A Method to Administer Agents to the Larynx in an Awake Large Animal

PURPOSE

This research note describes an adapted experimental methodology to administer an exogenous agent to the larynx and upper airway of awake animals. The exogenous agent could be a perturbation. In the current study, the agent was isotonic saline. Isotonic saline was selected because it is safe, of similar composition to extracellular fluid, and used in voice studies. The described approach allowed large animals such as pigs to be comfortably restrained without chemical sedation or anesthesia for extended periods while receiving the agent.

METHOD

Six Sinclair pigs were successfully trained with positive reinforcement to voluntarily enter and then be restrained in a Panepinto Sling. Once restrained, the pigs accepted a nose cone that delivered nebulized isotonic saline. This procedure was repeated 3 times per day for 20 days. At the end of the study, the larynx and airway tissues were excised and examined using histology and transmission electron microscopy.

RESULTS

Pathology related to the procedure (i.e., nebulized inhaled isotonic saline or stress) was not identified in any examined tissues.

CONCLUSIONS

This methodology allowed for repeated application of exogenous agents to awake, unstressed animals. This method can be used repeatedly in the laboratory to test various therapeutics for safety, toxicity, and dosage. Future studies will specifically manipulate the type of agent to further our understanding of laryngeal pathobiology.

The influence of low-dose cadmium on the laryngeal microstructure and ultrastructure of Pelophylax nigromaculata

Cadmium (Cd) is one of the common heavy metals dispersed throughout the modern environment that disrupts the development of aquatic organisms. Amphibians appear to be particularly vulnerable to this heavy metal contaminant since their eggs and aquatic larvae live in aquatic habitats and have permeable skin. During this critical sensitive period, amphibians live primarily in the water and are thus susceptible to the effects of environmental pollutants in water. Pelophylax nigromaculata completes their laryngeal development from Gosner stage 19 (GS 19, embryonic stage) to GS 46 (metamorphosis stage). To study whether long-term (from GS 19 to GS 46) exposure to low Cd concentrations (0, 4, 8, 16, 32, 64, and 128 μg/L) affects the development of the larynx in P. nigromaculata, a comparative study of microstructures and ultrastructures of female and male P. nigromaculata larynges was carried out. In histological structure, the larynx was composed of epithelial tissue, skeletal muscle, and hyaline cartilage, and there were no differences between male and female frogs except that males had a larger cross-section area than females. In contrast to controls, 64 and 128 μg/L Cd treatments caused a significant decrease in cross-sectional area, while other treatments showed no significant differences. Under the scanning electron microscope, the surface of the larynx could be seen to be attached to developed and evenly distributed cilia, with no significant differences between young male and female frogs, even among the Cd treatments. Under transmission electron microscopy, developed laryngeal epithelial cells could be observed, with obvious cross striations of skeletal muscle cells and mitochondria distributed around the muscle and skeletal muscle satellite cells. Compared with the control group, mitochondria around the skeletal muscle grew in size and decreased in number in the high-concentration treatment.

Sperm Protein 17 Is Expressed in Human Somatic Ciliated Epithelia

It was once believed that sperm protein 17 (Sp17) was expressed exclusively in the testis and that its sole function was to bind to the oocyte during fertilization. However, immunohistochemistry of the human respiratory airways and reproductive systems show that it is abundant in ciliated cells but not in human cells with stereocilia and microvilli. The high degree of sequence conservation throughout its N-terminal half, and the presence of an A-kinase anchoring protein (AKAP)-binding motif within this region, suggest that Sp17 plays a regulatory role in a PKA-independent AKAP complex in both male germinal and ciliated somatic cells.

Antigen challenge induces a supraglottic but not a subglottic edema in the rat larynx

OBJECTIVE: To examine the reaction of mast cells in the larynx of sensitized rats after allergen challenge and determine whether a type I hypersensitivity reaction can elicit a supraglottic and subglottic edema.

STUDY DESIGN: Rats were sensitized with ovalbumin (OA) and challenged 3 weeks later by intravenous injection of either OA or NaCl and perfused with glutaraldehyde. The larynges were removed and processed for light and electron microscopy. Sections from the epiglottis and subglottic region were examined.

RESULTS: In challenged animals, the connective tissue mast cells (CTMC) in the epiglottic submucosa, but not the mucosal mast cells (MMC) in epithelium, were significantly reduced compared with the case of controls, and the connective tissue was edematous. In the subglottic region, the number of both MMC and CTMC was reduced (albeit not significantly), and there was no edema in the lamina propria.

CONCLUSIONS: Allergen challenge induces a marked edema in the epiglottis but not in the subglottic area.

SIGNIFICANCE: The results indicate that the supraglottic and subglottic regions react differently to allergen challenge. (Otolaryngol Head Neck Surg 2005;132:694-700.)

Mutational falsetto: intervention outcomes in 45 patients

Objective:

The aim of this study was to evaluate the outcomes of therapeutic intervention in patients with mutational falsetto, by applying perceptual and acoustic analysis before and after voice therapy.

Materials and methods:

Forty-five consecutive patients with mutational falsetto were studied retrospectively. Acoustic analysis (i.e. fundamental frequency, jitter, shimmer, and formants one, two and three) was performed using the Multi-Dimensional Voice Program. Perceptual voice analyses were performed, including graded severity–roughness–breathiness–aesthenicity–strain assessment.

Results:

Subjects' fundamental frequency, voice formants one, two and three, jitter, and shimmer were greater before than after treatment. There were statistically significant differences between pre- and post-treatment average values for fundamental frequency, jitter and shimmer. There were also statistically significant differences between pre- and post-treatment average values for formants one and two. These results were maintained after six months of follow up, and there was no significant difference between results at three- and six-month follow up. According to perceptual evaluation, each subject's voice had altered from mutational falsetto to chest voice by completion of the intervention. Thus, all of the patients successfully lowered their modal speaking voice to an appropriate level.

Conclusion:

In the light of objective evaluations, and by applying the study treatment protocol, these results suggest that normal voice can be maintained after intervention, at six months' follow up.

Laryngektomia jako postępowanie ratujące u chorych z nasilonym odczynem popromiennym po radioterapii raka krtani

INTRODUCTION

Author discusses problems and treatment principles of patients with massive postradiation injury, who had laryngectomy procedure as a result of insufficience of the farmacological treatment.

MATERIAL AND METHODS

There were 12 patients who were performed laryngectomy as a treatment of massive postradiation injury of the larynx in the period 1975-2005. We suspected presence of persistent neoplasm with postradiation changes. Seven laryngectomies were performed after confirmation of the neoplasm in 1-3 biopsies. Three patients were treated operatively without this confirmation in spite of two biopsies which were negatively, and two patients were treated in this way without biopsies.

