Organoid Architecture Research Articles

Re-evaluation of the concept of basaloid follicular hamartoma associated with naevoid basal cell carcinoma syndrome: a morphological, immunohistochemical and molecular study

Naevoid basal cell carcinoma syndrome (NBCCS) is a rare genodermatosis caused by germline mutations in genes of the Sonic Hedgehog (SHH) pathway and is characterised by early onset of multiple basal cell carcinomas (BCCs). Although skin tumours with follicular differentiation, notably basaloid follicular hamartoma (BFH), have been reported in NBCCS, their relations with BCC are poorly defined. In this context, the aim of this study was to clarify morphological, immunohistochemical ​and molecular features of BFH arising in a context of NBCCS. A total of 140 skin tumours from NBCCS and 140 control BCC tumours were reviewed, blinded to clinical data and classified as BCC or BFH. The morphological characteristics of these two groups were then compared. Twenty cases were submitted for immunohistochemical and molecular analysis. Thirty-three tumours among the exploratory cohort were classified as BFH and were exclusively detected in NBCCS patients. Histopathological criteria that were significantly different from BCC were as follows: a small size (<1.5 mm), connection to a hair follicle, arborescent organoid architecture, lack of cytological atypia and infundibulocystic differentiation. Immunohistochemical analysis confirmed activation of the SHH pathway in these lesions. Targeted next-generation sequencing suggested that MYCN and GLI2/3 amplifications and TP53 mutations might be involved in progression of these follicular tumours to BCC. Our study confirms the high prevalence of BFH, representing up to 24% of skin tumours in NBCCS and potentially being BCC precursors.

Engineering In–vitro Microenvironments to Replicate Complex In vivo Conditions for Organoid Architecture

Engineering In–vitro Microenvironments to Replicate Complex In vivo Conditions for Organoid Architecture

147 Human Lung Organoids Predict Response to Carbon-Based Nanomaterials and Model Pulmonary Fibrosis

Abstract Advances in in-vitro culture systems have stimulated an interest in more reliable testing approaches that predict nanomaterial toxicity. Lung organoids are one example, and display functions consistent with their in-vivo counterparts. Organoids have been used in a variety of applications, but studies have yet to interrogate their suitability for nanomaterial testing. Here, we report the step-wise development of multilineage lung organoids, and validate their potential as tools for predicting pulmonary toxicity of carbon-based nanomaterials. After 50-days of differentiation, the lung organoids exhibited the six major proximal (goblet/basal/club/ciliated) and distal (AECI/II) epithelial cell types of the adult lung. Using microinjection, we developed an exposure model to exploit the airspace-like lumen of the organoids for cargo delivery. We compared the impact of small nanometric (50-950nm, sGO) and large micrometric (4-41µm, lGO) graphene oxide sheets, with multi-walled carbon nanotubes (1-20µm, MWCNT) on lung organoids after 1/7/28d exposure. Consistent with in-vivo data, sGO and lGO exhibited a transient interaction with the alveolar epithelium, and did not induce any histoarchitectural changes indicative of fibrosis. Organoids did however produce 2.5-fold more mucins in response to lGO than sGO exposure, suggesting that a thicker mucin barrier is required to prevent lGO-induced damage. In contrast, MWCNT caused detrimental effects on organoid architecture. Its persistent interaction with the alveolar epithelium led to a pro-fibrotic phenotype, where MWCNT caused AECII to undergo epithelial-mesenchymal transition. With further development, our model may reduce the need for rodent inhalation studies in the assessment of lung toxicity.

