Scanning and Transmission Electron Microscopy of a Craniopharyngioma: X-ray Microanalytical Study of the Intratumoral Mineralized Deposits

This paper discusser the value of scanning electron microscopy (SEM) and x-ray microanalysis in the classification of craniopharyngiomas. This neoplasm shows epithelial nests, cords of cuboid cells, foci of squamous metaplasia, and microcystic degeneration. SEM reveals that the epithelial cysts are lined with elongated cells that possess numerous microvilli and blebs and that some cysts are lined with polyhedral cells. The microvilli are interpreted as characteristic of the fast growing craniopharyngiomas. A microanalytical study of the calcified areas reveals the presence of magnesium, phosphorus, and calcium.     

Mesothelial cyst of the adrenal gland

A case of mesothelium-lined cyst of the adrenal gland is reported. Although more than 300 adrenal cysts have been reported in the literature, epithelial cell-lined cysts are rare and comprise only 9% of the cases. An adrenal cyst was found, the lining cells of which had features consistent with mesothelial cells. The inner surtace of the cyst was lined by a single layer of cuboidal cells, which showed alcian blue positive cellular outline. Immunohistochemically, the lining cells were positively stained for keratin, epithelial membrane antigen and CA-125. Electron microscopic examination revealed many long complex microvilli and desmosomes in the lining cells. There was a basal lamina beneath the cell layer. These morphological and immunohistochemical findings indicated that the lining cell is derived from mesothelium.     

Ultramicroscopic Examination of the Ovine Tonsillar Epithelia

As solid morphological knowledge of ovine tonsillar epithelia might contribute to a better understanding of the pathogenesis of several diseases including prion diseases, the epithelia of all tonsils of 7 one‐year‐old Texel sheep were examined using scanning and transmission electron microscopy. Major parts of the pharyngeal and tubal tonsils were covered by pseudostratified columnar ciliated epithelia that were interrupted by patches of epithelium containing cells with densely packed microfolds or microvilli, and cells with both microvilli and cilia. Smaller parts were covered by either flattened polygonal cells with densely packed microvilli or microfolds, squamous epithelial cells, or patches of reticular epithelium. The palatine and paraepiglottic tonsils were mainly lined by squamous epithelial cells with apical microplicae or short knobs. Additionally, regions of reticular epithelium containing epithelial cells with apical microvilli were seen. The lingual tonsil was uniformly covered by a keratinized squamous epithelium and devoid of microvillous cells and patches of reticular epithelium. The rostral half of the tonsil of the soft palate was lined by a pseudostratified columnar ciliated epithelium with characteristics of the pharyngeal and tubal tonsils. The epithelium of the caudal part resembled the epithelia of the palatine and paraepiglottic tonsils. Putative M cells, mainly characterized by apical microvilli or microfolds and a close association with lymphoid cells, seem manifestly present on the nasopharyngeal tonsils. The reticular epithelium of the palatine and paraepiglottic tonsils also harbor cells with small apical microvilli. The exact nature of these presumptive M cells should, however, be elucidated in functional studies. Anat Rec, 2010. © 2010 Wiley‐Liss, Inc.     

Expression of leukemia inhibitory factor in craniopharyngioma

It has recently been reported that overexpression of leukemia inhibitory factor (LIF) in mice transgenic for LIF causes invagination of the anterior wall of Rathke’s pouch leading to the formation of cysts lined by LIF immunoreactive epithelial cells. Strong immunoreactivity was also found in human Rathke’s cleft cysts. Because such cysts and craniopharyngiomas share a common histogenesis, we raised the question of whether LIF is also expressed in craniopharyngioma. Fourteen histologically verified craniopharyngiomas of adamantinomatous type were examined for LIF immunoreactivity using the streptavidin-biotin-peroxidase complex method. Rabbit-anti-LIF antibody dilution 1:40) was applied to tissues having undergone antigen retrieval (microwaving in citrate buffer at pH 6). For positive control, nontumorous pituitary tissues were used. Primary antibody substituted with phosphate-buffered saline served as a negative control. By immunocytochemistry, the epithelial cells of all 14 craniopharyngiomas were LIF immunoreactive, showing varying degrees of staining intensity. In comparison, the connective tissue components of the tumors were immunonegative. Our study provides evidence that LIF is expressed in the epithelial cells of craniopharyngioma. Further investigation is required to elucidate the possible role of LIF in the development and progression of craniopharyngiomas.     

