Spindle cell carcinoma of the external auditory meatus with intracranial extension: histological, immunohistochemical and electron microscopic evaluation

We present a case of squamous spindle cell carcinoma of the external auditory meatus in a 38-year-old man. The tumour was extended to the inner ear, the temporal bone, the middle cranial fossa and the meningo-cerebral tissue. The surgical intervention of temporo-occipital craniotomy removed most of the neoplasia. At pathologic examination, the tumour showed an undifferentiated spindle cell pattern. Immunohistochemistry with a large antibody panel found a weak positivity only to EMA. The diagnosis was made when the electron microscopy showed rare junctional structures and tonofilaments.

Hints of a functional connection between the neuropeptidergic innervation of arteriovenous anastomoses and the appearance of epithelioid cells in the rabbit ear

Peripheral blood flow can be regulated by specialized vessel segments, the arteriovenous anastomoses. Their wall consists of a relatively thick layer of smooth muscle cells and so-called epithelioid cells. The epithelioid cell is a specialized myogenic cell phenotype expressing nitric oxide synthase. We studied the innervation of the different segments of arteriovenous anastomoses in the rabbit ear using antisera against neuropeptide Y, tyrosine hydroxylase, calcitonin gene-related peptide and substance P, as well as neuron-specific enolase, calbindin D and neurotubulin. The participation was especially examined of neuropeptidergic innervation and a possible morphological connection to the occurrence of epithelioid cells and a paracrine function. The NADPH diaphorase reaction and alpha-smooth muscle actin immunoelectron microscopy served to distinguish epithelioid cells from smooth muscle cells. Using conventional fluorescence microscopy and confocal laser scanning microscopy, we found the most dense innervation pattern of pan-neuronal markers (neurotubulin, neuron-specific enolase), tyrosine hydroxylase-immunoreactive nerve fibres and neuropeptidergic nerve fibres (neuropeptide Y, calcitonin gene-related peptide, substance P) around the intermediate segment in arteriovenous anastomoses, whereas the venous segment was barely marked. Single nerve fibres penetrated into the medial layer and reached the epithelioid cells. Using immunoelectron microscopy, we found intercellular contacts between epithelioid cells, but not the gap junction protein connexin 43. Here, we report for the first time a correlation of the innervation pattern with epithelioid cell type in arteriovenous anastomoses. Our findings suggest that epithelioid cells of the arteriovenous anastomoses are controlled by a dense network of neuropeptidergic nerve fibres in functional connection to their paracrine role as a nitric oxide producer.

Auditory epithelial migration. II: Morphological evidence for auditory epidermal cell migration in rat

Morphology of the tympanic membrane (TM) and external auditory canal (EAC) was studied in healthy, intact rat ears. TM-perforated ears (3 days after making the perforation) and TM-perforation-healed ears (14, 28 and 42 days after making the perforation). In intact ears, the epidermis in the annular region of the EAC displayed a characteristic appearance with cytoplasmic protrusions. We termed these protrusions as "finger-like projections". In contrast to the rat, the annular region of the EAC in the guinea-pig did not show "finger-like projections". Following a perforation in the centre of the anterior or the posterior quadrant of the pars tensa in rats the "finger-like projections" disappeared from the annular region on the perforated side of the EAC, while the projections remained on the malleus side of the perforation edge. In perforation-healed ears analysed 42 days after the perforation, the "finger-like projections" had recurred in the annular region on the perforated side of the EAC. The "finger-like projections" are likely to express maturation (keratinization) and desquamation of epidermal cells in the pars tensa and also could constitute morphological evidence of their migration on the TM.

A comparative study of perichondrial tissue in mammalian cartilages

The general organization, cellular and extracellular components, and structural variation of perichondrium have been studied in different mammalian cartilages by polarized light and transmission electron microscopy. The overall structure is that of a dense connective tissue composed of variable numbers of thin, stratified, closely-packed lamellae, themselves composed of closely-matted collagen fibres running in the plane of the cartilage surface, but oriented at various angles to each other. Variations mainly concern the arrangement of the fibre bundles in the transition zones between perichondrial and cartilage matrices, and between perichondrium and surrounding tissues. Perichondrial cells have the characteristics of fibrocytes. A cambial layer of undifferentiated stem cells was never observed. A layer of 'perichondrial lining cells' with distinctive ultrastructural characteristics was observed in some cartilage units, which separates the perichondrium from the surrounding loose connective tissue. The ultrastructural results demonstrate that the cartilage and perichondrial extracellular matrices are distinct, and what have been designated perichondrial 'transition' and 'proliferative' zones are in fact parts of the most superficial cartilage layer. Variations in perichondrial structure appear to correlate with diversity of cartilage function and we conclude that each cartilage unit plus perichondrium forms a tightly-integrated entity, best regarded as a unitary organ within the skeletal system.