Secrete and Exude-Pancreatic Neuroendocrine Tumour

Pancreatic neuroendocrine tumour is derived from neuroendocrine cells of pancreas or hormone secreting cells within vicinity of pancreas and is categorized into indolent well differentiated neuroendocrine tumour (WDNET) and the aggressive, rapidly progressive poorly differentiated neuroendocrine carcinoma(PDNEC). Well differentiated neuroendocrine tumour (WDNET) demonstrates inactivation of MEN1, genetic mutation or loss of DAXX / ATRX, altered mTOR pathway, incrimination of PTEN, TSC2, PIK3CA genes with alteration of VHL. Poorly differentiated neuroendocrine carcinoma and mixed neuroendocrine / non neuroendocrine neoplasm delineates alterations within TP53, RB, KRAS, APC, BRAF or SMAD4 / DPC4 genes. Neuroendocrine tumour delineates an organoid architecture with solid nests, trabeculae, gyri, cords, festoons, ribbons, glandular, pseudoacinar or tubulo-acinar articulations. Miniature to intermediate tumour cells are permeated with eosinophilic, amphophilic, finely granular cytoplasm, centric, spherical to elliptical, uniform nuclei with finely stippled ‘salt and pepper’ nuclear chromatin, inconspicuous nucleoli and an abundant circumscribing vascular network. Pancreatic neuroendocrine tumour is immune reactive to CK8 / CK18, CAM 5.2, OSCAR, AE1 / AE3, synaptophysin, chromogranin A, INSM1, CD56, neuron specific enolase (NSE) or CD57. Pancreatic neuroendocrine tumour pancreas requires segregation from neoplasms such as acinar cell carcinoma, pancreatoblastoma, solid pseudo-papillary neoplasm, pancreatic ductal adenocarcinoma, paraganglioma, clear cell tumours as clear cell sarcoma, metastatic renal cell carcinoma, PEComa or solid variant of serous cystadenoma. Comprehensive surgical eradication is recommended for treating well differentiated neuroendocrine tumour. Poorly differentiated neuroendocrine tumour is appropriately treated with platinum based chemotherapy.

Neuroendocrine Tumor of the Appendix (A Case Report)

Neuroendocrine tumours (NETs) are characterised by their ability to secrete hormones. There is a wide variety of NETs that can develop in any organ of the digestive system. NETs of the appendix are rare with an estimated incidence of 0.15 to 06 cases/year per 100,000 people and are often seen in young adults with a male predominance. Most NETs of the appendix are asymptomatic and usually discovered incidentally during appendectomy. Treatment is by surgical removal of the tumour to a healthy margin in accordance with the principles of carcinology. We report on a case of a 24-year-old female patient. She was admitted with generalized abdominal pain originating in the right iliac fossa with a B.P. of 0 and a fever of 38°C. The abdominal and pelvic CT scan showed acute appendicitis with a discrete agglutination of the loop around the appendix and an effusion of the right iliac fossa and pelvis of medium abundance. The biological work-up showed a hyperleukocytosis with a predominance of neutrophils. The patient underwent ileo-caecal resection, ileo-colostomy in double gun barrel after an exploration which revealed a mass of appendicular cystic appearance "suspicion of appendicular mucocele?" with a purulent peritoneal effusion and false membranes in the inter-anses. Pathological examination showed a proliferation of organoid architecture suggestive of a neuroendocrine tumour measuring 4 mm in length.

Imaging three-dimensional brain organoid architecture from meso- to nanoscale across development.

Organoids are stem cell-derived three-dimensional cultures offering a new avenue to model human development and disease. Brain organoids allow the study of various aspects of human brain development in the finest details in vitro in a tissue-like context. However, spatial relationships of subcellular structures, such as synaptic contacts between distant neurons, are hardly accessible by conventional light microscopy. This limitation can be overcome by systems that quickly image the entire organoid in three dimensions and in super-resolution. To that end we have developed a system combining tissue expansion and light-sheet fluorescence microscopy for imaging and quantifying diverse spatial parameters during organoid development. This technique enables zooming from a mesoscopic perspective into super-resolution within a single imaging session, thus revealing cellular and subcellular structural details in three spatial dimensions, including unequivocal delineation of mitotic cleavage planes as well as the alignment of pre- and postsynaptic proteins. We expect light-sheet fluorescence expansion microscopy to facilitate qualitative and quantitative assessment of organoids in developmental and disease-related studies.

