Neuroendocrine neoplasms and their cells of origin

Extracellular pH Modulates Neuroendocrine Prostate Cancer Cell Metabolism and Susceptibility to the Mitochondrial Inhibitor Niclosamide

Neuroendocrine prostate cancer is a lethal variant of prostate cancer that is associated with castrate-resistant growth, metastasis, and mortality. The tumor environment of neuroendocrine prostate cancer is heterogeneous and characterized by hypoxia, necrosis, and numerous mitoses. Although acidic extracellular pH has been implicated in aggressive cancer features including metastasis and therapeutic resistance, its role in neuroendocrine prostate cancer physiology and metabolism has not yet been explored. We used the well-characterized PNEC cell line as a model to establish the effects of extracellular pH (pH 6.5, 7.4, and 8.5) on neuroendocrine prostate cancer cell metabolism. We discovered that alkalinization of extracellular pH converted cellular metabolism to a nutrient consumption-dependent state that was susceptible to glucose deprivation, glutamine deprivation, and 2-deoxyglucose (2-DG) mediated inhibition of glycolysis. Conversely, acidic pH shifted cellular metabolism toward an oxidative phosphorylation (OXPHOS)-dependent state that was susceptible to OXPHOS inhibition. Based upon this mechanistic knowledge of pH-dependent metabolism, we identified that the FDA-approved anti-helminthic niclosamide depolarized mitochondrial potential and depleted ATP levels in PNEC cells whose effects were enhanced in acidic pH. To further establish relevance of these findings, we tested the effects of extracellular pH on susceptibility to nutrient deprivation and OXPHOS inhibition in a cohort of castrate-resistant prostate cancer cell lines C4-2B, PC-3, and PC-3M. We discovered similar pH-dependent toxicity profiles among all cell lines with these treatments. These findings underscore a potential importance to acidic extracellular pH in the modulation of cell metabolism in tumors and development of an emerging paradigm that exploits the synergy of environment and therapeutic efficacy in cancer.

Mixed adenoneuroendocrine carcinoma (MANEC) of the gallbladder: a possible stem cell tumor?

A 48 year-old African American woman presented to her physician complaining of a rapidly evolving epigastric and right upper quadrant abdominal pain. A PET-CT of the abdomen and pelvis demonstrated hypermetabolic, polypoid masses within the gallbladder and several tumors in the left lobe of the liver for which she underwent diagnostic laparoscopy. The gallbladder revealed a 3.5 × 3.3 × 2.4 tan-brown exophytic mass located at the fundus and growing into the lumen with multiple contiguous papillary projections arising from the mucosal surface. A concurrent large cell neuroendocrine carcinoma and papillary adenocarcinoma of the gallbladder was revealed histologically. There was shared reactivity to antibodies directed against the distinct antigens for each morphological component with transitional tumor cells (of both histological components) located at the areas where the two tumor types merged, revealing common immunoreactivity for carcinoembryonic antigen, cancer antigen 19-9, keratin 19, c-kit (cluster of differentiation protein 117 (CD117)) and epithelial cell adhesion molecule. Ultrastructurally, individual cells were demonstrated to have overlapping features of neuroendocrine and glandular differentiation. The aforementioned histological, ultrastructural and immunohistochemical profile is strongly suggestive of a biphenotypic stem/progenitor cell tumor of the gallbladder.

The Dispersed Neuroendocrine System, Its Bronchopulmonary Elements, and Neuroendocrine Tumors Presumed to be Derived from Them: Myths, Mistaken Notions, and Misunderstandings

The increasing recognition of the dispersed neuroendocrine system and its importance in human physiology has impacted our understanding of physiology, pathophysiology, and histopathology. It has been the subject of a great deal of controversy and debate, giving rise to certain misunderstandings. This article attempts to put some of these issues in perspective, especially as they relate to the bronchopulmonary tree.

Imaging of pheochromocytoma and paraganglioma

Paragangliomas are tumours that arise within the sympathetic nervous system originating from the neural crest. These tumours can be found anywhere from the neck to the pelvis in locations of sympathetic ganglions. Although in the majority of paragangliomas the diagnosis is based on measuring catecholamines and metabolites in plasma or urine, imaging plays an important preoperative role. Today, there are several morphological and radionuclide imaging methods available that predict tumour localisation and tumour extent and give anatomic information to the surgeon. MRI is the morphological imaging modality of choice in localising pheochromocytomas and extra-adrenal paragangliomas. It provides excellent anatomic detail and has the advantage of lacking ionising radiation. The overall accuracy of computed tomography (CT) in detecting primary adrenal pheochromocytomas is very high, but CT lacks in specificity as difficulties may occur in distinguishing between paragangliomas and other tumour entities. The major advantages of radionuclide imaging are very high specificity and routinely performed whole-body scanning. Furthermore, metabolic imaging is not influenced by artifacts like scar tissue or metallic clips in post-surgical follow-up. Currently, a reported specificity of 99% and a cumulative sensitivity of about 90% in paragangliomas make (123)I-MIBG the most important nuclear imaging method. However, (18)F-DOPA-PET seems to be a very promising procedure which offers higher accuracy. The higher spatial resolution of PET-scanners enables the detection of small lesions not visualised with (123)I-MIBG. Both use of radiolabelled somatostatin analogue like (111)In-pentetreotide and (18)F-FDG is limited due to low specificity of the tracers and should be restricted to MIBG- and F-DOPA-negative cases.