External and middle ear pathology in TGF-alpha-deficient animals

Transforming growth factor-alpha (TGF-alpha) is a growth-regulatory peptide found in a wide range of embryonic and adult tissues. TGF-alpha is produced by keratinocytes and has been reported to be overexpressed in several epidermal diseases, including middle ear cholesteatoma. This report describes ear pathology in the waved-1 mutant mouse, which is severely deficient in TGF-alpha. Morphologic changes of the external and middle ear were studied histologically in waved-1 mutants 2 weeks to 6.5 months of age. Abnormalities found in the mutants included epidermal hyperplasia of the external ear canal (EAC) and tympanic membrane (TM) and enlargement of specialized sebaceous glands adjacent to the cartilaginous EAC. Sebum and desquamated keratin progressively accumulated within the EAC, displacing the TM into the middle ear. These changes appear similar to those occurring in Mongolian gerbils, which are known to develop cholesteatoma. The alterations found in waved-1 mutants are discussed in relation to the possible involvement of TGF-alpha in cholesteatoma pathogenesis.

Expression of neurotrophin receptor trkB in rat cochlear hair cells at time of rearrangement of innervation

The spatio-temporal distribution of the high-affinity neurotrophin receptor trkB was monitored during postnatal development of the rat cochlea. In addition to expression in presumptive afferent type I collaterals, afferent type II fibers, and efferent fibers, trkB immunoreactivity also transiently appeared in the sensory hair cells themselves, from postnatal days 5-9 in the basal turn, and from postnatal days 9-13 in the apical turn. A comparison of trkB with p75(NGFR), which is expressed in afferent and efferent fibers, and GAP-43 and synaptophysin, which are expressed in efferent fibers, revealed a time/space correlation of trkB receptor expression in hair cells with the rearrangement of their innervation. Co-expression of the neurotrophin receptor and its ligand has been proposed to be functionally involved in regulating the survival of neurons independent of target-derived neurotrophin factor. Thus, the presence of trkB in target hair cells, suggests that auto/paracrine mechanisms play a role during this critical period of rearrangement of neural connections.

Eosinophilic granuloma presenting as chronic otitis media: pitfalls in the diagnosis of aural polyps in children

The case of a 7-year-old boy with multifocal eosinophilic granuloma, initially presumed to be chronic otitis media, is presented. A review of other similar cases in the literature reveals that a delay in diagnosis is not uncommon, and a high index of suspicion is necessary to avoid an unfavourable outcome. Early in the evaluation of an aural polyp, sufficient biopsies should be performed and computerized tomography scanning should be considered.

[Electron microscopic observation of the denervated flap reinnervation after implantation of sensory nerve]

Flap reinnervation was studied by electron microscopy in the rabbit cervico-shoulder flap with great auricular nerve implanted. After transferring the flap to the dorsal defect of the rabbit's ear and division of its pedicle, the original nerve fibers of the flap underwent a degenerative process which would persist over 2 months. The great auricular nerve implanted into the flap regenerated axons by entering into old endoneurial rube of the flap and sprouting. The development process of the regenerating nerves showed that the unmyelinated fibers appeared first in the 2nd month, and the myelinated ones in the 4th month. The regenerating nerve fibers had often accompanied by blood vessels.

[The ultrastructural characteristics of the histopathological changes at the site of attachment to the host body of larvae of the ixodid tick Ixodes ricinus]

The attachment of ixodid tick Ixodes ricinus larvae to white mice and histopathology of host tissue in the attachment site were investigated by means of electronic microscopy. It was demonstrated the presence of cement substance around the mouthparts of tick during the first and the second days of feeding period and the absence of it at the last day of this period. The cement substance consists only of the cement cone (the external cement), situated on the surface of host epidermis. The tick mouthparts in the host dermis were surrounded by zone of modified collagene fibers. Examination of feeding site showed the intensive neutrophil migration and the formation of feeding cavity in 2 days after attachment of tick. At the same time the erythrocytes and active fibroblasts were found in the feeding cavity.