The drug-induced phenotypic landscape of colorectal cancer organoids

Patient-derived organoids resemble the biology of tissues and tumors, enabling ex vivo modeling of human diseases. They have heterogeneous morphologies with unclear biological causes and relationship to treatment response. Here, we use high-throughput, image-based profiling to quantify phenotypes of over 5 million individual colorectal cancer organoids after treatment with >500 small molecules. Integration of data using multi-omics modeling identifies axes of morphological variation across organoids: Organoid size is linked to IGF1 receptor signaling, and cystic vs. solid organoid architecture is associated with LGR5 + stemness. Treatment-induced organoid morphology reflects organoid viability, drug mechanism of action, and is biologically interpretable. Inhibition of MEK leads to cystic reorganization of organoids and increases expression of LGR5, while inhibition of mTOR induces IGF1 receptor signaling. In conclusion, we identify shared axes of variation for colorectal cancer organoid morphology, their underlying biological mechanisms, and pharmacological interventions with the ability to move organoids along them.

Bisphenol A replacement chemicals, BPF and BPS, induce protumorigenic changes in human mammary gland organoid morphology and proteome

SignificanceBisphenol A (BPA), found in many plastic products, has weak estrogenic effects that can be harmful to human health. Thus, structurally related replacements-bisphenol S (BPS) and bisphenol F (BPF)-are coming into wider use with very few data about their biological activities. Here, we compared the effects of BPA, BPS, and BPF on human mammary organoids established from normal breast tissue. BPS disrupted organoid architecture and induced supernumerary branching. At a proteomic level, the bisphenols altered the abundance of common targets and those that were unique to each compound. The latter included proteins linked to tumor-promoting processes. These data highlighted the importance of testing the human health effects of replacements that are structurally related to chemicals of concern.

Single Organoids Droplet-Based Staining Method for High-End 3D Imaging of Mammary Organoids.

In the last decade, organoids became a tremendously popular technique in developmental and cancer biology for their high pathophysiological relevance to in vivo models with the advantage of easier manipulation, real-time observation, potential for high-throughput studies, and reduced ethical issues. Among other fundamental biological questions, mammary organoids have helped to reveal mechanisms of mammary epithelial morphogenesis, mammary stem cell potential, regulation of lineage specification, mechanisms of breast cancer invasion or resistance to therapy, and their regulation by stromal microenvironment. To exploit the potential of organoid technology to the fullest, together with optimal organoid culture protocols, visualization of organoid architecture and composition in high resolution in three dimensions (3D) is required. Whole-mount imaging of immunolabeled organoids enables preservation of the 3D cellular context, but conventional confocal microscopy of organoid cultures struggles with the large organoid sample size and relatively long distance from the objective to the organoid due to the 3D extracellular matrix (ECM) that surrounds the organoid. We have overcome these issues by physical separation of single organoids with their immediate stroma from the bulk ECM. Here we provide a detail protocol for the procedure, which entails single organoid collection and droplet-based staining and clearing to allow visualization of organoids in the greatest detail.

Clinicopathological Features of Primary Neuroendocrine Tumors of Gastrointestinal/Pancreatobiliary Tract With Emphasis on High-Grade (Grade 3) Well-Differentiated Neuroendocrine Tumors.