RESULTS

Two patients had tomour free postlaryngectomy specimens in the histopathological examinations, and among 10 others the reccurence of the tumour after radiotherapy was present during the post-laryngectomy histopathological examinations. In 7 cases this reccurence was proved with massive postradiation injury in endoscopic biopsies before laryngectomy.

DISCUSSION

Author presents his own problems and presents methods of treatment of the patients with massive postradiation injury of the larynx described in literature.

Annexin 1: Differential expression in tumor and mast cells in human larynx cancer

Annexin 1 protein (ANXA1) expression was evaluated in tumor and mast cells in human larynx cancer and control epithelium. The effect of the exogenous ANXA1 (peptide Ac 2-26) was also examined during the cellular growth of the Hep-2 human larynx epidermoid carcinoma cell line. This peptide inhibited the proliferation of the Hep-2 cells within 144 hr. In surgical tissue specimens from 20 patients with larynx cancer, ultrastructural immunocytochemistry analysis showed in vivo down-regulation of ANXA1 expression in the tumor and increased in mast cells and Hep-2 cells treated with peptide Ac2-26. Combined in vivo and in vitro analysis demonstrated that ANXA1 plays a regulatory role in laryngeal cancer cell growth. We believe that a better understanding of the regulatory mechanisms of ANXA1 in tumor and mast cells may lead to future biological targets for the therapeutic intervention of human larynx cancer.

In vivo optical coherence tomography of the human larynx: normative and benign pathology in 82 patients

OBJECTIVES

Optical coherence tomography (OCT) is an emerging imaging modality that combines low-coherence light with interferometry to produce cross-sectional images of tissue with resolution about 10 mum. Patients undergoing surgical head and neck endoscopy were examined using a fiberoptic OCT imaging probe to study and characterize microstructural anatomy and features of the larynx and benign laryngeal pathology in vivo.

STUDY DESIGN

Prospective clinical trial.

MATERIALS AND METHODS

OCT imaging of the larynx was performed in 82 of 115 patients who underwent surgical endoscopy for various head and neck pathologies. The OCT device employs a 1.3 microm broadband light source (FWHM, 80 nm). The frame rate is 1 Hz. Imaging was performed using a handheld probe placed in near contact with the target site. The maximum axial and lateral dimensions for the region of interest imaged were 2.5 mm x 6 mm, with resolutions of 10 microm. Simultaneously, conventional endoscopic images were obtained to provide anatomic correlation with OCT images and histology. Optical micrometry was performed to measure the epithelium thickness.

RESULTS

Systematic OCT imaging of laryngeal structures and subsites provided information on the thickness of the epithelium, integrity of the basement membrane, and structure of the lamina propria. Microstructural features identified included glands, ducts, blood vessels, fluid collection/edema, and the transitions between pseudostratified columnar and stratified squamous epithelium. The mean epithelial thickness of laryngeal subsites was calculated: true vocal cord (129 microm), false vocal cords (124 microm), aryepiglottic fold (177 microm), subglottis (98 microm), and epiglottis (185 microm). True vocal cord pathology imaged included Reinke's edema, papillomatosis, polyps, mucous cysts, and granulation tissue. Subglottic imaging identified boundaries between epithelium, lamina propria, and cartilage. The OCT images compared favorably with conventional histopathology.

CONCLUSION

OCT has the unique ability to image laryngeal tissue microstructure and can detail microanatomic changes in benign, premalignant, and malignant laryngeal pathologies. OCT holds the potential to guide surgical biopsies, direct therapy, and monitor disease, particularly when office-based systems are developed. This is a promising imaging modality to study the larynx.

Characterisation of adherens and tight junctional molecules in normal animal larynx; determining a suitable model for studying molecular abnormalities in human laryngopharyngeal reflux

BACKGROUND

The disruption of intercellular junctions in the larynx is a pathological feature of laryngopharyngeal reflux (LPR). Good experimental models are necessary to gain greater insight into the molecular mechanisms and alterations that result from abnormal exposure of the laryngeal epithelium to acid refluxate.

AIMS

To characterise laryngeal tissues from different species to determine the most suitable for use in experimental studies of LPR.

METHODS

Human and non-human laryngeal tissues (mouse, rat, guinea pig, porcine, and rabbit) were studied. Histological characterisation was performed by light microscopy. The expression and subcellular localisation of adherens junctional molecules (E-cadherin and beta catenin) was evaluated by immunohistochemistry, and tight junction molecules (occludin and zonula occludens 1 (ZO-1)) by western blotting. The ultrastructural features of porcine and human tissue were assessed by electron microscopy.

RESULTS

Porcine tissue revealed both respiratory-type and stratified squamous epithelium, as seen in the human larynx. The expression and subcellular localisation of the E-cadherin-catenin complex was detected in all species except mouse and rat. The pattern of ZO-1 and occludin expression was preserved in all species.

CONCLUSION

The expression of intercellular junctional complexes in porcine epithelium is similar to that seen in humans. These results confirm the suitability of these species to study molecular mechanisms of LPR in an experimental system.

?-Gustducin immunoreactivity in the airways

The G-protein subunit alpha-gustducin is a marker of chemoreceptive cells. In the present study, we examined the immunohistochemical localization of alpha-gustducin in rat airway epithelium both by light and electron microscopy. alpha-Gustducin immunoreactivity was found in solitary cells that presented ultrastructural features of chemoreceptor cells, i.e. flask-shaped or pear-shaped, with an apical process with thin microvilli protruding into the lumen. The immunostaining was mainly concentrated in the apical process and along the basolateral cell surface. To investigate whether alpha-gustducin-immunoreactive cells represented a distinct cell subset in rat airways, we performed double-label immunocytochemistry with antibodies to protein gene groduct (PGP) 9.5, a marker of neuroendocrine cells, and to phospholipase C beta2 (PLCbeta2), a component of the bitter signalling pathway. alpha-Gustducin-immunoreactive cells were present in a subset of PGP-9.5-immunoreactive elements, although not all alpha-gustducin-positive cells expressed PGP 9.5 labelling. In addition, a subset of alpha-gustducin-expressing cells colocalized PLCbeta2. This work thus demonstrates that solitary alpha-gustducin-immunoreactive cells exist throughout the airways and represent a specialized cell type with morphological and immunohistochemical characteristics of chemoreceptor cells.