Origin of neuroblastic tumors: clues for future therapeutics

Neuroblastic tumors are the most common extracranial tumors of childhood. They arise from embryonal cells committed to the development of the sympathetic nervous system. In vivo and in vitro observations have shown that neuroblastic tumors appear to recapitulate the development of differentiating sympathetic neurons and chromaffin (neuroendocrine) cells of the sympathetic nervous system. This suggests that the origin of neuroblastic tumors resides as a block in the process of differentiation. This article summarizes the experimental data accumulated over the last three decades, which has provided some clues to the cellular origin of such tumors. In order to identify the cellular origin of these tumors, the embryology of the sympathetic nervous system is first reviewed and any archeological rests of normal development in the tumors are then discussed.

18F-DOPA positron emission tomography for the detection of glomus tumours

The purpose of this study was to evaluate (18)F-DOPA whole-body positron emission tomography ((18)F-DOPA PET) as a biochemical imaging approach for the detection of glomus tumours. (18)F-DOPA PET and magnetic resonance imaging (MRI) were performed in ten consecutive patients with proven mutations of the succinate dehydrogenase subunit D ( SDHD) gene predisposing to the development of glomus tumours and other paragangliomas. (18)F-DOPA PET and MRI were performed according to standard protocols. Both methods were assessed under blinded conditions by two experienced specialists in nuclear medicine (PET) and diagnostic radiology (MRI). Afterwards the results were compared. A total of 15 lesions (four solitary and four multifocal tumours, the latter including 11 lesions) were detected by (18)F-DOPA PET. Under blinded conditions, (18)F-DOPA PET and MRI revealed full agreement in seven patients, partial agreement in two and complete disagreement in one. Eleven of the 15 presumed tumours diagnosed by (18)F-DOPA PET were confirmed by MRI. The correlation of (18)F-DOPA PET and MRI confirmed three further lesions previously only detected by PET. All of them were smaller than 1 cm and had the signal characteristics of lymph nodes. For one small lesion diagnosed by PET, no morphological MRI correlate could be found even retrospectively. No tumour was detected by MRI that was negative on (18)F-DOPA PET. All tumours diagnosed by MRI showed a hyperintense signal on T2-weighted images and a distinct enhancement of contrast medium on T1-weighted images. The mean tumour size was 1.5+/-0.5 cm. (18)F-DOPA PET seems to be a highly sensitive metabolic imaging procedure for the detection of glomus tumours and may have potential as a screening method for glomus tumours in patients with SDHD gene mutations.

Pheochromocytomas and ganglioneuromas in the aging rats: morphological and immunohistochemical characterization

We investigated, morphologically and immunohistochemically, 74 medullary adrenal tumors, including 64 pheochromocytomas (14 malignant and 50 benign), 9 ganglioneuromas, and 1 malignant schwannoma. The tumors were detected in 2-year-old Wistar and Sprague-Dawley rats from carcinogenicity studies. Morphologically, benign pheochromocytomas were characterized by monomorphic, small, basophilic cells with almost absence of mitoses. Malignant pheochromocytomas presented a low grade of pleomorphism, higher rate of mitoses, necrosis, infiltrative growth and in 1 case metastases in the lung. Ganglioneuromas were characterized by ganglion and neuron-like cells embedded in an eosinophilic matrix containing neurites, Schwann cells, and scant fibrovascular elements. All pheochromocytomas were strongly immunoreactive for tyrosine hydroxylase (TH), the rate-limiting enzyme in catecholamine synthesis. Subpopulations of chromaffin cells expressed chromogranin A (CGA) positivity. Matrix and Schwann cells were positive for S-100 and for glial fibrillary acidic protein (GFAP). In focal areas of the tumors, ganglion cells and axons were positive for neurofilament proteins (NFP) and synaptophysin. Ganglion cells exhibited peripherin and beta-tubulin. Proliferative activity of the tumors was assessed by immunostaining the endogenous cell proliferation associated-antigen Ki-67 and the proliferating cell nuclear antigen (PCNA). As expected, cell proliferation indices were much higher in malignant pheochromocytomas than in benign, yet ganglioneuromas remained immunonegative. Considering that Ki-67 antigen is more specific for cell proliferation, it should be regarded as marker of choice for supporting the differential diagnosis between benign and malignant pheochromocytomas.

Glomus faciale, glomus jugulare, glomus tympanicum, glomus vagale, carotid body tumors, and simulating lesions. Role of MR imaging

In summary, MR imaging characteristics of a case of paraganglioma of the facial nerve are reported. The relationship of paragangliomas and the chromaffin system have been discussed. There are many reports of cases of synchronous paragangliomas and pheochromocytomas. These reports, along with simultaneous involvement in familial MEN syndromes, and the common embrylogic origin (neural crest) and similar histopathologic relationships between paragangliomas and pheochromocytoma, all support the fact that they are part of the chromaffin system.