IntroductionThe two broad subcategories of neuroendocrine neoplasms (NENs) are well-differentiated neuroendocrine tumors (WDNETs) and poorly differentiated neuroendocrine carcinomas (PDNECs), based on tumor architecture and cytology. Grade 3 WDNETs are a subset of WDNETs that not only are high grade by mitotic activity or proliferative index but exhibit a well-differentiated histology. In this study, we evaluated the clinicopathological features of primary neuroendocrine tumors of the gastrointestinal (GI)/pancreatobiliary tract with emphasis on high-grade WDNETs, as it is a newly defined entity.MethodsWe conducted a retrospective observational study, including a total number of 122 cases of primary GI and pancreatobiliary tract NENs. Slides and blocks of all cases were retrieved from the departmental archives. Immunohistochemical stains including Ki67 were applied to selected tissue blocks of all cases. Tumors were then evaluated for their histological differentiation and tumor grade.ResultsOur results showed that the mean age of patients was 46.8 ± 17.1 years. Majority of the NENs were GI tract origin (86.9%). The most common site of tumor in gastroenteropancreatic tract was the small bowel (31.1%), followed by the stomach (26.2%). Ninety five percent of the tumors were WDNETs, of which the most common grade was G2. The mean Ki67 index was 15.8 ± 23.8. Grade 3 WDNETs were noted to have an older mean age than grades 1 and 2 WDNETs. Ten out of 102 (9.8%) WDNETs of GI tract were grade 3, compared with four out of 14 (28.6%) of pancreatobiliary tract. ConclusionIn this study, we found that high-grade (grade 3) WDNETs were more frequent in pancreatobiliary tract than GI tract. Moreover, high-grade WDNETs were associated with a higher mean age than low-grade (grade 1-2) WDNETs. It is extremely important to recognize this subset (high grade) of WDNETs and to distinguish it from PDNECs, as the latter are known to be associated with a worse overall survival. Despite high mitotic rate/proliferative index, high-grade WDNETs are characterized by organoid architecture and monomorphic cell population.

Abstract 1577: Gene expression studies using microgel embedded pancreatic cancer spheroids

Abstract Pancreatic ductal adenocarcinoma (PDAC) is known to be one of the deadliest cancers due to its late diagnosis and faster metastasis rate1. Thus, the time required to test the patient-derived cancer cells against different therapeutics becomes extremely crucial. Gene expression analysis using real-time PCR is vital, typically when designing patient-specific therapeutics. 2D tumor models do not represent the true picture of the tumor in vivo. In order to perform these gene expression studies, robust 3D cancer models are required2. The traditional techniques of generating cancer spheroids using U-bottom wells and hanging drop methods are effective but are limited by scalability as well as the limitations associated with the traditional organoid architecture. Gene expression studies of spheroids under different combinations of drug treatment thus requires many well defined and easy to handle spheroids. Here, we are trying to perform real-time PCR studies to access the gene expression changes on MIA PaCa-2 microgel based spheroids generated using co-axial droplet microfluidics with or without stromal cells. This 3D platform will enable gene expression studies in miniature co-culture tumor models. In addition, PCR and single-cell sequencing analyses will define the gene expression changes in the recently described conditionally reprogramed, patient-derived, primary PDAC cultures3. The establishment and analysis of this 3D model is fast, reproducible and can be easily scaled to enable high-throughput screening, thereby providing an opportunity to design patient-specific precision medicine. The research leading to these results received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement No 759959, ERC-StG “INTERCELLMED”).

Hyalinizing trabecular tumor of the thyroid gland and its significant diagnostic issue

BackgroundHyalinizing trabecular tumors (HTT) are rare follicular cell-derived tumors of the thyroid gland that are infrequently reported in otolaryngology literature. We present here an interesting case of HTT which provides the basis for review of this entity’s clinical characteristics, criteria useful in making the diagnosis, and any currently available therapeutic modalities.Case presentationA 70-year-old Caucasian female underwent a CT scan of her chest and was incidentally found to have a nodule within the right thyroid lobe. Gross examination of the excised thyroid lobe revealed a circumscribed and encapsulated lesion (tan / gritty in texture), confined to the gland. Histologic sections of the lesion revealed a circumscribed neoplasm with a trabecular and organoid architecture associated with abundant dystrophic calcification. Neoplastic cells showed a spindled morphology with clumped chromatin and ample eosinophilic cytoplasm.ConclusionsHistologically, HTT is a follicular cell-derived tumor composed of neoplastic cells arranged in a trabecular pattern with hyalinization and calcification of extracellular material. Distinguishing features of HTT include minimal cytologic atypia with a low nuclear: cytoplasmic ratio, cellular aggregates around hyalinized material, and nuclei with clumped chromatin and occasional grooves and/or pseudoinclusions. Though debated in the literature, the general consensus is that this tumor is a benign entity. It is our hope that additional clinical research will elicit awareness of these rare tumors.