猫、兔、鼠侧脑室脉络丛的扫描电镜观察

本文报道用扫描电镜观察猫、兔和大白鼠侧脑室脉络丛的微细结构。3种动物侧脑室脉络丛表面均可见密集的微绒毛、散在的纤毛簇、单个的纤毛、球样突起和花样结构。在高倍镜下,微绒毛又可分为两型,即尖细的指样绒毛和末端膨大成泡样的微绒毛。并发现有呈花样密集排列的微绒毛簇。同时在3种动物的侧脑室脉络丛表面均可见kolmer细胞,根据突起的多少可将此类细胞分成为单极、双极,多极、无伪足样突起四型。猫的侧脑室脉络丛的球样突起和大白鼠的纤毛簇较多。     

Ultrastructural study of Helicobacter pylori-associated gastritis

Endoscopic biopsies of antral mucosa from 26 patients with Helicobacter pylori-associated gastritis were studied by electron microscopy (EM). Scanning electron microscopy (SEM) showed clustering of H. pylori in the intercellular areas, being entrapped by the microvilli which were decreased at the sites where the bacilli were seen. The observations of SEM were confirmed by transmission electron microscopy (TEM), which showed adherence of the bacilli to the cell surface, producing cup-shaped depressions in the epithelial cells, and occasionally intracellular infiltration by H. pylori. There were also depletion of mucus granules, degenerative changes, and disruption of intercellular junction complexes of the epithelial cells. Post-treatment biopsies showed complete disappearance of the bacilli, and ultrastructural changes associated with H. pylori infection were resolved.     

The amniotic, allantoic and yolk sac epithelia of the cat: SEM and TEM studies

Summary The epithelial layers of the feline allantoamnion and yolk sac between the 23rd day and full term were studied using SEM, TEM, and light microscopical histochemistry. Amniotic, allantoic and yolk sac fluid were analysed. The attenuated and relatively inert amniotic epithelium sloughs off completely around the 54th day, the amniotic cavity is then lined by fibrous connective tissue only. The exocoelomic epithelium is regarded as the source of the abundant macrophages, rich in lysosomal enzymes, that are seen in the allantoamniotic membrane after obliteration of the exocoelomic cleft. The allantoic epithelium has been mistaken for the amniotic one by many authors. Its cuboidal, glycogen-rich cells develop coral-like luminal outgrowths after the 45th day, which contain almost all kinds of organelles. The basal cell poles form large interdigitations, and the nuclei become heavily lobulated. The changes are accompanied by drastic alterations in the ionic composition of the allantoic fluid. The yolk sac endoderm differs greatly from the allantoic endoderm. It is the most active epithelium of the accessory fetal membranes. The yolk sac mesothelium retains many long microvilli over the whole gestational period. The nutritional value of the yolk sac fluid is only higher than that of the amniotic fluid in its glycerol and cholesterol values.     