Class III beta-tubulin isotype (beta III) in the adrenal medulla: I. Localization in the developing human adrenal medulla

BACKGROUND

The class III beta-tubulin isotype (beta III) is present in neurons of the central and peripheral nervous systems at the earliest stages of morphological differentiation (Easter et al., J Neurosci 13:285-299, 1993; Katsetos et al., J Neuropathol Exp Neurol 52:655-666, 1993). The localization of this protein by immunohistochemistry in the different cell types of the developing human adrenal medulla is described.

METHODS

A mouse monoclonal antibody, TuJ1, was used to localize beta III in formalin-fixed, paraffin-embedded sections from 18 human fetal and adult adrenal glands. Tissue sections were also studied with rabbit antisera recognizing either S-100 protein or glial fibrillary acidic protein (GFAP).

RESULTS

In the developing human adrenal medulla, beta III immunoreactivity was maximal in migrating sympathoadrenal neuroblasts/immature neurons through the end of the second trimester. Clusters of beta III-positive migrating cells, focally forming Homer Wright rosettes, could be identified in a gradient of adrenocortical invasion, i.e., through the permanent cortex and within sinusoids of the fetal cortex en route to the medulla. Outside the adrenal gland, strong beta III staining was observed in peripheral nerve bundles, sympathetic ganglia, and paraganglia at various developmental stages. In adrenal glands from 23 weeks of gestation on, and throughout adult life, all ganglion cells were beta III immunoreactive. In contrast, not all chromaffin cells exhibited beta III staining, but when present, the staining was finely granular. Sustentacular and satellite cells, adrenocortical cells and other mesenchymal elements were betaIII-negative. In sections of fetal and adult adrenal glands, S-100 protein had a sustentacular localization. No GFAP staining was present in sustentacular cells from either fetal or adult adrenals.

CONCLUSIONS

In the developing human adrenal medulla, there is a peak of beta III expression during the active wave of migration of sympathetic neuroblasts. In the mature medulla, beta III is invariably present in adrenergic neurons. However, not all chromaffin-like cells express beta III, suggesting that the presence or absence of this protein identifies two subpopulations of chromaffin cells.

Class III beta-tubulin isotype (beta III) in the adrenal medulla: II. Localization in primary human pheochromocytomas

BACKGROUND

The Class III beta-tubulin isotype (beta III) is expressed specifically in central and peripheral nervous system neurons at various stages of neuronal differentiation. We have shown previously that beta III is expressed in a differentiation-dependent manner in human neuroblastomas arising in the adrenal medulla and sympathetic chains (Katsetos et al., Clin Neuropathol 13:241-255, 1994). The neuronal distribution of beta III in the developing and mature human adrenal medullae is detailed in the companion article (Katsetos et al., 1998A).

METHODS

We have compared the localization of the neuronal beta III to S-100 protein, a sustentacular cell marker, in 14 formalin-fixed, paraffin-embedded primary human pheochromocytomas of the adrenal medulla and 14 adrenocortical tumors (adenomas and carcinomas).

RESULTS

In pheochromocytomas, beta III staining was present in all tumors, but the number of stained cells varied in the two neural neoplastic phenotypes. Although the majority of chromaffin-like cells were beta III-positive, there was a lack of beta III in one-third of the tumor cells. Compared to chromaffin-like phenotypes, neuronal (ganglion-like cells) were invariably beta III-positive. Stromal sustentacular cells, stromal fibroblasts, and tumor blood vessels were beta III-negative. Sustentacular cells in pheochromocytomas were S-100 protein-positive, but beta III-negative. Primary adrenocortical tumors were beta III-negative with the exception of rare beta III-positive cells demonstrated in one case.

CONCLUSIONS

The distribution of beta III in human pheochromocytomas of the adrenal gland is differentiation-dependent, closely recapitulating chromaffin cell and neuronal phenotypes of the normal adrenal medulla. Our findings indicate that beta III may be used as one of the adjuvant neural markers in the differential diagnosis of adrenal tumors, i.e., pheochromocytoma versus adrenocortical carcinoma. The occurrence of rare beta III-positive cells in cortical carcinomas is exceptional and probably represents the acquisition of a divergent neuroendocrine phenotype. The significance of the latter is unclear, although it may constitute a marker for malignancy.

Retinoic acid-enhanced invasion through reconstituted basement membrane by human SK-N-SH neuroblastoma cells involves membrane-associated tissue-type plasminogen activator