[Adenocarcinoma of the ceruminous glands: report of three cases]

We report three cases of ceruminoma seen in our department over a 1-year period and review the neoplasms of the ceruminous glands. According to the Welti classification, our three cases were ceruminous adenocarcinomas. Based on existing literature, ceruminous adenocarcinoma is the least frequent neoplasm of the ceruminous glands.

Tripartite differentiation (squamous, glandular, and melanocytic) of a primary cutaneous neuroendocrine carcinoma. An immunocytochemical and ultrastructural study

We report a case of primary cutaneous neuroendocrine carcinoma (PCNEC) with squamous, glandular, and melanocytic differentiation and associated Bowen disease. The paranuclear globular positivity of low-molecular-weight cytokeratins agrees with the ultrastructural observations of paranuclear fibrous bodies in the small neuroendocrine cells, while the diffuse cytoplasmic positivity corresponds to the sparse intermediate filaments in large cells with squamous differentiation. "Transitional forms" are characterized by both diffuse and globular cytoplasmic positivity for cytokeratins and by the ultrastructural evidence of neuroendocrine and squamous features. Therefore the ultrastructural demonstration of intracytoplasmic tonofibrils and tonofilaments, intercellular glandular lumina, lined by well-formed microvilli, and immature premelanosomes in the neurosecretory cells supports the proposed tripartite differentiation of neuroendocrine cells of this case of PCNEC.

Evaluation of commercially available antibodies to cytokeratin intermediate filaments and laminin in normal cat pinna

The pattern of distribution of cytokeratin (CK) intermediate filaments can be used to characterize subsets of epithelial tissues. The purpose of the study was to examine the CK expression of feline pinna skin. Six normal feline pinnae were routinely processed in formalin. An immunohistochemical method was used to stain the pinnae with 8 commercially available anti-human CK antibodies (Abs) (PKK1, CAM 5.2, UCD 10/11, 35BH11, 34BE12, AE1/AE3, MAK 6, A575) and an anti-human laminin Ab. All the CK Abs selectively localized to epithelium except 35BH11, which did not react with any part of the pinna. Some epithelial subsets were identified by their unique staining pattern with CK Abs. Basal cells but not suprabasal cells of the epidermis stained with PKK1; basal but not lumenal cells of apocrine glands stained with 34BE12. Apocrine glands stained with all CK Abs except 35BH11. All epithelial structures were stained with A575. Basal lamina of epithelial and mesenchymal tissues was clearly identified by the anti-laminin Ab. The results indicate that in cat pinna some commercially available anti-human CK Abs selectively stain subsets of epithelium and adnexa. PKK1, 34BE12, and A575 were the CK Abs with the most consistent staining patterns, the other Abs stained more variably from pinna to pinna. The pattern of epithelial and adnexal staining was similar but not identical to that reported for humans.

[Alkaptonuria-ochronosis]

The authors describe the case of a 40-year old female patient. Since her childhood she realised of her urine the black discoloration of the underwear. For about a year, without subjective complaints, blue-black color of the skin involved the axillae and pinnae. For a year appeared the increased pain of thoracal and lumbal spine column and the limitation of motion of these parts. The examination of urine, histological and electron microscopical findings, the X-ray photograph of the spinal column confirmed the diagnosis of alkaptonuria or rather congenital ochronosis.

Differentiation of the secondary elastic cartilage in the external ear of the rat

The cartilage in the external ear of the rat belongs to the group of secondary cartilages and it has a unique structural organization. The chondrocytes are transformed into typical adipose cells, the proteoglycan cartilage matrix is reduced to thin capsules around the cells and the rest of the extracellular matrix is occupied by a network of coarse elastic fibers. It appears late in development (16-day fetus) and needs more than one month for final development. The differentiation proceeds in several steps which partly overlap: the appearance of collagen fibrils, elastin fibers, the proteoglycan matrix, and the adipose transformation of chondrocytes. The phenotype of this cartilage and the course of its differentiation are very stable, even in very atypical experimental environmental conditions. The only exceptions are explants in organ culture in vitro and perichondrial regenerates. In these conditions the development of elastic fibers is slow and poor while the production of the proteoglycan matrix is abundant. The resulting cartilage then displays structural characteristics of hyaline cartilage rather than those of the initial elastic one.

