Non-keratinized Stratified Squamous Epithelium Research Articles

Biological and Adhesive Properties of an Autologous Protein-Based Fibrin Sealant for Ophthalmological Applications.

The aim of this study was to evaluate the biological and adhesive properties of a new autologous sealant based on plasma rich in growth factors (PRGF), named E-Sealant. Conventional PRGF and a commercial fibrin sealant (Tisseel) were included as controls. The hematological and protein content of E-Sealant was determined. Its bioactivity and biocompatibility were tested for human keratocytes (HKs). To evaluate its adhesion and regenerative capacity, E-Sealant was used on an animal model of conjunctival autograft surgery and compared to Tisseel. E-Sealant presented a high growth factor content with levels similar to those of conventional PRGF. E-Sealant induced proliferative and migratory activity on HK cells equivalent to PRGF. Although autologous membranes induced the proliferation of HKs, cells cultured over Tisseel did not adhere nor proliferate. HK cells showed increased number and flattened morphology over PRGF and E-Sealant compared to scarce and round-shape cells detected in Tisseel. Conjunctival autograft glued with E-Sealant adhered successfully, whereas Tisseel application formed irregular clots. During follow-up, both adhesives showed good integration and no dehiscence. However, Tisseel-treated samples presented slightly increased hemorrhage and inflammation. In contrast to Tisseel, E-Sealant-treated autografts presented a continuous layer of non-keratinized stratified squamous epithelium. Inflammatory infiltrates were minimal in E-Sealant-treated conjunctiva, whereas the Tisseel group showed noticeable immune reactions. Unlike Tisseel-treated grafts, E-Sealant presented low immunoreactivity for smooth muscle actin (SMA), suggesting decreased fibrotic tissue formation. E-Sealant presents optimal biological and adhesive properties suitable for use as an ophthalmic glue, with regenerative purposes superior to commercial fibrin sealants. Our study analyzed the characterization and biological activity of a new autologous fibrin sealant in ocular surface cells and in an animal model in which the adhesive and regenerative properties of the fibrin sealant were evaluated.

Histochemical analysis, smooth muscle immunolocalization and volumetric density of the elastic system fibres of the ostrich (Struthio camelus) phallus.

There are few scientific reports on the histology of the phallus of ratite birds. The aim of this study was to conduct a histochemical analysis to determine the distribution of smooth muscle cells and the volumetric density (Vv) of the fibres of the elastic system in the ostrich phallus. Adult ostriches, 14 months old, were used. The phalluses were fixed in Bouin's solution and then transferred to a buffered formalin solution. They were then processed using standard histological stains for paraffin and slices were obtained. The following techniques were performed: HE, Picrosirius red, Alcian Blue at pH 1.0 and 2.5. The Periodic acid-Schiff reagent and Weigert's Resorcin-Fuchsin with previous oxidation were performed. The M42 test system was used to quantify the elastic system fibres. For immunohistochemical analysis, an anti alpha smooth muscle actin monoclonal antibody was used. The surface of the phallus is covered by a non-keratinized stratified squamous epithelium, which becomes stratified cylindrical in the region of the spermatic sulcus. No glands associated with the connective tissue were observed. The Vv of the elastic system fibres was 4.75%. Smooth muscle cells were visualized only in the walls of blood vessels through immunostaining, with an absence in the lymphatic sinuses. Despite similarities with other birds, such as the presence of a fibrous external axis, a lymphatic core, and a spermatic groove, the ostrich phallus shows marked differences, including the absence of an elastic core, a non-keratinized lining epithelium, and the absence of glands throughout its extension.

Fence Technique: Reconstruction on the Aesthetic Zone after Cyst Enucleation—Case Report

Odontogenic cysts can lead to bone destruction that can hamper the dental implant placement in the ideal 3D position. Different biomaterials and techniques that allow bone regeneration are described in the literature, each with its advantages and disadvantages. This clinical case with 18 months of follow-up aims to show the enucleation of an odontogenic cyst following the guided bone regeneration with the fence technique, which allows the placement of the dental implants in the ideal 3D position, reducing morbidity and the number of surgeries. It involved a fifty-year-old male patient with a cyst in the second sextant who needed implant rehabilitation. During the first surgery, the odontogenic cyst (proven by histological analysis where there was reported a non-keratinized stratified squamous epithelium) was enucleated and a guided bone regeneration using the fence technique was performed. The fence technique combines the xenograft, the collagen membrane and an osteosynthesis plate that is molded and fixed to the intervention area to ensure sufficient space for bone tissue regeneration. After six months, two dental implants were placed in the region of tooth 11 and 21, then rehabilitated nine weeks later. The fence technique guaranteed the recovery of the bone morphology and the placement of the dental implants in the ideal 3D position. This technique allows for the handling of complex cases, avoiding the need of autologous bone.