Identification and characterization of a specific sensory epithelium in the rat larynx

A specific laryngeal sensory epithelium (SLSE), which includes arrays of solitary chemoreceptor cells, is described in the supraglottic region of the rat. Two plates of SLSE were found, one on each side of the larynx. The first plate was located in the ventrolateral wall of the larynx, and the second was located in the interarytenoidal region. In SLSE, immunoblotting showed the presence of alpha-gustducin and phospholipase C beta2 (PLCbeta2), which are two markers of chemoreceptor cells. At immunocytochemistry, laryngeal immunoreactivity for alpha-gustducin was localized mainly in solitary chemosensory cells. Double-label immunocytochemistry using confocal microscopy demonstrated that alpha-gustducin-expressing cells in large part colocalize type III IP3 receptor (IP3R3), another key molecule in bitter taste perception. However, some IP3R3-expressing cells do not colocalize alpha-gustducin. At ultrastructural immunocytochemistry, these cells showed packed apical microvilli, clear cytoplasmic vesicles, and cytoneural junctions. SLSE was characterized by high permeability to a tracer due to poorly developed junctional contacts between superficial cells. Junctions were short in length and showed little contact with the terminal web. Ultrastructural analysis showed deep pits among the superficial cells. In SLSE, high density of intraepithelial nerve fibers was found. The lamina propria of the SLSE appeared thicker than that in other supraglottic regions. It was characterized by the presence of a well-developed subepithelial nerve plexus. The immunocytochemical and ultrastructural data suggested that SLSE is a chemoreceptor located in an optimal position for detecting substances entering the larynx from the pharynx or the trachea.

Taste buds and nerve fibers in the rat larynx: an ultrastructural and immunohistochemical study

We investigated the rat laryngeal taste buds and their innervation by electron microscopy and immunohistochemical methods. Taste buds were densely arranged in the surface facing the laryngeal cavity of the epiglottis, the aryepiglottic fold, and the cuneiform process of the arytenoid cartilages. The cells of the buds were classified into types I, II, III, and basal cells, the ultrastucture of which was almost the same as that previously reported in lingual taste buds. The type III cells that had synaptic contacts with nerve fibers were considered to be sensory cells. Immunohistochemical analysis revealed thick calbindin D28k-immunoreactive fibers and thin varicose fibers immunoreactive for calcitonin gene-related peptide or substance P in and around the taste bud. Serotonin-immunoreactive cells were also observed here. The results revealed the innervation pattern of laryngeal taste buds to be the same as that in lingual taste buds. Carbonic anhydrase (CA) is known to catalyze the hydration of CO2 and dehydration of H2CO3, and seems to be essential in CO2 reception. Immunoreactivity for CAI was detected in slender cells and that for CAIII was observed in barrel-like cells in the laryngeal taste buds. The pH-sensitive inward rectifier K+ (Kir) channel in the cell membrane may be involved in CO2 reception as well. CAII-reactive cells were also reactive to Kir4.1, PGP 9.5 and serotonin. Our results indicated that CAII and Kir4.1 are located in type III cells of the laryngeal taste buds, and supported the idea that the buds may be involved in the recognition of CO2.

Toluene diisocyanate exposure induces laryngo-tracheal eosinophilia, which can be ameliorated by supplementation with antioxidant vitamins in guinea pigs

OBJECTIVE

Toluene diisocyanate (TDI)-induced asthma is a common cause of occupational lung disease. In addition, a sore throat is one of the complaints of TDI-exposed workers. The aim of the present study was to determine whether TDI exposure induces laryngeal and/or tracheal lesions in experimental animals.

MATERIAL AND METHODS

Guinea pigs underwent naris application of TDI three times, and their respiratory tracts were then examined using light and electron microscopy. Some animals simultaneously received vitamins C and E. which function as antioxidant agents.

RESULTS

When TDI-treated animals showed the clinical sign of labored breathing, many eosinophils had appeared in the lamina propria and mucosa of both the larynx and trachea, which finally infiltrated the tract lumen through the ruptured epithelium. Laryngo-tracheal inflammation was more severe than that observed in the lungs. However, supplementation with antioxidant vitamins in TDI-treated animals ameliorated the respiratory eosinophilia.

CONCLUSION

Naris application of TDI induced laryngotracheitis. which was significantly suppressed by the antioxidant vitamins, This implies a preventive effect of the vitamins on this occupational disease.

3D structure of the macula flava in the human vocal fold

OBJECTIVE

To investigate the 3D structure of the macula flava in the human vocal fold.

MATERIAL AND METHODS

The 3D structure of the macula flava in the human vocal fold was investigated by means of scanning electron microscopy using a chemical digestion method (modified sodium hydroxide maceration method) and the results compared with those obtained using light microscopy.

RESULTS

The macula flava of the human vocal fold comprised a dense mass of cells and extracellular matrices. Many cells were stellate in shape and possessed cytoplasmic processes. Extracellular matrices were composed of collagenous, reticular and elastic fibers, and ground substances (hyaluronic acid). Many fibers ran in various directions. The stellate cells were surrounded by these extracellular matrices. Amorphous materials were attached to the surface of the stellate cells. Extracellular matrices in the macula flava extended to those in the lamina propria of the vocal fold mucosa.

CONCLUSION

Anterior and posterior maculae flavae in the human vocal fold mucosa are postulated to be involved in the metabolism of extracellular matrices, which are essential to the viscoelasticity of the lamina propria (the vibrating tissue) of the human adult vocal fold mucosa.

Morphology of the nerve endings in laryngeal mucosa of the horse

To discuss the significance of laryngeal sensation on various disorders of the horse, we studied the morphological and topographical characteristics of sensory structures in the laryngeal mucosa using immunohistochemistry and immunoelectron microscopy. Various sensory structures, i.e. glomerular endings, taste buds and intraepithelial free nerve endings, were found in the laryngeal mucosa by immunohistochemistry for protein gene product 9.5 (PGP 9.5) and neurofilament 200kD (NF200). Glomerular nerve endings were distributed mainly in the epiglottic mucosa; some endings were also found in the arytenoid region arising from thick nerve fibres running through the subepithelial connective tissue. Some terminals directly contacted the epithelial cells. Taste buds were distributed in the epithelium of the epiglottis and aryepiglottic fold. In the whole mount preparation, the taste buds were supplied by the terminal branching of the thick nerve fibres. In some cases, the taste buds were arranged around the opening of the duct of the epiglottic glands. The intraepithelial free nerve endings were found to be immunoreactive for substance P (SP) and calcitonin gene-related peptide (CGRP). These nerve endings were surrounded by the polygonal stratified epithelial cells in the supraglottic region, and by the ciliated cells in the subglottic region. The density of the intraepithelial free nerve endings was highest in the corniculate process of the arytenoid region and lowest in the vocal cord mucosa. The densities of CGRP- and SP-immunoreactive nerve endings in the arytenoid region were (mean +/- s.d.) 30.6+/-12.0 and 10.0+/-4.9 per unit epithelial length (1 mm), respectively and in the vocal fold mucosa, 1.1+/-0.9 and 0.8+/-0.7, respectively. Approximately one half of the CGRP immunoreactive nerve endings were immunoreactive for SP, and most SP-immunoreactive nerve endings were also immunoreactive for CGRP. Well-developed subepithelial plexus with numerous intraepithelial fibres were observed in flat or round mucosal projections that existed on the corniculate process of the arytenoid region. In conclusion, the laryngeal mucosa of the horse seems to have morphology- and/or location-dependent sensory mechanisms against various endo-and exogenious stimuli.

