoplasmic secretory granules, characteristic of endocrine cells of the human foetal lung were observed in a variable number of tumor cells. Two groups of tumors could be distinguished based on the morphology of the cytoplasmic secretory granules. Twenty-three tumors showed cells with granules resembling type 1 or P1 cells of the human fetal lung, and 5 tumors with granules resembling type 3 cells of the human fetal lung. No relationship was found between the light microscopic WHO classification of small cell carcinoma of the lung and the results obtained by electron microscopy. Increased serum calcitonin as well as inappropriate ADH secretion may be correlated with one of the two types of small cell carcinoma, but further investigations are needed.

Analysis of cell surface proteins delineates a differentiation pathway linking endocrine and nonendocrine human lung cancers

We have previously determined that the cell surface protein phenotype distinguishes human small cell lung carcinoma (SCC), a neoplasm with endocrine properties, from non-SCC in culture. We now demonstrate that cloned cell cultures of human large cell undifferentiated lung carcinoma, established directly from a patient with mixed SCC and non-SCC, simultaneously express surface proteins characteristic of SCC and non-SCC lung cancer cells. Hence, SCC and a form of large cell carcinoma appear linked through a continuum of differentiation events that: (i) may explain clinically important transitions that occur between the major types of human lung cancer and (ii) provide evidence for a common cellular origin of endocrine and nonendocrine cells in the bronchial mucosa.

Non-oat cell small cell carcinoma of the esophagus. Report of a case with ultrastructural observation

A resected case of undifferentiated, non-oat cell type small cell carcinoma of the esophagus in a 78-year-old Japanese male is presented. Biopsy of a lower esophageal tumor that showed protrusions and centrally ulcerated features on esophageal roentgenograms, was initially misinterpreted as probable malignant lymphoma, because the absence of epithelial arrangement and the presence of abundant fine reticulin fibers encircling individual tumor cells. However, sections of the resected specimen disclosed minute foci consisting of nest formations of tumor cells suggesting an epithelial nature. Electron microscopy demonstrated immature round tumor cells, some of which showed occasional villous projections, desmosomal attachment devices, intracytoplasmic filaments resembling primitive tonofilaments. No neurosecretory granules as have been reported in oat-cell carcinoma of the esophagus were identified in the present case. The results suggest that this tumor is derived from the primitive cells of the esophageal mucosal epithelium or the duct of the esophageal glands. This tumor should be discriminated from oat-cell carcinoma on the basis of its histogenesis.

Exocytosis of neurosecretory granules in small cell undifferentiated carcinoma

The tumor cells in the pleural effusions of a case of small cell undifferentiated carcinoma have been studied by light microscopy and by thin section and freeze-fracture electron microscopy. Evidence of exocytosis of neurosecretory granules from the tumor cells is presented. The tumor cells form clumps, with the cells joined by focal tight junctions and small desmosomes. These findings are discussed with reference to the neuroendocrine origin of these tumors and the role of the junctional complexes in the formation of tumor cell aggregates.

Prolonged survival of patients with extrapulmonary small cell carcinoma arising in the neck

Two patients with extrapulmonary small cell carcinoma localized in the neck survived for more than two years without systemic therapy. This suggests that there may be a subset of small cell carcinomas characterized by slow growth, resulting in an indolent clinical course. By light and electron microscopy, we were unable to identify features of this indolent form which differ from those of the aggressive form of pulmonary or extrapulmonary small cell carcinoma.

Peptide hormone production by adenocarcinomas of the lung; its morphologic basis and histogenetic considerations

The cell source of peptide hormone production and the morphological differentiation were investigated in 18 adenocarcinomas of the lung by immunohistochemistry and/or by electron microscopy. These tumors were found by radioimmunoassay of tumor extracts to contain either one or more of 7 peptide hormones, i.e. adrenocorticotropin (ACTH), beta- and gamma-melanocyte stimulating hormones (MSH), somatostatin (SS), vasoactive intestinal polypeptide (VIP), gastrin releasing peptide (GRP) and calcitonin (CT). In a combined adeno- and small cell carcinoma, a considerable number of small tumor cells were positively stained for ACTH, beta- and gamma-MSHs and GRP. In a poorly differentiated adenocarcinoma with mucin and CT production, these products were localized in some single cells. Electron microscopy revealed secretory granules indistinguishable from exocrine or endocrine types. In another mucin-positive adenocarcinoma with high SS and CT contents, some tumor cells were stained for SS and/or CT. Two distinct exocrine and endocrine type secretory granules were found in the same cells. In tumors with 100 ng or less of the peptides/g tissue, most tumor cells were not stained for the peptides but a small number showed morphological endocrine differentiation. In conclusion, a considerable proportion of the adenocarcinomas of the lung may show heterogeneous differentiation in both endocrine and exocrine directions.

Establishment and characterization of two neoplastic cell lines (U-1285 and U-1568) derived from small cell carcinoma of the lung

Two human cell lines have been established in vitro from patients with small cell carcinoma of the lung (SCC). The U-1285 line was derived from the classical small cell type of SCC while the U-1568 originated from a larger cell variant. The cell lines grow as suspension cultures and have been passaged continuously in vitro for 3 years (U-1285) and 2 years (U-1568), respectively. The malignant nature of the lines is suggested by their infinite growth potential, their capacity to form colonies in agarose and their aneuploidy. Both cell lines contain cytoplasmic electron dense particles indistinguishable from classical neurosecretory granules but only in U-1568 has hormone production (human chorion gonadotropin (alpha-HCG)) been proven. The U-1568 line produces carcino-embryonic antigen (CEA) while both U-1285 and U-1568 produce alpha-feto-protein (AFP). Chromosome analysis reveal aneuploidy of both lines. Among structural aberrations, involvement of chromosome 14 in U-1285 and chromosomes 1, 7 and 12 in U-1568 is interesting since alterations of these chromosomes have been described previously in other malignant conditions.