Al-trans retinoic acid (RA) enhanced human, S-type, SK-N-SH neuroblastoma cell invasion of reconstituted basement membrane in vitro but did not induce terminal differentiation of this cell line. In contrast to basal invasion, which was urokinase (uPA)- and plasmin-dependent, RA-enhanced invasion was dependent on tissue-type plasminogen activator (t-PA) and plasmin activity. Neither basal nor RA-enhanced invasion involved TIMP-2 inhibitable metalloproteinases. Enhanced invasion was associated with the induction of t-PA expression, increased expression of the putative t-PA receptor amphoterin, increased association of t-PA with cell membranes and increased net membrane-associated PA activity. Enhanced invasion was not associated with significant changes in the expression of uPA or its membrane receptor UPAR; plasminogen activator inhibitors PAI-1 and PAI-2; metalloproteinases MMP-1, MMP-2, MMP-3, MMP-9 and membrane type MMP1; or tissue inhibitors of metalloproteinases TIMP-1 and TIMP-2. RA stimulated the association of t-PA with the external cell membrane surface, which could be inhibited by heparin sulphate but not by mannose sugars or chelators of divalent cations, consistent with a role for amphoterin. Our data indicate that RA can promote the malignant behavior of S-type neuroblastoma cells refractory to RA-mediated terminal differentiation by enhancing their basement membrane invasive capacity. We suggest that this results from the action of a novel, RA-regulated mechanism involving stimulation of t-PA expression and its association with the cell membrane leading to increased PA-dependent matrix degradation.

Retinoic acid stimulates alpha-CAMKII gene expression in PC12 cells at a distinct transcription initiation site

The promoter region of the alpha-subunit of the calcium/calmodulin-dependent protein kinase II (alpha-CaMKII) gene was inserted into a beta-galactosidase (beta-gal) reporter plasmid, and beta-gal activities were examined in neuroblastoma (NB2a) and pheochromocytoma (PC12) cells after transient or stable transfections. The alpha-CaMKII promoter was 12- to 45-fold more active in NB2a compared with PC12 cells after transient or stable transfections. All-trans retinoic acid (RA) stimulated reporter gene expression at both protein and mRNA levels in transfected PC12 cells. RA increased the level of endogenous alpha-CaMKII mRNA in untransfected PC12 cells by 4.4-fold. The transcription initiation site(s) (TIS) of the alpha-CaMKII gene in PC12 cells and rat brain was examined by RNase protection assays (RPA) and reverse transcriptase PCRs. The TIS for the alpha-CaMKII/beta-gal reporter gene in transfected PC12 cells was indistinguishable from the TIS+1 in rat hippocampus. In contrast, the only detectable TIS for the alpha-CaMKII gene in untransfected PC12 cells was located near the ATG translation start codon, 147 nucleotides 3' to TIS+1 in hippocampus. This unusual TIS was also the predominant TIS in rat cerebellum. These results suggest that the alpha-CaMKII promoter may contain sequences that respond directly or indirectly to RA. In addition, the unusual TIS of the alpha-CaMKII gene in PC12 cells and rat cerebellum may contribute to the very low expression of this gene compared with that in hippocampus.

Carotid body tumor associated with hyperparathyroidism

Hyperparathyroidism in association with carotid body tumor is a rare combination. A common embryologic cellular origin was postulated previously to explain this unusual occurrence. We report a case of left carotid body tumor and left inferior parathyroid adenoma. We believe this to be the sixth reported case in the literature with this combination.

Pathology of APUDomas

The pathology of APUDomas involves two main areas. The first is the biochemical aspects of these tumours and the use of biochemical tests to investigate a patient suspected of having an APUDoma, and the other is the histopathology of these tumours. This review is devoted to the histopathological considerations.

Physiology of the APUD system

The characteristic biochemical pathway of the APUDoma cell, namely amine precursor uptake and decarboxylation, are illustrated by the examples of serotonin and catecholamine metabolism. Increasing understanding of the origins of APUDomas as well as the biochemistry and physiology of the hormones they produce, has led to improved methods of detection, imaging and treatment of afflicted patients.

Neuroectodermal tumors of the peripheral and the central nervous system share neuroendocrine N-CAM-related antigens with small cell lung carcinomas

The current study describes the presence of neuroendocrine antigens of peripheral and central neural tumors using eight monoclonal antibodies raised to small cell lung carcinoma (SCLC), which recognize "neural/neuroendocrine" or "neural" antigens, as defined by their reaction pattern in normal tissues and tumors. At least five of them recognize different epitopes of the neural cell adhesion molecule (N-CAM). It was found that all of 12 neuroblastomas, 2 ganglioneuroblastomas and 4 ganglioneuromas as well as 23 central primitive neuroectodermal tumors, 13 astrocytomas and 4 ependymomas share "neural/neuroendocrine" antigens (as defined by the anti-N-CAM antibodies Moc-1, -21, -32, -52 and -191) with SCLC. The "neural/neuroendocrine" antigen defined by Moc-171 was also found in all peripheral tumors, but only in further differentiated central tumors. Non-N-CAM related "neural" antigens (as defined by Moc-51 and -172) were found only in better-differentiated peripheral and central tumors, but they could be demonstrated in all three medulloblastoma cell lines studied. In addition, the antigen defined by Moc-51 was demonstrated in an immunoblot of a neuroblastoma cell line. Antibodies recognizing "epithelial" antigens of SCLC and other epithelia and their tumors (Moc-31 and -181) were non-reactive. It was concluded that these findings give further support for a relation between neural and neuroendocrine tumors and that some of the antibodies may be useful for the detection of differentiation in neural tumors. Antibodies with an "epithelial" recognition pattern may serve to distinguish neural from neuroendocrine tumors.