Distribution of tracheal and laryngeal mucous glands in some rodents and the rabbit

We used scanning electron microscopy to count the number of mucous gland openings in the tracheae and lower portion of the larynges of the rat, guinea pig, hamster, mouse and rabbit. Cells of the airway surface epithelium were removed by protease digestion better to visualise the gland openings. The distribution of glands was further studied by conventional histology and by PAS/Alcian blue staining of whole mounts. In all rodent species, gland openings in the larynx occurred with a frequency of 1-2 per mm2. Mice had no gland openings in their tracheae, and hamsters, only a handful. Rat tracheae contained 126+/-42 gland openings (+/-S.D.; n = 6) at a frequency of approximately 0.6 per mm2 at the top of the trachea and approximately 0.15 per mm2 at the bottom. Guinea pig tracheae contained 153+/-90 gland openings (+/-S.D.; n = 5), with 54% being in the top 40% of the trachea. In both rat and guinea pig, tracheal glands were found in the ventral aspect between the cartilaginous rings, and were absent from the dorsal membranous portion. Gland openings in most species were simple circles of approximately 50 microm diameter. However, glands in the rat trachea generally opened obliquely into shallow (approximately 20 microm deep) oval troughs (approximately 150 x 75 microm), which had their long axes oriented from head to tail. In the rabbit, there was no evidence of tracheal or laryngeal glands histologically. However, the tracheal and laryngeal surfaces contained numerous pits (approximately 30 microm diameter) distributed evenly over and between cartilages at a frequency of approximately 4 per mm2. These may correspond to the 'nests' of goblet cells described by others.

Influence of phonation on basement membrane zone recovery after phonomicrosurgery: a canine model

The process of wound healing at the basement membrane zone of the vocal folds after phonomicrosurgery was investigated. The influence of phonation and the implied optimal period of voice rest were considered. Phonomicrosurgery was performed on both vocal folds of 20 adult dogs. In 10 dogs, the left recurrent laryngeal nerve was simultaneously resected to simulate iatrogenic voice rest; the remaining 10 dogs were allowed to phonate normally. The healing process of the vocal folds of each group was observed at 1, 2, 4, 8, and 12 weeks after surgery with immunohistochemical staining and transmission electron microscopy. In the voice rest group, the basement membrane was completely re-formed in 2 weeks, and the "cover" appeared completely rearranged by 8 weeks. The results of the phonation group were characterized by a delayed healing process and basement membrane changes. These results suggest that voice rest of at least 2 weeks after surgery may be beneficial and that vocal hygiene should be maintained for as long as 8 weeks.

Androgen receptors and sexual dimorphisms in the larynx of the bullfrog

As in most anuran amphibians, both male and female bullfrogs (Rana catesbeiana) vocalize. Sex differences in vocalizations in the bullfrog may be due to sex differences in the larynx. We examined the laryngeal muscle to determine whether it possessed androgen receptors and whether there were morphological sexual dimorphisms in the larynx. Using a polyclonal antibody and immunocytochemistry, we found androgen receptors in the laryngeal dilator muscle of both sexes. Males possessed approximately 13% more receptor-positive muscle nuclei than females. We also stained the dilator muscle for the presence of succinate dehydrogenase. Density of staining for the enzyme was significantly greater in male muscle than in female muscle, indicating greater oxidative capacity of muscle in males. This procedure also showed both a significantly greater cross-sectional area for the dilator muscle in males and a greater area for individual fibers. Male muscle consisted almost entirely of fast-twitch oxidative/glycolytic fibers. Female muscle contained a mixture of fast-twitch glycolytic fibers and two subclasses of fast-twitch oxidative/glycolytic fibers. Finally, both the length and width of the entire laryngeal complex and the length and width of the dilator were significantly greater in males than in females. In summary, laryngeal muscle of bullfrogs possessed androgen receptors and is thus likely to be androgen sensitive. Androgens, during development or at adulthood, may be responsible for the anatomic and enzymatic sexual dimorphisms in the larynx.

Age-related changes in the human laryngeal glands

The present study was conducted to determine age-related changes in the human laryngeal glands by means of excised human adult larynges. Scanning and transmission electron microscopic observations were made. The results obtained are summarized as follows. 1) Granular endoplasmic reticulum and Golgi apparatus were sparse in the cytoplasm of serous and mucous cells. 2) Secretory granules in serous cells had decreased in number. 3) Secretory granules were less electron-dense compared to those in younger adult specimens, but were electron-lucent. 4) Mucigen droplets in mucous cells were not as numerous as those in younger adults. 5) Discharge of secretory granules and mucigen droplets had decreased. 6) Age-related morphologic changes in the laryngeal glands influenced not only the amount but also the quality of secretions. 7) The above changes lessened lubrication of the vocal folds, thus causing aging of the voice to some extent. 8) Local immunity and mucociliary transport were also affected. 9) Age-related changes in the laryngeal glands partially altered laryngeal function.

Edema formation in the rat larynx

In the rat larynx, plasma exudation and edema formation were studied by light and electron microscopy after i.v. injections of the mast cell activator compound 48/80, substance P, and capsaicin. The morphological effects of substance P and capsaicin on connective tissue mast cells in vivo were also examined. Of the drugs tested, only compound 48/80 degranulated the connective tissue mast cells. All drugs induced a subepithelial plasma exudation in the subglottic region, with edema in the lamina propria and widened intraepithelial intercellular spaces, though the tight junction regions seemed intact. In the epiglottis, 10 min after compound 48/80 injection, there was edema in the lamina propria on the lingual side, with an intact and tight epithelial lining. No morphological sign of edema was found in the epiglottis after injection of substance P or capsaicin. The pronounced effect found in the epiglottic region after compound 48/80 injection was due to the release of mediators such as histamine and 5-hydroxytryptamine from the connective tissue mast cells. This study supports the belief that substance P in vivo mediates an increased vascular permeability by a direct effect on the blood vessels - a mechanism distinct from mast cell degranulation.