A Carcinoid Tumor in the Urinary Bladder With Uncommon Clinicopathological Presentation

Carcinoid tumors usually originate from the enterochromaffin cells located in gastrointestinal tract and bronchopulmonary system. They may rarely arise in the urinary bladder, where this can be eventually miscued as any other commoner bladder neoplasms. The current study was conducted to connote an uncommon clinicopathological presentation by a carcinoid tumor in the urinary bladder. A 52-year-old male, who initially experienced obstructive urinary symptoms, underwent cystourethroscopy to remove a tumor in the urinary bladder. The tumor exhibited insular, trabecular, and organoid architecture on histology without any necrosis or mitosis, stained positively with chromogranin A, and thereby, confirmed the diagnosis of a pure carcinoid tumor. Carcinoid tumors rarely arise in the urinary bladder and other genitourinary organs. But, several other and relatively more common bladder neoplasms may often deceptively simulate it. This dilemma could be resolved easily with the application of proper immunohistochemistry (IHC) in neuroendocrine tumors.

426 Epithelial Cell Adhesion Molecule (EpCAM) regulates epithelial homeostasis via Rho-associated protein kinase (ROCK)

EpCAM (Epithelial Cell Adhesion Molecule) is a cell surface protein that is expressed by some normal epithelial cells and many carcinomas. EpCAM is not a classical adhesion molecule and it has been reported to modulate epithelial cell physiology via several mechanisms. Some patients with a congenital diarrheal syndrome termed congenital tufting enteropathy (CTE) have EpCAM mutations, and EpCAM knockout mice have a CTE-like phenotype, documenting the importance of EpCAM in intestinal epithelial cell (IEC) homeostasis. For this reason, we are studying primary IEC to understand EpCAM function in greater detail. IEC organoids can be readily propagated from mouse intestine and they recapitulate many facets of normal IEC development and physiology. Treatment of crypts from ROSA CreER EpCAMfl/fl mice with tamoxifen for the first 3 days of culture leads to loss of EpCAM expression and organoids that exhibit smaller sizes, lower forming efficiencies, and markedly reduced passaging efficiencies as compared with control organoids. Although cellular polarity is maintained and intercellular junctions are not strikingly abnormal in EpCAM-deficient organoids, organoid architecture is disorganized and epithelial integrity is lost. Effects of EpCAM loss are selectively attenuated in EpCAM-deficient organoids treated with Rho-associated protein kinase (ROCK) inhibitors and a myosin II inhibitor. Consistent with this, phosphorylation of targets that are downstream of ROCK, including myosin light chain II (Ser19 and Thr18/Ser19), is enhanced in EpCAM-deficient organoids. Fluorescence in situ hybridization experiments suggest that stem cell numbers are decreased in EpCAM-deficient organoids but Paneth cells, an important source of Wnt in vitro, are also abnormal. Similar results have been obtained after acute EpCAM deletion in intestines of ROSA CreER EpCAMfl/fl mice treated with tamoxifen for 3 days. We are in the process of determining if our results reflect regulation of ROCK by EpCAM in stem cells, Paneth cells or perhaps both cells, and elucidating the mechanism by which this occurs.

Pathways Involved in Formation of Mammary Organoid Architecture Have Keys to Understanding Drug Resistance and to Discovery of Druggable Targets.