Ultrastructural circadian variation of mast cells in the pinna of the mouse

It has been found previously under the light microscope that there was a circadian variation in mast cell number in the pinna of mice. The mast cell number was increased at 18.00 h and decreased at 06.00 h. In the current study, 5 mice of each group were synchronized for 4 weeks with a standard lighting regimen (light: 06.00-20.00 h; dark: 20.00-06.00 h). Both pinnas of every mouse of each group were removed at 06.00, 12.00, 18.00 and 24.00 h, respectively. Under the electron microscope, it was observed that more degranulated mast cells were found at 06.00 h and more intact mast cells were visible at 18.00 h. It appeared that the mast cell numbers, decreased and increased under the light microscope, were due to mast cell degradation and regranulation. This finding suggests that a functional circadian variation exists in the mast cell under physiological conditions.

[Ultrastructural characteristics of the histopathologic changes at the site of attachment to the host's body of larvae of the ixodid tick Hyalomma asiaticum]

Tissues of white mice in the place of the attachment of H. asiaticum larvae were examined by means of electron microscopy 2, 4, 24 and 72 hours after the attachment to the host. Fine structure of the cement sheath, peculiarities of its connection with host's tissues, fine structure of derm at different feeding stages of the tick are studied.

Differentiation of extracellular matrix in the cellular cartilage ("Zellknorpel") of the mouse pinna

Differentiation of cellular cartilage was studied in the mouse pinna with particular reference to matrix material. Fixation of glycosaminoglycans was performed by the use of acridine orange and elastin was identified by staining thin sections with tannic acid and uranyl acetate. Condensation of mesenchymal cells ("prechondroblasts") initiates the formation of a blastema of cartilaginous tissue at postnatal day 4. The synthesis of acidic glycosaminoglycans begins at postnatal day 8 when prechondroblasts transform to chondroblasts. Glycosaminoglycans can be detected within secretory vesicles of chondroblasts at postnatal day 8, in the extracellular space at postnatal day 13. Delicate collagen fibrils and elastic fiber microfibrils are seen between prechondroblasts and chondroblasts. Deposition of elastin begins at postnatal day 11. A network of elastic fibers and lamellae is formed, which replaces both collagen fibrils and elastic fiber microfibrils. In the interstice of mature cellular cartilage only elastin and proteoglycans are present (postnatal day 21). These findings indicate that cellular cartilage represents an independent kind of supporting tissue, which may serve as a progenitor of hyaline or elastic cartilage ("transitional cellular cartilage") but does not differentiate from hyalin cartilage.

Ultrastructural visualization of elastic fibres with a tannate--metal salt method

A modification of the tannic acid-metal salt method was applied as an ultrastructural stain for elastin. Thin sections of glutaraldehyde-fixed, embedded rat aorta and rabbit elastic cartilage, with and without osmication, were examined. Raising the pH of the tannic acid solution from 2.7 to 9.0 progressively increased the electron-density of elastic fibres and collagen fibrils in osmicated and unosmicated specimens. The maximum tannic acid staining of elastic fibres was observed in the pH range 7.0-9.0. Collagen staining, although less intense than that of elastic fibres, was also greatest in this pH range. Elastic fibres in osmicated specimens demonstrated the strongest tannic acid staining with a minimal increase in density of collagen and cell nuclei when compared to the unosmicated specimens. Sequential treatments of osmicated specimens with tannic acid pH 7.0-9.0, and uranyl acetate, pH 4.1, enhanced the density of the elastin intensely, increased collagen staining moderately, but hardly increased the density of nuclei and microfibrils. In elastase-digested osmicated specimens, all tannic acid (pH 7.0)-uranyl acetate-reactive elastin was selectively removed. These results demonstrate that all the neutral and alkaline tannic acid-uranyl acetate methods can be used as a postembedment stain for elastin specimens fixed in glutaraldehyde and osmium tetroxide.