Intermediate epithelium

In the nasopharynx, the larynx, the anal canal and the auditory tube, the "intermediate epithelium" occupied the transitional zone between the ciliated (or nonciliated) columnar epithelium and the stratified squamous one. The intermediate epithelium showed gradations ranging from stratified low-columnar through stratified cuboidal to stratified squamous type. It was suggested that the intermediate epithelium showed the various stages of the epithelium transforming from the columnar to the squamous epithelium, and that the basal cells of the columnar epithelium served as the germinal layer of the transformation.

Ultrastructural and histochemical study of the motor end plates of the intrinsic laryngeal muscles in amyotrophic lateral sclerosis

Motor end plates of the intrinsic laryngeal muscles in amyotrophic lateral sclerosis (ALS) were examined light and electron microscopically. Light microscopically, typical neurogenic changes such as small angulated fibers and grouped atrophy were found in the intrinsic laryngeal muscles. Acetylcholinesterase (AchE) activities of the neuromuscular junctions (NMJ) of many fibers in ALS were decreased as compared with those of the controls. Some end-plate areas on each fiber detected by AchE histochemistry were larger than those of the controls. Ultrastructurally, muscle fibers in ALS specimens showed several changes; increased number of lipofuscin granules and/or nuclei, numerous mitochondria, and disappearance of the myofilaments. The NMJ also showed various degrees of structural changes. Some NMJ appeared almost normal. Others showed the absence of nerve terminals and Schwann cells covering the former junctional sites. Their primary synaptic clefts were flattened, and the secondary synaptic clefts were relatively well preserved. On occasion, several small nerve terminals were seen on the severely distorted postsynaptic folds, suggesting regenerative findings. In severely degenerated muscle fibers, the NMJ could not be found.

[Retrospective analysis of selected tumor markers (p53, PCNA, Ki67; DNA ploidy) and ultrastructure in patients with larynx carcinomas]

A comparison was made of the staining intensities of selected immunohistochemical proliferating antigens (p53, PCNA, Ki67), DNA flow-cytometry and ultrastructures of neoplastic cells from 120 cases of laryngeal cancers. Clinically very advanced tumors were in the majority (T3, 43%; T4, 18%). A 5-grade scale was adopted to evaluate the level of immunohistochemical staining of the carcinoma cell nuclei. Positive staining was obtained in 70% for p53, 57% for Ki67 and 80% for PCNA. Sixty-two percent of the cases were DNA-diploid and 38% DNA-aneuploid. The DNA-diploid carcinomas were accompanied by enlargement of the cell nuclei, preservation of wide margins of nuclear heterochromatin, enlargements of the nuclear areas and increases in the number of nuclei. In the aneuploid-polyploid cancers the nuclei had a substantial polymorphism, with large cleaved nuclei showing significant variations in size and having a nuclear envelope. A frequent finding was euchromatization of chromatin. Dense chromatin appeared in the form of small clumps spread over the whole area of these irregular nuclei. Enlargement and activation of nucleoli were found. There was a positive (chi-square) correlation between T- and N-stage and immunohistochemical staining. There was also a positive correlation in staining intensity between p53, Ki67 and PCNA markers and strong correlation between these markers for proliferative activity and the degree of aggressiveness of a tumor.

Functional and clinical anatomy of the posterior insertion of the human vocal ligament

The suggested methods of the formation of intubation granuloma as well as carcinoma invasion in the area of posterior vocal ligament insertion have been controversial. One reason for divergent opinions is possibly based on different judgements of morphology in this region. The present study analyzed structures of the vocal ligament and vocalis muscle insertion at the vocal process by means of histological, immunohistochemical and electron microscopic methods. Investigations were performed in three planes on the vocal cords of 22 men and 19 women (aged 21-97 years). Inside the insertion zone of the vocal ligament at the vocal process three structures could be distinguished: hyaline cartilage at the base of arytenoid cartilage, elastic cartilage at its apex and the posterior elastic nodule in front of them. No perichondrium could be seen around the elastic nodule. In elastic nodules type I and type III collagen fibrils as well as elastic fibers formed a scissor-like meshwork around large fibroblasts. The vocalis muscle inserted at the perichondrium in the lateral part of the arytenoid skeleton by short tendons. At the insertion zone blood vessels of the vocalis muscle penetrated the perichondrium and reached the cartilaginous matrix. At the beginning of osteogenesis, the blood vessels connected with intraosseous blood vessels of the arytenoid. Connective tissue cells of the insertion zone and extracellular matrix components formed by these cells fulfilled a biomechanical function by equalizing the different elastic moduli of tendon, cartilage or bone. The lack of perichondrium around the lengthened posterior elastic nodule made formation of intubation granulomas caused by perichondritis in this area impossible. Loosened perichondrium or periosteum in the area of the insertion of the vocalis muscle at the vocal process, ossification and associated vascularization of the arytenoid skeleton permitted invasion of carcinomas into the arytenoid.

Innervation of taste buds in the canine larynx as revealed by immunohistochemistry for the various neurochemical markers

The distribution and innervation of the canine laryngeal taste buds were observed using immunohistochemistry with antibodies against protein gene product 9.5 (PGP 9.5) and neurofilament protein (NFP). We also observed the immunohistochemical distribution of serotonin, tyrosine hydroxylase (TH) and various neuropeptides including calcitonin gene-related peptide (CGRP), substance P (SP), vasoactive intestinal peptide (VIP), galanin, methionine enkephalin (ENK) and neuropeptide Y (NPY). The taste buds in the canine larynx were densely distributed in the mucosa at the basal portion of the epiglottis and cuneiform process of the arytenoid cartilage. The taste cells were immunoreactive for PGP 9.5 and serotonin. The nerve fibers with immunoreactivity for PGP 9.5 in the taste buds were observed in the perigemmal region and intra- and subgemmal plexuses, and these were classified into two types based on their diameter. The thick nerve fibers corresponded to the fibers immunoreactive for NFP, while the thin nerve fibers corresponded to the fibers immunoreactive for TH and various neuropeptides. Numerous nerve fibers immunoreactive for SP and CGRP were observed in the perigemmal region, and intra- and subgemmal plexuses. A few galanin- and ENK-immunoreactive nerve fibers were also observed in the taste buds, whereas NPY-immunoreactive nerve fibers were noted beneath them. All peptide-containing fibers except for VIP-immunoreactive nerves were situated in the subgemmal regions. In conclusion, the multiple innervation to the laryngeal taste buds were documented. Thick nerve fibers are likely to be irritant receptors, while thin varicose nerve fibers seem to regulate taste buds themselves. The laryngeal taste buds may be among the important structures which are sensitive to exogeneous chemical and/or mechanical stimuli, for the protection of the airway and the regulation of the respiratory function.