Morphological and histological study of the third eyelid in hedgehogs.

The third eyelid in animals plays an important role in maintaining eye health. Like other organs of the body, the third eyelid can be afflicted with minor or deep injuries, inflammations or even tumours in different species. The current study investigates the morphological and histological characteristics of the third eyelid in hedgehogs. Eight healthy adult hedgehogs (male and female) weighing 500-700g were included in this study. Deceased animals were used for this study. Few incisions were applied around the eye and eye socket. The eye was removed, and the samples were fixated in 10% formalin solution to prepare for the histological study. To evaluate the morphological characteristics, the third eyelid was placed in 2% and 4% formalin solutions. The histological study revealed that the third eyelid cartilage is an elastic cartilage and includes chondroblasts and chondrocytes. The cells of this cartilage were either distributed individually or in isogenic groups. The bulbar and palpebral surfaces of the eyelids were devoid of any glands and were covered with a non-keratinized stratified squamous epithelium. The anatomical examination also showed that the third eyelid had an oval-shaped cartilage. Comparing the results of this study with reports on other rodents showed that the morphological and histological structure of the cartilage in the hedgehog's third eyelid is mostly like the structure of this tissue in Indian mongoose (Herpestes javanicus).

Morphology of the soft palate and palatine tonsil of the goat (Capra hyricus).

The present study was carried out to study the morphology of the goat's soft palate and palatine tonsil by gross anatomy, morphometry, light and scanning electron microscopy (SEM). Twelve heads of normal adult (18-24 months) apparently healthy goats of both sexes were collected from local commercial slaughterhouses in Qena Governorate, Egypt. The oral cavity was dissected, and samples were collected for both light and SEM. The soft palate of the goat formed the caudal continuation of the hard palate. It was relatively short, it extended from the level of the caudal border of the last upper molar tooth to terminate caudally against the base of the epiglottis. The oral mucous membrane of the soft palate was covered by non-keratinized stratified squamous epithelium. The lamina propria and submucosa contained connective tissue fibers, diffuse and nodular lymphatic tissue, striated muscle fibers, and a large number of mucous and serous palatine glands. By SEM, the ventral surface had several rounded openings occupied by flower-like structures. These openings represented the entrances to the palatine glands. The palatine tonsil was large and protruded from a fossa in the lateral wall of the oropharynx. It had 2-3 elongated irregular openings that lead to the underlying crypts. These crypts were well-developed and lined by non-keratinized stratified squamous epithelium. The epithelium of the tonsillar crypts directly covered lymphoid tissue and was infiltrated by lymphocytes. Tonsillar glands of pure mucous type were demonstrated. In conclusion, the study provides the basic morphological features of soft palate, as well as the palatine tonsil of the goat by gross observation, light and SEM. The palatine tonsils of goat were well-developed with extensive crypt system, suggesting their essential role in the immunological response against antigens that enter through the oral cavity. The current findings may be useful to understand the role of the palatine tonsil in immunity and disease pathogenesis. RESEARCH HIGHLIGHTS: The study reported the basic morphological features of soft palate and palatine tonsil of goat. The ventral surface of the soft palate had several rounded openings occupied by flower-like structures. The palatine tonsils of goat were well-developed with extensive crypt system. The findings might help to understand the role of the palatine tonsil in immunity and disease pathogenesis.

Macroscopic and histological aspects of the pharynx and larynx of the giant anteater (Myrmecophaga tridactyla Linnaeus, 1758).