Colloid Cyst of the Third Ventricle: A Comparative Ultrastructural Study of Neuraxis Cysts and Choroid Plexus Epithelium

Thirteen colloid cysts (CC), four Rathke cleft cysts (RCC), three follicular cysts of normal pituitary gland (FCP), four enterogenous cysts (EC), three normal choroid plexi (CP), three choroid plexus pa-pillomas (CPP), and several samples of normal bronchial mucosa and ependyma were studied by electron microscopy. The ultrastructure of most of the CC was indistinguishable from that of RCC, FCP, EC, and normal bronchial mucosa in demonstrating nonciliated and ciliated epithelial cells, goblet cells, basal cells, and intermediate forms, some showing evidence of early squamous differentiation. Two CC displayed mostly squamous differentiation, and one contained basally situated cells resembling myoepithelial cells. Although the RCC and FCP displayed features similar to those of CC, they also contained cells with electron-dense granules indicating pituitary hormone production and scattered cells showing oncocytic change. EC were lined by either squamous cells or mucin-producing columnar cells. Every CC, RCC, FCP, and EC contained cells covered by glycocalyx. In contrast to aforementioned lesions, ependymal lining, CP, and CPP were composed of a single cell type, one with numerous villi, few cilia, and no signs of keratiniza-tion, mucin production, or glycocalyx coating. It is concluded that the ultrastructural properties of CC are the same as those of cysts of endodermal or ectodermal origin and of respiratory mucosa. No ultrastructural similarities were observed between CC and normal or neoplastic neuroepitheiium. These ultrastructural findings support the concept of an enterogenous origin of colloid cysts and highlight their similarity to RCC.     

Colloid Cyst of the Third Ventricle: A Comparative Ultrastructural Study of Neuraxis Cysts and Choroid Plexus Epithelium

Thirteen colloid cysts (CC), four Rathke cleft cysts (RCC), three follicular cysts of normal pituitary gland (FCP), four enterogenous cysts (EC), three normal choroid plexi (CP), three choroid plexus pa-pillomas (CPP), and several samples of normal bronchial mucosa and ependyma were studied by electron microscopy. The ultrastructure of most of the CC was indistinguishable from that of RCC, FCP, EC, and normal bronchial mucosa in demonstrating nonciliated and ciliated epithelial cells, goblet cells, basal cells, and intermediate forms, some showing evidence of early squamous differentiation. Two CC displayed mostly squamous differentiation, and one contained basally situated cells resembling myoepithelial cells. Although the RCC and FCP displayed features similar to those of CC, they also contained cells with electron-dense granules indicating pituitary hormone production and scattered cells showing oncocytic change. EC were lined by either squamous cells or mucin-producing columnar cells. Every CC, RCC, FCP, and EC contained cells covered by glycocalyx. In contrast to aforementioned lesions, ependymal lining, CP, and CPP were composed of a single cell type, one with numerous villi, few cilia, and no signs of keratiniza-tion, mucin production, or glycocalyx coating. It is concluded that the ultrastructural properties of CC are the same as those of cysts of endodermal or ectodermal origin and of respiratory mucosa. No ultrastructural similarities were observed between CC and normal or neoplastic neuroepitheiium. These ultrastructural findings support the concept of an enterogenous origin of colloid cysts and highlight their similarity to RCC.     

Explant culture of human polycystic kidney

Autosomal dominant polycystic kidney disease is characterized by the formation of large fluid-filled epithelial cysts. To obtain renal cyst wall epithelium for in vitro study, we employed an explant culture technique using medium-hydrated collagen gel as the culture substrate. Pieces of excised cyst wall were submerged within collagen gel. Cells of the cyst lining migrated to form a polarized epithelium at the surface of the surrounding collagen gel. Regions of the outgrowth were isolated by microdissection and used as a source of cells for subculture. Cyst-derived epithelium retained the ultrastructural features of the renal cyst of origin. The cells were cuboidal and bore short apical microvilli. Cells often were joined by apical tight junctions. Intercellular channels were narrow and bordered by short microvillus projections at the basolateral membrane. Epithelial cells rested on a densely staining basal lamina. The explants commonly developed small solitary cysts within their wall that were filled with fluid. These mural cysts were lined by a simple epithelium morphologically similar to the cells that lined the explant. Explantation of human renal cyst wall to culture within collagen gel provides a reproducible method to isolate autosomal dominant polycystic kidney disease epithelium for subculture. This method offers an alternative to the use of proteolytic enzymes to establish morphologically stable cultures of cyst lining cells for use in experimental renal cystic disease.     