Clinicopathological consultation. Lymphoepithelial carcinoma of the larynx hypopharynx, and trachea

Lymphoepithelial carcinoma of the larynx, hypopharynx, and trachea is a rare neoplasm composed of large, poorly differentiated, nonkeratinized cells intermingled with small nonneoplastic lymphocytes and plasma cells. It is histologically similar to its more common counterpart occurring in the nasopharynx. In contrast to nasopharyngeal carcinoma, most cases have not been associated with Epstein-Barr virus (EBV), although rare cases have been reported to be EBV-positive. The diagnosis often requires immunohistochemistry or electron microscopy for confirmation. The neoplasm seems to behave in a fashion reminiscent of nasopharyngeal carcinoma. Lymph node metastasis occurs in the majority of patients, and eventual visceral dissemination occurs in one fourth. Radiotherapy is the main treatment for the primary tumor and regional metastases, but chemotherapy is indicated for more advanced disease. The initial stage is the primary determinant of prognosis. Death from disease occurs in about one third of patients.

[Parapharyngeal carcinoma of the larynx: current clinical and pathological aspects and reports of a clinical case]

Schwannomas (neurilemmomas) are benign tumors of the nerve sheath arising from the Schwann cells in the neural sheath of cranial and spinal nerves. The most frequent sites are the peripheral nerves of the head and neck and the flexor surfaces of the upper extremities. Parapharyngeal schwannomas are rare, which makes them interesting for ear, nose and throat specialists. A new case of schwannoma of the parapharyngeal space is reported. Our experience with the clinical management and surgical treatment of cervical schwannomas is discussed and the literature is reviewed.

[Malignant fibrohistiocytoma in otorhinolaryngology. Review of two cases]

Fibrohistiocytomas are soft-tissue tumors of histiocytic origin that have a variety of histological patterns. Although cases of malignant fibrohisticytoma (MFH) of the head and neck have been reported with increasing frequency in recent years, they can be considered rare. However, they probably are more frequent than thought because of the different designations that the disease has received and confusion among clinicians and pathologists regarding these tumors. We report two cases of MFH of the tonsil and larynx, respectively. The histopathological diagnostic criteria, therapeutic indications, and prognosis evaluation are described.

Morphological study of the vagal afferent nerve endings in the laryngeal mucosa of the dog

The afferent nerve endings in the laryngeal mucosa of the dog were investigated by immunohistochemical staining specific for neurofilament protein of whole-mount preparation. In the laryngeal mucosa, two kinds of nerve endings, namely, laminar and glomerular endings, were observed. The laminar endings were distributed on the laryngeal side of the epiglottis, the mucosa overlying the arytenoid cartilage and the vocalis muscle. The laminar endings were 100-350 microns long and 60-200 microns wide. Some axons gave rise to a single ending while others continued to two endings. The terminal portions were round, oval or triangular in shape, and occasionally had an immunopositive rim with a negative center. Cryostat sections revealed that the laminar endings were located immediately beneath the laryngeal epithelium. The endings were flattened and extended in two dimensions. The glomerular endings could be divided into two subtypes, large ones and small ones. The large ones were 150-250 microns long and 90-200 microns wide, and they were distributed in the mucosa of the intercartilaginous part of the glottis and the laryngeal side of the epiglottis. Several nerve fibers were gathered in the subepithelial region and arranged in a glomerular pattern. In some large glomerular endings, the terminal portions formed laminar arborizations. The small glomerular endings were 100-200 microns long and 40-120 microns wide, and their distribution was restricted to the mucosa of the corniculate process of the arytenoid cartilage. They were simple in terms of shape and were also located in the subepithelial region. Some small endings were accompanied by mucosal protrusions and were located near taste buds. Dogs that had been subjected to surgical denervation of the internal branch of the cranial (superior) laryngeal nerve suggested that both the laminar and the glomerular endings were mainly derived from this branch of ipsilateral side.

[Phyolaryngocele: a case report and review of literature]

A case of pyolaryngocele presented as a lateral cervical mass that produced acute dyspnea requiring tracheotomy. The diagnosis was by direct laryngoscopy, which revealed outflow of purulent material with pressure on the tumor, and was confirmed by CT. Broad-spectrum antibiotic treatment was given and the pyolaryngocele was excised by lateral extramucosal tyrotomy. The literature on laryngocele and pyolaryngocele was reviewed.

[Expression of proto-oncogene bcl-2 in squamous cell carcinoma of the larynx]

Apoptosis, or programmed cell death, is responsible for deleting cells in normal tissues to maintain homeostasis after DNA damage. Apoptosis has several physiological inhibitors, one of the most important being the proto-oncogene bcl-2. An immunohistochemical study was made of bcl-2 expression in 25 squamous cell carcinomas of the larynx, in laryngeal mucosa distant from the primary neoplasm, and in lymph node metastases. The relationship between bcl-2 expression and various clinical and pathological parameters was investigated. Bcl-2 was detected in 40% of primary tumors and in 71% of lymph node metastases; it seems to be a late event in laryngeal malignant transformation. We found no statistical association between bcl-2 expression and most of the clinical and pathological parameters examined. Only tumor differentiation was related to bcl-2 expression, bcl-2 positive tumors being moderately or poorly differentiated (p < 0.02).

[Granular cell tumor of the larynx]

Granular cell tumor is an unusual growth of probably neuroectodermal histogenesis, first reported by Abrikossoff in 1926 with the name of myoblastoma. Of the about 1200 cases reported since, the 50 percent were found in the head and neck. Of second mentioned 10 percent had a laryngeal sitting. A case of glottic granular cell tumor surgically removed with free borders is presented. Bibliographical review.

[Scanning electron microscopic observation of the three-dimensional structure of laryngeal carcinoma using freeze-cracking method]

OBJECTIVE

To investigate the relation between the morphology and the biological characteristics of laryngeal carcinoma.

METHODS

The freeze-cracking method was used to examine 126 specimens of the larynx under scanning electron microscope (SEM). The specimens were obtained from 12 patients suffering from laryngeal cancer and 4 patients with normal larynx.