Giant anteater (Myrmecophaga tridactyla) is an endangered species that resides in much of Latin America, but it has been losing its habitat, especially in the Cerrado biome, where it constantly suffers traumas resulting from fires and roadkill. The anatomical knowledge of structures of the respiratory system is important for a better morphophysiological understanding of the species. Thus, this study aimed to perform the macroscopic and histomorphological description of the pharynx and larynx of the giant anteater. Twelve adult giant anteaters were used, three of them fixed in buffered formalin for further dissection and pharynx and larynx macroscopic analysis of structures. From the other animals, samples of the pharynx and larynx were collected and prepared for histological evaluation under optical microscope. Macroscopically, their pharynx and soft palate are extensive, and the anatomical location of these structures and the larynx differs greatly from that described in other species. The larynx, although more caudal, was similar to that of other animals. Histologically, the epithelium of these regions varied between the pseudostratified ciliated columnar and the non-keratinized stratified squamous epithelium. Laryngeal cartilages were composed of elastic (epiglotti) and hyaline cartilages (arytenoid, cricoid and thyroid cartilage), with an ossification process and glandular clusters around the hyaline cartilage. The distinct anatomical location of the pharynx and larynx of Myrmecophaga tridactyla is the main macroscopic finding of this study, besides the length of the pharynx and soft palate of these animals.

Clinical Signs of Kawasaki Disease from the Perspective of Epithelial-to-Mesenchymal Transition Recruiting Erythrocytes: A Literature Review

Kawasaki disease (KD) is a systemic vasculitis affecting children younger than 5 years of age. Early period in life is marked by rapid somatic growth with cell proliferation and immaturity of the immunity with dominant innate immune system. Coronary complications in KD are the most common acquired heart disease in children, yet the diagnosis of KD still depends on the clinical diagnostic criteria. Glossy red lips and conjunctival injection are characteristic signs enabling pediatricians to make the initial diagnosis of KD; however, little is known why these are so characteristic. The diagnostic criteria of KD seem to be scattered in seemingly irrelevant body systems such as the eyes, lips, skin, and heart. KD is classified as a connective tissue disease. Recently, red blood cells (RBCs) have emerged as important modulators in innate immune response. RBCs are reported to participate in extracellular matrix remodeling and upregulating matrix metalloproteinase (MMP) expression in dermal fibroblasts. Also, fibroblast growth factors and microRNAs associated with fibrosis are drawing attention in KD. The cardinal signs of KD appear at the border of muco-cutaneous junction. Head and neck regions are abundant in tissues undergoing epithelial-to-mesenchymal transition (EMT). Interstitial carditis and valve insufficiency as well as coronary arterial lesions may complicate KD, and these lesions present in tissues that originated from epicardial progenitor cells by EMT. Having reviewed the recent research on KD, we presume that the signs of KD present at borders between keratinized and non-keratinized stratified squamous epithelium where the EMT is still ongoing for the rapid somatic growth where RBCs are recruited as an innate immune response and to prevent excessive fibrosis in mucosa. KD presents scarcely in adults with somatic growth and immune maturation completed. In this review, we attempted to explain the reasons for the clinical manifestations of KD and to search for a link among the diagnostic clues in the perspective of EMT during the somatic growth and immune system maturation in children with KD.

Morphological tongue and palate characterizations in Trachemys adiutrix (Vanzolini, 1995) turtles.

Morphological studies on the oropharyngeal cavity of turtles are an interesting tool in understanding evolutionary processes associated with feeding habits. There is paucity of morphological information on the oropharyngeal cavity of the Trachemys adiutrix turtle. Thus, the aim of this study was to describe the tongue and palate morphology of T. adiutrix to establish a standard model for the species, providing information that may improve knowledge on the species feeding habits. Gross dissection, light microscopy and scanning electron microscopy assessments of 11 specimens were carried out. The tongue of T. adiutrix is triangular with a slightly rounded apex and broad base and lingual papillae widely distributed throughout the entire dorsal surface. The palate is composed of bony structures, displaying a triangular apex with one pair of choanae and palatine raphe that begin in the middle region, dividing the two openings. The body was elongated and smooth. The root was wrinkled and opened into the oesophagus. The tongue was lined by non-keratinized stratified squamous epithelium, rich in mucous cells and a large number of different-shaped papillae and taste buds. The palate was mainly lined by a pseudostratified cylindrical ciliated epithelium rich in mucous cells. In conclusion, the tongue and palate characteristics of T. adiutrix include evidence that these animals are semiaquatic, displaying morphological characteristics associated with aquatic and terrestrial trophic ecology, similar to that observed in other semiaquatic and terrestrial chelonian species.