Malignant neuroendocrine tumor presenting in the mandible

The carotid body, jugulotympanic, vagal, and laryngeal paragangliomas are the most common paragangliomas respectively within the head and neck, although unusual examples in other sites have been described. Among these are several references in the literature to a mandibular or "alveolar body" paraganglioma, even though such an entity does not appear to have been adequately documented. This report describes a case which presented as an extensive osteoblastic tumor involving the mandible and which radiographically appeared as a typical osteosarcoma. However, the immunohistochemical and electron microscopic features were of a neuroendocrine tumor and the histologic pattern suggested a paraganglioma. The tumor was nonfunctional and an extensive search failed to reveal any further lesions. Eight months after resection of the lesion, metastatic deposits appeared within the left iliac crest and lumbar vertebra. The origin of this tumor is discussed.

Neurofilament and chromogranin expression in normal and neoplastic neuroendocrine cells of the human gastrointestinal tract and pancreas

To differentiate neuroendocrine (NE) neoplasms arising at different levels of the gut and pancreas, the authors studied the expression of neurofilament (NF) proteins and chromogranin (CR) in normal and neoplastic NE cells of the human gastrointestinal tract (GIT) (14 ileal/jejunal carcinoids, six appendiceal carcinoids, 11 rectal carcinoids) and pancreas (23 islet cell tumors). Among pancreatic islet cell tumors, those with middle molecular weight (NF-M)-positive cells were more abundant than those with high molecular weight (NF-H)-positive cells; nearly all of these tumors expressed CR. Although NF-M was abundantly expressed in greater than 50% of tumor cells in a subset of these tumors, only one of these tumors exhibited diffuse immunoreactivity with NF-H. Among rectal carcinoid tumors, NF-M and NF-H-positive cells were present in approximately the same number of tumors, yet only diffuse immunoreactivity to NF-H could be detected. Chromogranin immunoreactivity in greater than 50% of tumor cells was present in 74% of islet cell tumors, 93% of ileojejunal carcinoids, and 83% of appendiceal carcinoids, but only in a minority of rectal carcinoids (36%). Although ileojejunal carcinoid tumors rarely expressed NF-M and did not express NF-H, diffuse immunoreactivity with CR was present in nearly all of these tumors. None of the appendiceal carcinoid tumors expressed NF-M or NF-H, yet all of these tumors demonstrated immunoreactivity with CR. Neurofilament immunoreactivity was not detected in normal GIT and pancreatic NE cells, whereas CR immunoreactivity was always present. These results suggest that for NE neoplasms of the GIT and pancreas the differential expression of NF subtypes appears to be related to tumor site; and CR is a marker of most GIT and pancreatic NE neoplasms although NF may discriminate subtypes of GIT and pancreatic NE tumors. Neurofilament subtyping may be useful in the evaluation of the origin of NE tumors presenting as metastatic lesions.

A novel type of human alpha-amylase produced in lung carcinoid tumor

A novel type of alpha-amylase was detected in a lung carcinoid tissue after surveying the cDNA library constructed from this tumor mRNA. Nucleotide sequence analysis showed that the amylase expressed in this carcinoid tumor has 13 and 6 amino acid substitutions when compared with salivary amylase (Amy1) and pancreatic amylase (Amy2), respectively. The nucleotide sequence homologies of cDNAs between this carcinoid amylase and amy1, amy2 are 97.5% and 98.2%, respectively. The nucleotide sequence comparison strongly suggests that this new amylase is the product of the amy3 gene that has been detected in human genome [Emi et al., Gene 62 (1988) 229-235]

The dispersed neuroendocrine cells: the structure, function, regulation and effects of xenobiotics on this system

Cells which express morphological and functional markers originally described in neurons and neural crest-derived endocrine cells are now known to originate from both ectodermal and endodermal progenitors. These cells are organized to secrete peptides, amines, and other regulatory products in response to neurogenic or chemical stimulation. Individual products may function in endocrine, paracrine, neurotransmitter, or neuromodulatory roles. Multiple products are often produced by individual cells and stored in the same secretory granules. The hormonal profiles of particular types of neuroendocrine cells can, to varying degrees, be changed by environmental signals during development or in adult life. These changes are caused both by transcriptional and post-transcriptional mechanisms. Hormonal profiles are also altered during the development and progression of neoplasia. Signals which stimulate hormone secretion produce a number of ancillary effects, including activation and induction of enzymes which replenish hormone stores, activation of cellular oncogenes, and stimulation of cell proliferation. The effects of environmental signals on neuroendocrine cells are mediated by intracellular transduction pathways which involve cyclic AMP, phosphatidylinositol, calcium, and receptor protein kinase activity. These effects can be potentiated, inhibited, or qualitatively altered by exogenous agents.