RESULTS

(1) In the normal larynx, the squamous-cell epithelium showed marked keratinization and the intracellular bridges were clear and regular. (2) In areas adjacent to cancer, the structure of the squamous-cell epithlium could be identified, but the cells were deranged and paramorphic. (3) There were two types in the marginal area of the carcinoma. Along the areas adjacent to cancer, infiltrating lymphocytes were usually observed and the surface of the lymphocytes had many leading lamella.

CONCLUSION

The results indicate that the three-dimensional observation with SEM using the freeze-cracking technique is helpful for studying the relation between morphology and biologic characteristics of laryngeal carcinoma.

Autologous fat injection for unilateral vocal fold paralysis

This study evaluates the efficacy of autologous fat injection for medialization of the paralyzed vocal fold. In 21 patients with unilateral vocal fold paralysis, autologous abdominal fat was injected into the thyroarytenoid muscle to achieve medialization. All patients were followed up with serial videolaryngoscopy and voice evaluation. At 2 months' follow-up, the voice was judged to be excellent in 10 patients, slightly breathy but significantly better than the preoperative voice in 6 patients, and markedly breathy in 4 patients. At 3 to 4 months' follow-up, of the 10 patients with excellent results, 5 maintained an excellent voice, 3 had developed slight breathiness, and 1 had developed severe breathiness. Long-term (6 to 12 months) results were available in 11 patients, and all of them maintained the same voice quality that was noted during the 3 to 4 months' examination. Magnetic resonance imaging of the larynx was obtained in 7 patients at intervals ranging from 1 to 7 months and compared to the baseline scan obtained at 1 week postoperative to assess the amount of fat remaining in the muscle. The images showed fat volume to persist, but a decrease in the fat signal was observed over time. The results suggest that the duration of medialization with autologous fat is variable, but appears to last at least 2 to 3 months. This loss of volume after 3 months seems to be due to absorption of the fat and possibly muscle atrophy. Autologous fat injection is relatively safe and easy to perform, and is an ideal method of temporary vocal fold medialization in patients in whom return of vocal fold function is expected.

[Laryngeal cancer and angiogenesis]

Angiogenesis is required for the growth of solid tumors which, in avascular condition, are limited to 2-3 mm3 volume. The switch to the angiogenic phenotype allows new vessels to converge upon the tumor, growth to proceed at an exponential rate and metastasis diffusion. The evaluation of tumoral angiogenesis has been proposed to be an independent prognostic marker of behaviour of some solid tumors: it has been demonstrated that, in some types of carcinoma (breast, prostate, lung, etc...), an intense vascular proliferation correlates with the aggressiveness of the disease. However in malignant melanomas and colorectal carcinomas, there are conflicting results on the correlation between angiogenesis and the progression of the cancer. There are also conflicting data on the role of microvessels count (MC) in the management of head and neck cancer. Despite a large number of studies, at the present, there are not biological or molecular markers available to predict consistently the outcome of the patients with laryngeal squamous cell carcinoma (LSCC). In fact the prognosis of this tumor has been mainly based, up to now, on a number of clinico-pathological parameters, especially localization, tumor extent and nodal involvement. The aim of this study has been to compare MC inside LSCC with disease free survival, grading, pT, pN and pathological stage. We investigated the relevance of the number of microvessels in the peritumoral stroma of 68 LSCC (only Caucasian males, age 35-70 years), classified according to UICC/1987 randomly selected (33 classified in clinical stage I e II and 35 in clinical stage III-IV). All patients have been surgically treated and pN + cases have been also submitted to radiotherapy. The follow-up was 60-84 months. The vascular density was assessed according to Horak et Al. with an immunohistochemical method using JC70 monoclonal antibody (CD31; Dako, Astrup, Denmark). Univariate analysis showed that MC, pT, pN, Pathological Stage and grading were correlated with the disease-free survival. A MC < 120/mm2 was predictive for a high survival index; in contrast a MC > 150 mm2 were associated with relapse. Furthermore, multivariate analysis demonstrated that MC was the only independent predictor for the disease free survival. Our findings demonstrate that in LSCC, MC is the first measurable biological parameter which is significant for evaluating the disease free-survival. Therefore, MC in LSCC is crucial in the prognosis and in the choice of a more aggressive management of the disease, including the possible treatment with antiangiogenic compound.

Laryngeal lymphoma derived from mucosa-associated lymphoid tissue

Extranodal lymphomas account for as many as 40% of non-Hodgkin's lymphomas, and most arise in the gastrointestinal tract, but other mucosal organs may be involved, especially the upper aerodigestive tract. Low-grade B-cell lymphomas arising in the gastrointestinal tract and other mucosae have been found to recapitulate the structure and cytologic features of mucosa-associated lymphoid tissue (MALT). Histologically low-grade MALT lymphomas are characterized by centrocyte-like B-cells with a phenotype similar to that of so-called marginal zone B-cells. Tumors evolving from MALT are generally rare among lymphomas of the upper aerodigestive tract, but a few cases of laryngeal lymphomas derived from MALT have been reported. Primary MALT lymphoma of the larynx should always be considered in tumors with histopathologic features of low-grade B-cell lymphoma, or so-called pseudolymphoma.

Immunohistochemical characterization of benign laryngeal lesions

It has been proposed that laryngeal nodules and polyps represent injury to the basement membrane zone of the vocal fold. Repeated trauma from shearing forces produced by excessive or abusive phonation leads to basement membrane zone disruption and thickening. This thickening, along with poorly understood vascular changes, creates the characteristic clinical appearance of the vocal nodule or polyp. As such, to better understand vocal fold nodules it is imperative to characterize the extracellular matrix in this area of injury. Secondary to the small size and relatively acellular nature of these lesions, hematoxylin and eosin (H & E) preparations of histologic material are unsatisfying. A previous study examined this area with immunohistochemical techniques to better characterize its contents. The report, however, contained little information with regard to the clinical appearance of the lesions prior to excision. Therefore, we were prompted to review histologic material from 31 patients who underwent microsurgical excision of 41 benign lesions, vocal nodules (4), polyps (19), polypoid corditis (4), and cysts (14) with immunohistochemical techniques to characterize the patterns of fibronectin and collagen type IV within these lesions. Normal human vocal folds were stained for control. All material was correlated with the H & E preparations and the clinical diagnosis. Collagen type IV and fibronectin appeared present in relatively abnormal patterns in the areas adjacent to the lesion. This study validates earlier results. In addition, correlation with clinical data allows association of immunohistochemical staining patterns with clinical diagnosis.