[Structuro-functional organization of human elastic cartilage]

The light- and electron-microscopic investigation performed in order to study the elastic cartilage ultrastructure in the human concha auriculae has demonstrated that a peculiar feature of the later is abundance of elastic fibers both in its perichondrium and in the cartilagenous tissue. In the perichondrium the fibrillar elements (collagenous and elastic fibers) are oriented in parallel with the cartilagenous plate surface. There is not any definite regularity in the arrangement of the fibers of the cartilagenous tissue. As demonstrates the light microscopy, homogeneity of the ground substance is connected with a very compact arrangement of its fibrillar elements. Spaces between the fibers and fibrillae are filled with an amorphous ruthenium-positive substance of the proteoglycane nature.

X-ray microanalysis of cultured chondrocytes

Methodological aspects of X-ray microanalysis of cultured chondrocytes from rabbit auricular cartilage were investigated. The cells were grown on a Formvar-film covered carbon specimen holder with a hole, which allowed examination in STEM. Several different fluids for washing away the culture medium from the cells were used. The effect of these fluids on the elemental composition of the cells was studied. The composition of cultured chondrocytes was compared with that of auricular chondrocytes in situ. Washing with 0.3 M sucrose gave the most satisfactory results. Subsequently, the specimen holders could be frozen in liquid nitrogen and the cells freeze-dried. The effects of human growth hormone on rabbit chondrocytes were investigated by X-ray microanalysis and transmission electron microscopy. Although no ultrastructural effects of hormone treatment could be observed, marked changes in the elemental concentrations in nucleus and cytoplasm of the chondrocytes were detected.

Ultrastructure of elastic cartilage in the rat external ear

The structure of elastic cartilage in the external ear of the rat was investigated by transmission and scanning electron microscopy. The narrow subperichondrial, boundary zone contains predominantly ovoid cells rich in cell organelles: mitochondria, Golgi complex, granular endoplasmic reticulum and small (40--100 nm) vesicles. Scarce glycogen granules and bundles of 6--7 nm cytoplasmic filaments are also present. Deeper in the boundary zone, one or more cytoplasmic lipid droplets appear and cytofilaments become more abundant. Fully differentiated chondrocytes in the central zone of the cartilage plate resemble white adipose cells. They are globular and contain a single, large cytoplasmic lipid droplet. The cytoplasm is reduced to a thin peripheral rim; it contains a flattened nucleus, few cytoplasmic organelles and abundant, densely packed, cytoplasmic filaments. The intercellular matrix is very sparse. The pericellular ring consists of collagen fibrils about 20 nm in diameter and a proteoglycan cartilage matrix in the form of a "stellate reticulum". The complex of these two structures appears in the scanning electron micrographs as a a network of randomly oriented, ca 100 nm thick fibrils. Spaces between pericellular rings of matrix also contain thick elastic fibers or plates, apparently devoid of microfibrils. In scanning electron micrographs elastic fibers could be detected only in a few areas, in which they were not obscured by other constituents of the matrix. Immature forms of elastic fibers, oxytalan (pre-elastic) and elaunin fibers, were found in the perichondrial and boundary zones.

Light and electron microscopic study of ear cartilage in a case of relapsing polychondritis evolving under corticoid treatment

Light and electron microscope studies of the ear cartilage in a patient with relapsing polychondritis (RP) under corticoid treatment are reported. Unilateral auricular deformation evolved without inflammatory epidoses and the lesions consisted mainly of marginal erosions filled with fine collagen fibrils and containing degenerating perichondrial cells in their basal parts. Degenerative cells were scattered throughout the perichondrium, but cartilage erosions only occurred when numerous cells were affected in a same area. Cartilage outside the eroded zones did not seem to be modified. Cartilage lesions thus appear to be a result of a chondrocyte renewal defect leading to loss of proteoglycans and elastic fibers, with only collagen remaining. These data suggest that inflammation is probably not the initial pathogenic process responsible for cartilage injury in RP, but that a metabolic defect in perichondrial cells might be involved.

[Relapsing polychondritis. Histochemical, histoenzymological, immunofluorescent and ultrastructural studies of ear cartilage in three cases (author's transl)]

Ear cartilage has been studied by histochemistry, histoenzymology, immunofluorescence and electron microscopy in three cases of relapsing polychondritis. The most significant lesions have been observed at the cellular level, both by enzymology and electron microscopy: chondrocytes of peripheral zones seem to be first hypertrophic and then necrotic; at the opposite, their is no correlation between histochemical and electron microscopic studies about the chondroid intercellular substance whom lesions are probably secondary to the cellular ones. A few chondrocytes are positive with antiimmunoglobulins sera (IgM and IgA); this fact could be a proof of the dysimmune nature of this disease.