Morphological examination and scanning electron microscopy of the barn owl's (Tyto alba) tongue.

The beak structure changes according to the feeding patterns of birds. Further, the morphological and histological structures of their tongues vary. Therefore, the current study aimed to perform macroanatomical and histological examinations and scanning electron microscopy of the barn owl's (Tylo alba) tongue. Two dead barn owls were brought to the anatomy laboratory and were used as study material. The tongue of the barn owl was long, triangular-shaped with a bifurcated tip. There were no papillae in the anterior 1/3 of the tongue, and the lingual papillae were shaped toward the back. The radix linguae were surrounded by a single row of conical papillae. Irregular thread-like papillae were found on both sides of the tongue. The salivary gland ducts were on the lateral margin of the corpus linguae and the dorsal surface of the radix linguae. The lingual glands were in the lamina propria near the stratified squamous epithelium layer of the tongue. The dorsal surface of the tongue comprised non-keratinized stratified squamous epithelium, and the ventral surface and caudal part of the tongue had keratinized stratified squamous epithelium. Hyaline cartilages were detected in the connective tissue immediately below the non-keratinized stratified squamous epithelium on the dorsal surface of the root of the tongue. The study results can contribute to the current knowledge on the anatomical structure of birds. Further, they can be useful in managing the barn owl when used as companion animals and in research activity.

8866 Vaginoplasty Using Lyophilized Nile Tilapia Fish Skin in Sex Reassignment Surgery in 35 Transgender Women

<h3>Study Objective</h3> describe the use of LNTFS (Lyophilized Nile Tilapia Fish Skin) as graft for the lining of the neovaginal canal in neovaginoplasty for transgender women. <h3>Design</h3> Transversal study from August 2019 to December 2020. <h3>Setting</h3> N/A. <h3>Patients or Participants</h3> 35 transgender women older than 18 years. <h3>Interventions</h3> First of all, a bilateral orchiectomy followed by ventrally urethra opening, creating a new urethral meatus and a mucosal flap that will be attached to the base of the clitoris. For the vaginal lining, a xenograft tube composed of penile skin plus LNTFS was previously constructed with the aid of a rigid mold. <h3>Measurements and Main Results</h3> Complications: 8 Introits small wound dehiscences, 3 vaginal shrinking, 1 rectal injury, 1 postoperative bleeding. Biopsies were performed 4 to 6 months after the procedure: sections of mucosa lined with non-keratinized stratified squamous epithelium, with dense fibrous connective tissue permeated by vascular neoformation. The depth and width of each neovagina ranged from 16 to 20 cm (average of 18.49 cm) and width ranges of 5 to 6 cm (average 5.8 cm). All the patients reported, after postoperative evaluation, excellent sensitivity outcomes and good aesthetic results, with the satisfactory appearance of the previously desired female genitalia, a good to an excellent self-lubricated vagina, sufficient for sexual intercourse. Indeed, sensitivity was self-reported as excellent and all of the patients had orgasms either with self-masturbations or penetration on an average of 6.14 weeks after postoperative evaluation, excellent sensitivity outcomes and good aesthetic results, with the satisfactory appearance of the previously desired female genitalia, a good to an excellent self-lubricated vagina, sufficient for sexual intercourse. Indeed, Sensitivity was self-reported as excellent and all of the patients had orgasms either with self-masturbations or penetration on an average of 6.14 weeks after surgery. <h3>Conclusion</h3> LNTFS is a biocompatible material that offers a good vaginal depth and also a moist, smooth, and self-lubricated vaginal canal.