Signals from the extracellular matrix (ECM) are received at the cell surface receptor, transmitted to the cytoskeletons, and transferred to the nucleus and chromatin for tissue- and context-specific gene expression. Cells, in return, modulate the cell shape and ECM, allowing for the maintenance of tissue homeostasis as well as for coevolution and adaptation to the environmental signals. We postulated the existence of dynamic and reciprocal interactions between the ECM and the nucleus more than three decades ago, but now these pathways have been proven experimentally thanks to the advances in imaging and cell/molecular biology techniques. In this review, we will introduce some of our recent work that has validated the critical roles of the three-dimensional (3D) tissue architecture in determining mammary biology, therapeutic response, and druggable targets. We describe a novel screen based on reversion of the malignant phenotype in 3D assays. We will also summarize our recent discoveries of the integration of feedback signaling for mammary acinar formation and phenotypic reversion of tumor cells in the LrECM. Lastly, we will introduce our exciting discovery of the physical linkages between the cell surface and cytofibers within a tunnel deep inside of the nucleus, enabling interaction with nuclear lamin and SUN proteins.

Ectopic secretion of GHRH by a pancreatic neuroendocrine tumor associated with an empty sella

Acromegaly is usually the result of a pituitary growth hormone cell-adenoma or is more rarely due to ectopic secretion of growth hormone releasing hormone (GHRH).We report the case of a 60-year-old woman with acromegaly due to a GH-RH-secreting pancreatic tumor. Laboratory evaluation confirmed the diagnosis of acromegaly. Magnetic resonance imaging revealed a partial empty sella with no signs of adenoma. Ultrasound sonography performed for abdominal pains showed a calcified large heterogeneous infrahepatic mass. Computed tomography scan discovered a heterogeneous pancreatic head mass with a diameter of 10 cm. Measurement of fasting plasma GHRH was performed showing a high concentration of 604 ng/L (normal 10–60). We therefore concluded that the acromegaly was caused by ectopic overproduction of GHRH likely due to the pancreatic tumor. The patient underwent a cephalic duodenopancreatectomy. Histology revealed a well-circumscribed tumor with organoid architecture. Immunohistochemistry demonstrated diffuse positivity for chromogranin A, neuronal specific enolase and synaptophysin and negative immunoreactivity for prolactin, GH and serotonin. These features were concordant with a well-differentiated neuroendocrine tumor of the pancreas. Surgical resection of this pancreatic tumor was followed by significant amelioration of acromegalic signs and normalization of GHRH and GH levels.

Primary Extrapulmonary Sugar Tumor (PEST): A Report of Four Cases

The cell of origin and direction of differentiation of the clear cell tumor of the lung (the so-called sugar tumor) remains enigmatic. Recognition of HMB-45 immunoreactivity and identification of melanosomes have suggested a relationship to angiomyolipoma of kidney or liver and lymphangiomyoma. This has given rise to the concept that clear cell tumors are neoplasms of so-called perivascular epithelioid cells—PEComas. Herein we report the existence of four similar tumors occurring in extrapulmonary sites, one of which had malignant features. The three benign tumors occurred in females ages 9, 20, and 40 years; two were located in the rectum and one in the vulva. The malignant tumor occurred in the inter-atrial cardiac septum of a 29-year-old man. Common histologic features were a richly vascular organoid architecture, tumor cells with clear to pale eosinophilic cytoplasm, abundant glycogen, and immunoreactivity for HMB 45, but not S100, multiple keratin, neuroendocrine, or muscle markers. Benign tumors demonstrated low mitotic activity, no necrosis, and good circumscription; the malignant tumor showed considerable mitotic activity, necrosis, and an infiltrative growth pattern. Ultrastructurally, glycogen was present, mitochondria were abundant, and membrane-bound lamellated bodies consistent with premelanosomes were present in two cases, and equivocal in one.Because these tumors have light microscopic, immunohistochemical, and electron microscopic features similar to pulmonary sugar tumors, we propose the name primary extrapulmonary sugar tumor (PEST) for them. Although most PEST's are probably benign, malignant forms appear to exist. These cases further support the concept of a family of systemic HMB-45 positive tumors that include sugar tumors, angiomyolipoma of kidney or liver, lymphangiomyomas, and clear-cell myomelanocytic tumors of the falciform ligament/ligamentum teres.