Isolated non-Hodgkin's malignant lymphoma of the larynx presenting as a large pedunculated tumor

This paper presents a case of non-Hodgkin's lymphoma (NHL) of the larynx. The patient was an 86-year-old man who complained of foreign-body sensation and dysphagia. Laryngoendoscopic examination revealed a large pedunculated mass arising from the left aryepiglottic fold. A diffuse, large, B-cell-type NHL was diagnosed histopathologically. The patient was treated with combination chemotherapy, resulting in complete clinical remission. The clinicopathological features of this case have been described and compared with previously reported cases.

[The use of x-ray microanalysis and transmission microscopy in studies of the chemical composition and ultrastructure of the microregions of precancerous tissues of the larynx]

The authors have presented the results of studies concerning the changes of chemical composition and ultrastructure of tissue microregions at patients with laryngeal precancerous states. Microanalytical studies were made using X-ray JEOL JSM 35 microprobe analyser. The chemical composition of laryngeal precancerous tissue taken from the patients and a control group was estimated. The results of studies were verified using X-ray PHILIPS XL-30 microanalyser. Studies of tissue ultrastructure changes were conducted using JOEL JEM 100 XC transmission microscope. Some heavy metals like, lead, cadmium, nickel, iron, copper and caesium were found in the tissue from larynx precancerous state. Further more, in analysed biologic material there were noticed various degenerative changes within stratified squamous epithelium.

[Paraganglioma of the larynx]

A rare case of a large paraganglioma of larynx was presented. The whole tumor was removed by partial laryngectomy.

[p53 oncogene in the laryngeal cancer]

Cancer is a genetic disease and the development of the techniques of molecular biology in recent 10 years contributed to the new understanding of neoplasmatic process. The mutations of gene p53 became one of the most common abnormality in human cancer. The aim of this research was to mark oncoprotein p53 in 120 cases of larynx cancer and the correlation of its appearance with clinical and histopathological parameters. The evaluate the degree of immunohistochemical staining of cell nuclei a 5 degree scale was adopted. The positive staining of cell nuclei was observed in 70% of cases. Positive correlations based on a chi-square test was observed between p53 and T and N as well as between p53 and the degree of histological differentiation.

Distribution of immunocompetent cells in various areas in the normal laryngeal mucosa of the rat

The larynx can be divided into a supraglottic, a glottic and a subglottic area, each serving different functions. In many cases of laryngitis the site of infection is located in one area, leaving other areas unaffected. It seems reasonable to speculate that the underlying cause of the heterogeneous infection pattern in the larynx is the different processing of infectious agents. Therefore, the number and distribution of granulocytes, macrophages, dendritic cells, natural killer cells and T and B lymphocytes in the normal laryngeal mucosa of young rats were studied. The results show that, with the exception of granulocytes, all subpopulations were present in different numbers. Many macrophages and dendritic cells but only a few natural killer cells and T and B lymphocytes were located in the mucosa. Dendritic cells, natural killer cells and T and B lymphocytes were rarely present in the vocal fold area, whereas in the subglottic area they were present in high numbers. Thus, differences in the composition of immunocompetent cell populations between laryngeal areas were detectable.

[A case of the laryngeal fibroma]

The authors describe a case of very rare neoplasm fibroma proper in the region subglottic of larynx. Operative treatment by tracheostomy, thyroidotomy and complete extirpation of the tumor.

[Moderately differentiated neuroendocrine carcinoma of the larynx]

We present a case of moderately differentiated neuroendocrine carcinoma of the larynx. These tumors represent 0.6% of all laryngeal carcinomas. Histological diagnosis requires the use of immunohistochemical methods, the tumoral cells presenting positivity for epithelial markers (cytokeratin) and neuroendocrine markers (chromogranin). Clinically, their location is supraglottic and they affect mainly males between the 6th-7th decades of life. The prognosis is better than that of squamous carcinoma or adenocarcinoma. The differential diagnosis must be made with granular cell tumor and paragangliomas.

[Mucoepidermoid carcinoma of the larynx. A case report]

We report a case of laryngeal mucoepidermoid carcinoma that was diagnosed in the Hospital Miguel Servet of Zaragoza. The unusual tumor site and difficult diagnosis were notable and, above all the fatal outcome after local recurrence and metastasis in spite of good overall prognosis.

Stratified squamous epithelia produce mucin-like glycoproteins

The stratified squamous epithelia of the ocular surface, larynx, and vagina are mucus-coated epithelia, apices of which are subject to abrasive pressure from epithelia-epithelia interactions from eyelid, vocal cords, or vaginal folds, respectively. Mucus coats on these epithelia have generally been considered to be derived from the specialized mucin-producing cells embedded either in the epithelia or in adjacent tissues. Here we report the isolation, partial characterization, and cellular localization of a mucin-like glycoprotein produced by these stratified epithelia. In all three epithelia, the mucin-like molecule is present on cytoplasmic vesicles in subapical cells. As cells differentiate to their apical-most position adjacent to their mucus coat, the mucin-like molecule moves to the cell membrane where it is particularly prominent on microplicae folds. Lectin affinity chromatography was used to isolate the molecule from rat vaginal and corneal epithelium. Isolated material was approximately 60% carbohydrate and 40% protein. The major monosaccharide was N-acetylgalactosamine with lesser amounts of N-acetylglucosamine, galactose, mannose, xylose and fucose. Amino acid analysis demonstrated the predominant amino acids to be glycine, serine, threonine and proline. These data plus PAS and Alcian blue binding to the isolate indicate a mucin-like glycoprotein.

Neuroendocrine neoplasms of the larynx. Importance of the correct diagnosis and differences between atypical carcinoid tumors and small-cell neuroendocrine carcinoma

Findings in the present study have confirmed that the diagnosis of neuroendocrine tumors of the larynx (NETL) requires that a panel of neuroendocrine markers and electron microscopy be performed. This means that the clinician must be aware of the clinical presentations of such patients and should send fresh biopsy specimens to the clinical laboratory for optimal tissue studies. As shown in this study, the possibility of misdiagnosis of an atypical carcinoid tumor (ACT) is rather high. In establishing a diagnosis, a part of the material should be fixed for conventional histology, a part for immunohistochemistry and a part for electron microscopy. The correct diagnosis of NETL is obviously of great importance for subsequent treatment and prognosis. Patients with the diagnosis of ACT of the larynx require surgical treatment. Our findings also show that small-cell neuroendocrine carcinomas of the larynx should be considered to be a disseminated disease at initial presentation. A metastatic workup is necessary, but radical surgical procedures should be avoided. The combination of radiotherapy and chemotherapy is always indicated.