Chordoid Tumor: A Light, Electron Microscopic, and Immunohistochemical Study

Chordoid tumor-synonymous with chordoid sarcoma, parachordoma, and peripheral chordoma-is a very rare neoplasm with histologic similarity to chordoma that is found outside the axial skeleton. A soft tissue chordoid tumor in the gluteus maximus muscle of a 42-year-old man is presented. This tumor had morphologic features identical to a chordoma: nodular growth with vacuolated cytoplasm and myxomatous stroma by light microscopy, positive immunoreaction for cytokeratin and epithelial membrane antigen by immunohisto-chemistry, desmosomes, intercellular lumina lined with microvilli, and the presence of basal lamina material by electron microscopy. Two similar cases have been reported in the English literature.     

Development of the chick embryo endoderm studied by S.E.M

Summary The endoderm of a series of chick embryos from the unincubated egg to Hamburger and Hamilton stage 5 was examined by scanning electron microscopy (SEM). During this period the endoderm develops from a few scattered cells to a complete epithelial layer. Prior to the formation of the primitive streak endoderm cells can be observed delaminating from the ectoderm. These cells are round and have few processes except where they contact each other. At stage 2 cells appear in the endoderm over the primitive streak which have broad flat processes. This suggests that the cells originate directly from the streak. Away from the streak the endoderm cells are either smooth or have short microvilli. In later streak stages a mixture of smooth and some microvillous cells form a hexagonal pattern. This pattern is occasionally modified and holes are found in the endoderm with cell processes protruding from below the endoderm level. Sometimes whole cells, smaller and rounder than the majority of the endoderm cells are associated with this disturbance of the pattern. These cells are connected to the mesoderm by a long cytoplasmic process and it is suggested that they could be cells entering the endoderm from the middle layer, having accompanied the mesoderm cells through the primitive streak.     

The fine structure and histochemistry of human bile duct in obstruction and choledocholithiasis

Biopsies from the common bile ducts from seven patients undergoing surgery for biliary obstruction due to stones or malignancy were studied histochemically and electron microscopically. The surface of the bile duct is lined by a tall epithelium which extends into diverticula. Apically, they contain some neutral and sialated mucosubstances. Fucosyl residues were found in the Golgi apparatus and along the apical cell membrane. The latter is lined by microvilli. There was a well-developed rough endoplasmic reticulum and Golgi apparatus and a small number of apical secretory droplets. Large numbers of lipid droplets were present basally in some cells. Lipid-containing macrophages were also seen intra-epithelially and in the lamina propria. This suggests a possible pathway for lipid transport. The glands were lined by cuboidal cells, some containing much mucus--sulphated, sialated, and neutral with a basal nucleus. A well-developed endoplasmic reticulum and Golgi apparatus were found with abundant secretory droplets. The glandular epithelium contained lysozyme, alpha-1-antitrypsin, and alpha-1-antichymotrypsin. These may play a protective role. The lamina propria contained scattered smooth muscle cells amongst the fibroblasts and inflammatory cells.     

Scanning electron microscopy of normal, neoplastic and inflamed human bladder

Scanning electron microscopy (SEM) was used to compare the topographic fine structure of urothelium from normal, neoplastic and inflamed human bladders. The three groups of patients show different patterns. The normal bladder lining is characterized by regularly arranged large superficial cells with ridged surfaces. By contrast, the surface cells of a transitional cell carcinoma are rounded up and covered with microvilli. In some patients with cystitis or post inflammatory hyperplasia SEM appearances intermediate between normal and neoplastic patterns are encountered. However, except in extremely severe cystitis it is possible on SEM to differentiate between inflamed and neoplastic urothelium. Surface microvilli provide a useful malignant marker for transitional cell carcinoma. However, severe inflammation of the bladder, when diagnosed on cystoscopic examination, can and must be excluded by light microscopy before this marker is considered diagnostic for neoplasia.     