Iodine-131 MIBG scintigraphy in small cell lung cancer

There is a well documented relationship between small cell carcinoma of the lung and the amine precursor uptake and decarboxylation system of endocrine cells (APUD). We attempted to exploit this association by employing the unique radiopharmaceutical, 131I-MIBG, which is recognized and taken up by the APUD system to monitor disease activity in patients with small cell carcinoma of the lung. A total of eight patients with biopsy proven, metastatic small cell carcinoma of the lung were studied. 131I-MIBG was synthesized in our laboratory by reacting metaiodobenzylamine hydrochloride with cyanamide with subsequent solid phase radioiodination. A dose of 0.5 mCi radiopharmaceutical was injected and images obtained on a large field of view gamma camera with a high energy parallel hole collimator at 2, 24, and either 48 or 72 h. Images were compared with known focal areas of metastatic disease demonstrable on computed tomographic scan, chest roentgenogram or bone scan. We were unable to detect reproducible correlations between the images produced by conventional radiographic techniques and the images produced by our radiopharmaceutical. We conclude that this agent will probably not be useful for localization of metastatic small cell lung carcinoma.

Carcinoid tumor with intradural spinal metastases

A case of spinal intradural metastasis from a carcinoid tumor is reported. The case is of interest due to the rarity of central nervous system involvement by these tumors and the long latency period of the patient's presentation.

Intracranial catecholamine secreting paragangliomas

Three intracranial catecholamine-secreting paragangliomas are described. They involved a glomus jugulare, a sphenopalatine ganglion and the clivus and upper cervical spine respectively. The extent of the tumours was shown by CT and MRI. They were all highly vascular with a substantial blood supply from systemic arteries which was subjected to particulate embolisation, followed in two cases by surgery. The importance of studying any tumour which could possibly be a paraganglioma for hormonal and, especially, for catecholamine secretion prior to any invasive procedure, including angiography and embolisation, is emphasised: all such procedures should be covered with catecholamine blocking agents and, in addition, carefully monitored with resuscitation facilities immediately available.

Radiologic manifestations of the syndrome of neurocrest and colonic tumors

This report describes the radiologic findings in the recently described syndrome of multiple colonic polyps and malignant tumors of neurocrest origin. One patient had multiple endocrine neoplasia syndrome type 11B with malignant medullary thyroid carcinoma, another had malignant pheochromocytoma, and the third had malignant carcinoid tumor. All patients had multiple colonic tubular or tubulovillous adenomas. In 2 patients, there were 8 sessile or pedunculated polyps distributed throughout the colon. In the patient with multiple endocrine neoplasia syndrome type 11B, the colon was carpeted with small polyps, 2-6 mm in size.

Medullary-thyroid-carcinoma imaging in an animal model: use of radiolabeled anticalcitonin F(ab')2 and meta-iodobenzylguanidine

Radiolabeled anti-calcitonin (CT) immunoglobulin fragments (131I-anti-CT F(ab')2) and meta-iodobenzylguanidine (131I-mIBG) were injected into nude mice with a transplanted medullary thyroid carcinoma (MCT). 131I-Anti-CT F(ab')2 proved to be unsuitable for MCT scintigraphic imaging. However, a high mIBG uptake was observed in MCTs, but not in control tumors (mesothelioma). The uptake of mIBG was not modified by the presence of reserpine or pentagastrine. These results are discussed, and it is suggested that mIBG could be an APUD-system marker.

Immunocytochemical staining of cytocentrifuge prepared cultured cells: nonspecific staining and its elimination

In an attempt to localize hormones in cytocentrifuge-prepared cultured cells of small cell carcinoma of the lung (SCCL), various modifications of the immunoperoxidase (PAP) procedure (Sternberger, 1979) were tested. When using glutaraldehyde, formaldehyde, or p-benzoquinone fixation (Pearse & Polak, 1975) and rabbit antibodies in primary or bridging steps of the PAP procedure, nonspecific staining (false positives) could be elicited with the majority of rabbit antibodies tested, but not with antibodies from other animal sources. This problem could be eliminated by fixation of cells either with formalin-acetone (Mason et al., 1975) or, when using antibodies from a source other than rabbit, glutaraldehyde. It was not possible to localize ACTH in DMS-79, a human SCCL line known to produce this hormone. However, calcitonin was localized in the calcitonin-producing SCCL line DMS-53. Failure to localize ACTH in DMS-79 may be due to the lower levels of this hormone in DMS-79, as compared to the levels of calcitonin in DMS-53. This study emphasizes the importance of proper controls before concluding successful localization in a given immunocytochemical preparation of cultured cells.

Bronchial carcinoid cells contain neural-type intermediate filaments

Monospecific antibodies and indirect immunofluorescent microscopic examination, combined with immunochemical analysis, were used to examine intermediate filaments in four cases of bronchial carcinoid tumors. The results show that carcinoid cells express intermediate filaments of neural type (neurofilaments) but are negative for intermediate filaments of mesenchymal type (vimentin), epithelial type (keratin), muscle type (desmin), and glial type (glial fibrillary acidic protein). Since the expression of intermediate filaments shows a high degree of tissue specificity, the results suggest either derivation of bronchial carcinoid cells from maternal cells displaying neural characteristics or from cells with the capacity to acquire neural properties on neoplastic growth. It is also suggested that antineurofilament antibodies can be used as a useful aid in differential diagnosis of bronchial carcinoids from other pulmonary tumors.