Electron microscope study of bone lesion in cholesteatoma otitis

Biopsy specimens were obtained at ear surgery of patients with cholesteatoma otitis and were studied by electron microscopy. The osseous tissue decalcified in EDTA demonstrated degradation of collagen matrix as well as extensive degeneration of bone cells. The surface of the eroded bone was found to be in direct contact with the subepithelial connective tissue or the granulation, but not with the keratinizing squamous epithelium of matrix. These results indicate that the bone destruction by cholesteatoma is of non-osteoclastic type and lend support to the view that the keratinizing squamous epithelium do not participate in bone destruction. One the ultrastructural basis, the inflammatory process in the soft tissue adjacent to bone and extensive degeneration of bone cells are considered as cardinal factors for bone destruction in this disease.

Hamster ear model for sebaceous glands

The ventral side of the earlobes of Syrian hamsters richly endowed with sebaceous glands. These glands are large and are similar to human sebaceous follicles since they have an infundibulum, a sebaceous duct, multiple lobules, and a pilary unit which enters from below into the gland. In this study we have measured gland size by planimetry,and cellular activity by autoradiography using tritiated thymidine and tritated histidine. Males have much larger glands in sagittal sections than do females(0.1750 mm2 vs 0.0727 mm2, p less than 0.001) and a higher labeling index (19.85% vs 14.3%, p less than 0.01). Injection of testosterone propionate increases the gland size in female hamsters to 0.2362 mm2 (p less than 0.001). The labeling index also increases. The turnover of the total gland population is 12 to 14 days. Androgen sensitivity, gland size, and turnover time make the sebaceous glands on the ventral surface of the hamster earlobe a suitable model for study.

Relapsing polychondritis: an ultrastructural study

Ear cartilage from a typical case of relapsing polychondritis was examined with the electron microscope. A large number of dense granules and vesicles, which were compatible with matrix vesicles or lysosomes, surrounded the affected chondrocytes. In less severely damaged chondrocytes, these granules and vesicles appeared to be formed by pinching off of the cytoplasmic processes or by budding from the processes. Calcification of the granules was minimal. In severely damaged chondrocytes, an admixture of these granules and cytoplasmic organelles occurred. It is speculated that many of these dense granules are lysosomal in nature and that they may produce inflammation and reduce the proteoglycan content of cartilage.

Pathogenesis of gangrene following intra-arterial injection of drugs: a new hypothesis

We have demonstrated the toxicity of diazepam and the safety of ketamine hydrochloride following intra-arterial injection in an anaesthetized animal model. The pathogenesis of gangrene following intra-arterial injection of drugs is unclear. Clinical reports and this experiment suggest that it only follows injection of highly membrane-soluble drugs. Early swelling and disruption of capillary endothelial cells were demonstrated after intra-arterial injection of diazepam and thiopentone. We believe that a theory of pathogenesis based on this finding is consistent not only with our experimental findings, but with known in vitro effects of membrane soluble drugs on cell membranes and the clinical features following intra-arterial injections in both human subjects and in animals.

Electron microscopic observations on the repair of perforated tympanic membranes in the guinea-pig

Experimental perforations of the tympanic membrane in the guinea-pig have been examined electron microscopically. The perforation site became filled with maturing granulation tissue, covered on its external (meatal) and internal (middle ear) surfaces by cells derived from the epithelia of the respective surfaces of the normal membrane. The fibrils and interfibrillar matrix of the normal tympanic membrane in this species have a unique ultrastructure. The fibrils are quadrangular, apparently composed of four subunits, and the surrounding matrix is more electron-dense than in most connective tissues. During repair this type of fibril and matrix was not reconstituted within the 6 month period examined. In its place were formed fibrils of varying diameter, probably collagenous, and differing from those of normal membrane both in size and in the lack of characteristic interfibrillar matrix. The fibroblasts of the wound site, even if of local origin, thus do not appear to be capable of synthesizing the local type of connective tissue.