Fine structure of the alimentary canal of the larval blow fly <Emphasis Type="Italic">Chrysomya megacephala</Emphasis> (Diptera: Calliphoridae)

Morphology of the alimentary canal of the mature third instar larva of the blow fly, Chrysomya megacephala (F.), was examined using light, scanning, and transmission electron microscopy. Salivary structures consist of a single median deferent duct that bifurcates into efferent ducts connected to paired, tubular salivary glands comprised of closely packed conical-shaped epithelial cells with large nuclei. The crop occurs as a large, swollen diverticulum of the digestive tube and is lined internally with convoluted cuticle (epicuticle and endocuticle). The esophagus is a simple, straight tube internally lined with cuticle and externally encompassed by muscle fibers. The cardia is a bulb-like structure composed of anterior foregut tissue and posterior midgut tissue from which the peritrophic membrane (PM) is produced. The midgut begins within the cardia which is flanked posteriorly by four tubular gastric caeca that are lined internally with four to five layers of cuboidal epithelial cells bearing microvilli. Midgut tissue is lined with simple cuboidal epithelium whose cells are filled with numerous secretory granules and possessed long microvilli facing the lumen. A peritrophic membrane is contained within the midgut lumen. The larval hindgut consists of the pylorus, Malpighian tubules, ileum, colon, rectum, and anus, posteriorly. The pylorus is characterized by a single layer of epithelial cells encircled by a muscular layer and the presence of PM within the lumen. Malpighian tubules each diverge into two tubular structures totalling four long tubules of long chained cuboidal cells bearing microvilli internally. The wall of the ileum is comprised primarily of a monolayer of cuboidal epithelial cells with large oval nuclei and more intense muscular fibers surrounding the periphery. A cuticular layer surrounds the lumen containing the PM. This inner cuticle consists of a thin epicuticle that is electron-dense; whereas, the endocuticle is much thicker but less electron-dense. Myo-epithelial cells are dense in the anal region, where the PM persists.     

Thymic epithelial cysts in the pigeon.

Medullary epithelial cells forming cysts in the thymus of pigeon chicks were examined in order to clarify these morphological characteristics by immunohistochemical and electron microscopic techniques. Light microscopically, cysts were divided into intracellular and intercellular types. Intracellular cysts were positive for the periodic-acid Schiff reaction, while the intercellular type was not. With immunohistochemical staining for keratin, the edges of the intercellular cysts were moderately stained, whereas the cytoplasm of epithelial cells was weakly positive. Heterophils, eosinophils and lymphocytes were included in most of the intercellular cysts. Ultrastructurally, there were two types of epithelial cells which contained intracellular cysts densely packed with microvilli. They differed with regard to the shape of the rough endoplasmic reticulum and bundles of keratin filaments, and in the presence of large vacuoles. The walls of the intercellular cysts were composed of a single type of epithelial cell with a pale nucleus and bundles of keratin filaments. Small vesicles measuring 150 to 200 nm in diameter were numerous in the apical cytoplasm beneath the microvilli. In intercellular cysts, there were abundant heterophils, eosinophils, lymphocytes and macrophages which mostly appeared to be living cells. This evidence suggests that the intercellular cysts might provide a specific microenvironment for leukocytes in the pigeon thymus.     