Metastatic islet cell tumor in von Hippel-Lindau disease

A 56-year-old woman with many unusual manifestations of von Hippel-Lindau syndrome is described. In addition to retinal hemangioblastomas, pheochromocytoma, renal cell carcinoma, and multiple organ cysts, she had a cerebellar astrocytoma, pancreatic exocrine insufficiency, diabetes mellitus, thyrotoxicosis, and a metastatic calcitonin-secreting islet cell carcinoma. This case report documents the first example of a metastatic islet cell tumor in a patient with von Hippel-Lindau disease. The possible relationship between this disorder, the other neurocutaneous syndromes, and the multiple endocrine neoplasia syndromes is discussed.

Hypothalamic polar spongioblastoma associated with the diencephalic syndrome. Ultrastructural demonstration of a neuro-endocrine organization

A tumor was resected from the third ventricle of a four years and eleven month old girl with the diencephalic syndrome. By light microscopy, it was diagnosed as a polar spongioblastoma . Its ultrastructural study was undertaken and the features were found to be distinctive and previously unreported. The organization of the neoplasm was similar to that of the hypothalamic neuro-endocrine systems: Cellular perivascular arrangement with intra-cytoplasmic microtubules and membrane bound dense-core granules.

Presence of fibroblast-type intermediate filaments (vimentin) and absence of neurofilaments in pigmented nevi and malignant melanomas

The cytoskeletal intermediate filaments of pigmented nevi and malignant melanomas (nine cases of each) were evaluated using monospecific antibodies against intermediate filament proteins and immunofluorescence microscopy. Both pigmented nevi and cutaneous malignant melanomas showed only vimentin-type intermediate filaments, but not keratin, neurofilaments, desmin or glial fibrillary acidic protein. Thus, nevi and melanomas do not show neural characteristics in the cytoskeletal intermediate filament pattern although they appear to show other neural markers. Vimentin - content in melanomas versus keratin - content in carcinomas may be used as a differential diagnostic feature.

Therapy of malignant APUD cell tumors. Effectiveness of DTIC

Eleven patients with malignant APUD tumors, five islet cell carcinomas, five carcinoid tumors and one medullary carcinoma of the thyroid were treated with DTIC. Nine of 11 patients benefitted from treatment. A literature review revealed that other APUD tumors responded when treated with DTIC. DTIC is a useful agent for treatment of malignant APUDomas, and may be the drug of choice for islet cell carcinoma of the pancreas.

Chemodectoma of the cheek. A case report

The first case of a chemodectoma of the cheek is presented and the histopathology reviewed. Chemodectomas of the head and neck can be difficult to diagnose, with angiography remaining the single most useful aid to determining both location and diagnosis. Surgery is the treatment of choice, and prognosis depends not only on the extent of the tumor but also its predilection for malignant behavior.

Use of isolated chromaffin cells to study basic release mechanisms

An account is given of the authors' work with isolated adrenal chromaffin cells to study the synthesis, storage and release of catecholamines and of a number of neuropeptides endogenous to the adrenal medulla. A review of other studies in the literature with the isolated chromaffin cell system is included. It is seen that the isolated chromaffin cells are a convenient in vitro system well-suited to studies of basic release mechanisms. The isolated adrenal chromaffin cells maintain high levels of catecholamines and opiates and release them by exocytosis. The cells have both nicotinic and muscarinic receptors but only the nicotinic are involved in the agonist-evoked release of catecholamines (EC50 nicotine 5 X 10(-6) M: ACh 5 X 10(-5) M). The cells can synthesize AChE and selectively release the 10S molecular form by a mechanism different from exocytosis. Substance P (SP) modulates the secretion of catecholamines and ATP evoked by ACh or nicotine but not that evoked by K+ or veratridine. SP appears to interact with the nicotinic receptor-ionophore complex to regulate Na+ entry. SP receptors on the chromaffin cells show similar structural requirements to SP receptors in other SP responsive tissues. Binding studies on isolated chromaffin cell membranes with [4-3H-Phe]SP have shown specific binding in the nM range. In addition, at high concentrations of ACh, SP protects against nicotinic receptor desensitization. Since SP is contained in the splanchnic nerve terminals that innervate the medulla, the demonstration of SP action and SP receptors on the chromaffin cells suggests a physiological role for SP in the regulation of secretion from the adrenal medulla. Somatostatin (SS) and a number of SS analogues also inhibit release, but are approximately 15-fold less potent than SP. Leu- and Met-enkephalin, which are co-stored with adrenaline in the bovine adrenal medullary cells produce a non-specific inhibition of the nicotine-evoked release of CA, but enhance the basal release of endogenous catecholamines by a mechanism that is Ca2+-dependent, stereospecific and reversible by naloxone and naltrexone. The implication of these peptide-amine interactions for physiological processes regulating homeostasis in the adrenal are discussed.