Large cell neuroendocrine carcinoma of the lung: a histologic and immunohistochemical study of 22 cases.

Large cell neuroendocrine carcinoma (LCNEC) of the lung is defined as a poorly differentiated and high-grade neuroendocrine tumor that is morphologically and biologically between atypical carcinoid and small cell lung carcinoma (SCLC). During a survey concerning bcl-2 protein expression in the subtypes of lung cancer, we noticed that two previously diagnosed non-SCLCs met the criteria for LCNEC. Because LCNEC is a newly recognized clinicopathologic entity and because all reported cases have been retrieved from the so-called "neuroendocrine tumor file," we suspected that LCNEC had been underdiagnosed. In the present study, we histologically reviewed 766 surgically resected lung cancers and were able to diagnose 22 (2.87%) LCNECs with the neuroendocrine features subsequently confirmed by immunostaining for multiple neuroendocrine markers. Each case stained positively for at least three general neuroendocrine markers, and 12 (54.5%) also were positive for neuroendocrine hormones. Histologically, most LCNECs showed a marked decrease in or a loss of organoid architecture and could be mistaken for poorly differentiated adenocarcinoma or squamous cell carcinoma. Because our LCNECs are the first to be identified by retrospective review of routinely diagnosed lung cancers, and 18 had been classified as non-SCLC, they may represent cases relatively difficult to diagnose. The present study shows that the most difficult diagnostic factor of LCNEC is the recognition of its light microscopic neuroendocrine features, and LCNEC must be distinguished not only from atypical carcinoid or SCLC, but also from common non-SCLC. Histologically, when an organoid architecture is subtle or absent, the rosettelike structure becomes the best marker for the recognition of neuroendocrine differentiation. Clinically, the prognosis for our LCNECs was significantly worse than that for stage-comparable non-SCLCs (p = 0.046).

Matrix Cells Dissociated from the Mouse Forebrain Vesicle Reaggregate to Form Neural Tube-like Organoid Structures in vitro.

An in vitro study employing dissociated matrix cells obtained from the rostral part of mouse neural tube or forebrain vesicle was done in an attempt to elucidate their cellular characteristics. We found a reaggregate formation with an organoid architecture. The organization of the reaggregate was studied by transmission as well as scanning electron microscopy, and by immunocytochemistry. After three days in a stationary culture, dissociated matrix cells formed a spherical, organoid reaggregate having a central lumen. The size of the reaggregate varied from approximately 100μm to 200μm. The transmission electron microscopy revealed that the reaggregate wall is composed of two types of cells; one has an electron-lucent cytoplasm with few organelles except for polysomes, whereas the other contains an electron-dense cytoplasm with many microtubules and mitochondria. The latter type of cell was located in the marginal portion of the wall intermingled with a large number of cellular processes. These cells were immunostained with anti-neurofilament antibodies and regarded as neuroblasts. The luminal surface was composed predominantly of the former cell type showing well-developed junctional complexes in between them and having cilia on its luminal side. Mitotic figures were frequently demonstrable adjacent to the lumen.

Carcinoid Tumor of the Larynx

Typical carcinoid neoplasms of the larynx are extremely rare tumors. The total number of known and documented cases is likely no more than 13. The neoplasm mainly affects males at an average age of 58 years and appears grossly as a polypoid or sessile submucosal nodule with an average 1.8 cm in size. Their predominant location is the supraglottis with the arytenoid and the aryepiglottic fold being the most frequent sites. Histologically, they are characterized by organoid architecture, uniform cellular features and lack of pleomorphism, necrosis and mitosis. Typical laryngeal carcinoids are less aggressive than their atypical counterparts but late distant metastasis and death may occur. The management of these neoplasms is conservative surgery.