Scanning electron microscopy of aortic medial changes in aortic ascending dilatation

The study of cystic cavities and collagen fibers fragmentation is useful to for a better knowledge of pathogenesis and surgical therapy of medial ascending aortic degeneration. Thus, the aim of this study was to describe by scanning electron microscopy the surfaces and shape of the cysts, measure their area, and identify microcystic spaces related to this degenerative disease. Scanning electron microscopy analysis was performed in 16 out of 36 patients who underwent surgery for ascending aorta dilatation with associated aortic valve disease. The aortic medial wall showed a cribrose appearance at low magnification (×50-100) and the intima was effuse. At high magnification (×500-2000), small cavities (clefts) lined by normal or fragmented elastic fibers and large cavities (pseudocystes) with anfractuous borders lined by fragmented elastic fibers and smooth muscle cells were observed. Furthermore, in the outer media wall microvessels lined by endothelium were also observed. These changes were lacking or less pronounced in normal aorta. SEM allows one to better identify the pathological cavities and to differentiate them from microvessels. These pathological cavities are more numerous and larger in the convexity than in the concavity of the aorta in according to our previous morphological and morphometric findings in asymmetrical aorta dilatation.     

Pancreatic neoplasms induced in Syrian golden hamsters. I. Scanning electron microscopic observations.

Pancreases from Syrian golden hamsters treated with N-nitrosobis(2-hydroxy-proply)amine for 10 to 25 weeks were examined under scanning electron microscopy (SEM). Findings indicate that the neoplasms originated from the ductal epithelium and developed progressively. Adenomas were lined by epithelium of differing cells types, ranging from a flat singly ciliated form to cuboidal-columnar types, or to mixed cell populations. The epithelial lining of the ductal carcinomas exhibited tubular and papillary cystic spaces, and cell surfaces were similar to the cuboidal and columnar epithelium of adenomas and of ductal epithelial hyperplasia. However, microvilli were dense and of varied lengths. The SEM observations correlated with patterns seen in routine histologic preparations.     

Apatite Determination and Distribution in an Early Stage of Gallbladder Calcification

This study is concerned with the nature and distribution of mineral in the gallbladder of a patient with chronic cholecystitis. Light and electron microscopic imaging revealed the mineral to be in the epithelial cells of the mucosa and fibroblasts of the submucosa. In the epithelial cells at the early stages of deposition, mineral was located in the nuclei and throughout the cytoplasm in association with interdigitating cell processes and apical microvilli but was absent in mitochondria. Elemental and electron diffraction analyses indicated the mineral inclusions to be apatite in nature.     

Glomerulocystic kidney disease in a Belgian Malinois dog: an ultrastructural, immunohistochemical, and lectin-binding study

Renal cysts in the cortex of a juvenile Belgian Malinois dog with acute renal failure were studied by means of light, scanning and transmission electron microscopy, immunohistochemistry for intermediate filaments, and binding for wheat germ agglutinin (WGA), peanut agglutinin (PNA), and Maclura pomifera agglutinin (MPA) lectins to determine the morphological and histochemical features of the epithelial cells of these cysts. The cysts were renal corpuscles with expanded urinary space. Glomerular tufts were small with poorly developed capillary loops and increased mesangial matrix. Continuity with the proximal tubule was evident in some cystic glomeruli. Two cell types lined Bowman's capsule. One was squamous with a central cilium and microvilli. The other had morphological and histochemical features of immature podocytes (parietal podocytes). These cells were round and protruded into the urinary space; they had thick cytoplasmic projections that resembled foot processes of podocytes, microvilli, and filtration slits. The parietal podocytes expressed vimentin and cytokeratins and had affinity for WGA as do normal immature podocytes. These features suggest that the parietal podocytes are derived by metaplasia of the parietal cells. The basement membrane of Bowman's capsule was irregularly thickened and showed multifocal glycosylation changes with lectin histochemistry (WGA, PNA, MPA) in areas adjacent to the parietal podocytes. Histologic and ultrastructural findings in this dog are consistent with glomerulocystic kidney disease. This is the second report of canine glomerulocystic kidney disease. Features are similar to those of the human counterpart, but it is unclear whether genetic defects cause the disease in the dog. The presence of parietal podocytes in all cysts suggests that abnormal differentiation may play an important role in the pathogenesis of this type of polycystic kidney disease.