5-hydroxytryptamine and cholera secretion. Physiological and pharmacological studies in cats and rats

The intestinal secretion evoked by close intra-arterial infusion of 5-hydroxytryptamine (5-HT) in cats was inhibited by tetrodotoxin, a drug abolishing action potentials. Furthermore, the intestinal secretion produced by placing a 2-mM 5-HT solution in the intestinal lumen of rats was inhibited by hexamethonium, a ganglionic receptor-blocking agent. These observations strongly indicate that 5-HT-induced secretion is, at least in part, neurally mediated. It was also shown that 5-HT receptors are involved in the pathophysiology of choleraic secretion, since the secretion was inhibited by making the experimental animal tachyphylactic against 5-HT. No effects of 5-HT tachyphylaxis were noted on fluid transport in normal intestines. The results are discussed in relation to a new hypothesis for the pathophysiology of cholera secretion.

Localization of carcinoids and pheochromocytomas with vein catheterization and amine determination

Selective catheterization of hepatic, intestinal and adrenal veins with blood sampling for serotonin and catecholamine determination was evaluated regarding its use in the diagnosis, location and characterization of carcinoids and pheochromocytomas. Catheterization of intestinal veins via the transhepatic route and of the adrenal veins via the femoral and caval veins was performed in 49 patients without major complications. High pressure liquid chromatography with electrochemical detection was used to quantitate norepinephrine and epinephrine in plasma and serotonin in plasma and whole blood. Serotonin in plasma was also determined by an enzymatic procedure. In 30 patients with suspected or verified carcinoid tumors concentration of serotonin in tumor-draining veins was clearly elevated in all patients but one. In this patient, who previously had been treated with temporary liver dearterialization, the serotonin concentration in the hepatic vein was within the normal range in spite of the existence of liver metastases. Hyperserotoninemia was registered in one patient without detectable carcinoid tumor cells. In three patients determination of norepinephrine and epinephrine in adrenal venous blood diagnosed a hyperplasia and tumors in the adrenal medulla. In these cases angiography and computed tomography were negative. Microscopic analyses revealed serotonin in all carcinoids and substance P-like immunoreactivity in a large percentage of these tumors. PP-like and glucagon-like immunoreactivity were observed in two endocrine pancreatic tumors. In normal adrenal medulla and in adrenal medullary tumor tissue catecholamine fluorescence and enkephalin-like immunoreactivity were demonstrated. In the two pheochromocytomas ACTH-like, somatostatin-like and calcitonin-like immunoreactivities were identified. The technique with determinations of plasma serotonin and catecholamines in combination with selective catheterization is a useful investigation for the diagnosis, location and follow-up of patients with carcinoids and pheochromocytomas.

Cushing's syndrome secondary to a neuroendocrine tumor: relapse after bilateral adrenalectomy

Bilateral adrenalectomy results in the removal of the site of glucocorticosteroid production thereby eliminating the signs and symptoms of Cushing's syndrome. A case is reported of a middle-aged man with Cushing's syndrome due to an ACTH-producing tumor. The patient initially responded to adrenalectomy but had a fatal relapse. Autopsy showed that the right adrenal bed containing remnants of adrenal tissue. An islet cell carcinoma of the pancreas was thought to be the primary tumor.

Hypercalcemia complicating small-cell carcinoma

Hypercalcemia is a common paraneoplastic syndrome complicating some varieties of lung cancer. It has rarely been reported with small-cell carcinoma of the lung. Seven cases of hypercalcemia complicating small-cell carcinoma of the lung are described; clinical features indicate that significant bone or bone marrow involvement is present in all cases. Parathormone assays were found to be generally in the normal range, though inappropriate for the levels of hypercalcemia.

Malignant Paraganglioma of the Carotid Body. Clinical, Morphologic, Histologic and Ultrastructural Findings in One Case

A case of clinically malignant right carotid glomus paraganglioma, with lymph nodes and pulmonary metastasis, is reported. Histological, histochemical and ultrastructural features of the tumor are discussed. The authors emphasize the relative rarity of malignant paragangliomas and the difficulty to determine the malignancy of the neoplasm only on the basis of the histological examination.

Ultrastructure of endocrine-like cells in lamina propria of human gastric mucosa

Endocrine cells of gastric and gut mucosa are commonly thought to be present only within mucosal glands. In a previous report, we described argyrophilic cells in the lamina propria in 40% of surgical gastric specimens, using light microscopy. All these patients had chronic gastritis. Argyrophilia, however, is a non-specific reaction which could occur in other than endocrine cells. The present study was undertaken to describe the ultrastructure of argyrophil cells in the lamina propria. In five patients with chronic gastritis, endoscopic biopsies were taken from the fundic, intermediate, and pyloric areas of the stomach. Single and/or clustered argyophil cells were seen by light microscopy in the lamina propria of the intermediate and pyloric areas. On electron-microscopy, these cells had the following characteristics of endocrine-like cells: they were characterised by numerous electron dense granules in the cytoplasm, 100-300 nm in diameter; the cytoplasm contained poorly-developed rough endoplasmic reticulum and well-developed smooth endoplasmic reticulum with occasional vesicles. Immunostaining gave negative results for various gastrointestinal hormones. These ultrastructural characteristics of lamina propria cells are similar to endocrine cells of the APUD series. We conclude that endocrine-like cells occur in the lamina propria of the human stomach in the presence of chronic gastritis.