The histological and histochemical features of the esophagus in local breed dogs (Canis familiaris)

A total of eight samples of the esophagus of local breed dogs are used to investigate the histochemical features of the esophagus. The specimens are processed according to paraffin embedding technique protocols and the tissue sections are stained with hematoxylin and eosin, and masons trichrome combined with Alcian blue (pH2.5)-PAS. The esophagus folds the mucosa which is covered by keratinized to non-keratinized stratified squamous epithelium which contains numerous excretory common ducts of esophageal glands. The epithelial thickness of cervical, thoracic and abdominal parts of the esophagus are 221.95±3.41µm, 212.46±5.38 µm, and 173.15±4.09 µm respectively. The lamina propria of the cervical part of the esophagus lacks the muscularis mucosa, while the muscular mucosa in the thoracic part of the smooth muscles appears as scattered interrupted bundles. The esophageal glands are a type of compound tubular mucoserous constructed of the predominated mucous alveoli and little serous acini. When combined with Alcian blue (pH2.5)-PAS stain, the esophageal glands show strong acidic mucopolysaccharides within the mucous alveoli and light blue color within serous acini that denote weak acidic zymogen granules. Tunica muscularis is striated muscle fibers in cervical and thoracic parts and smooth in the abdominal part of the esophagus. The measured thickness of tunica muscularis of cervical, thoracic and abdominal parts are 568.76±6.90 µm, 703.29±7.54µm, and 338.98±7.26 µm respectively.

CLINICAL AND HISTOPATHOLOGICAL FEATURES OF NASOPALATINE DUCT CYST: A 20-YEAR RETROSPECTIVE STUDY

<h3>Objectives</h3> To analyze the clinicopathologic features of nasopalatine duct cysts (NDCs) diagnosed in 2 Brazilian oral and maxillofacial pathology referral centers. <h3>Study Design</h3> A retrospective clinicopathologic study of NDCs diagnosed between 2000 and 2020 was performed. All cases were revised, and clinicopathologic data were collected. <h3>Results</h3> Among 18,121 diagnoses in the oral pathology services, 45 were NDCs (0.2%), with a slightly high prevalence of males (53.3%) and mean age of 43.2 years old. Most lesions were asymptomatic (60%), with a mean size of 2.1 cm. Microscopically, nonkeratinized stratified squamous epithelium was the most common (66.7%). However, epithelial lining varied in 88.9% of cases. There was no significant association between the type of epithelium and cyst size (<i>P</i> = .389). In the histopathological exam, nerves, blood vessels, hemorrhage and chronic inflammatory infiltrate were commonly observed. There was low frequency of mucous glands, sebaceous glands, cholesterol clefts, and multinucleated giant cells. <h3>Conclusions</h3> Our clinical, radiographic, and microscopic findings are similar to those reported in the literature. Due to the morphological diversity of NDC, it is necessary to correlate its histopathologic features with clinical and radiographic findings to establish a correct diagnosis.

MANDIBULAR BUCCAL BIFURCATION CYST: A CASE REPORT

Mandibular buccal bifurcation cyst is an uncommon type of inflammatory cyst arising on the buccal aspect of the roots of a partially or recently erupted first or second mandibular molar, as a result of inflammation in the pericoronal tissues. We present a case of an 8-year-old boy with an asymptomatic buccal swelling of the right mandible close to the partially erupted permanent first molar. Tomographic sections showed a hypodense lesion involving the roots of the first mandibular molar with a buccal expansion of the cortical bone. Enucleation of the lesion was performed without tooth extraction and the correction of bone defect was performed. Histopathological examination showed a cyst lined by a nonkeratinized stratified squamous epithelium with mixed exocytosis and a fibrous wall with a mixed inflammatory infiltrate. The diagnosis of mandibular buccal bifurcation cyst was performed through the association of clinical, tomographic, and histopathologic characteristics.

GLANDULAR ODONTOGENIC CYST IN ANTERIOR MANDIBLE: A CASE REPORT

A 35-year-old male patient was referred to the oral clinic complaining of a sensitivity in the right lower canine, without gingival edema or any other sign. On radiographic examination, a well-defined multilocular, radiolucent lesion associated with the roots of the lower incisor and canine was noted. The initial clinical diagnostic hypotheses were ameloblastoma or keratocyst. After complete removal of the lesion by curettage, microscopic examination revealed a thin and friable cystic capsule and lining composed of nonkeratinized stratified squamous epithelium as well as superficial cuboidal eosinophilic cells and intra-epithelial microcystic structures. The final diagnosis of glandular odontogenic cyst was made. Surgical treatment of the lesion was successful and the patient is being followed up. Since surgical treatment, the patient has been followed up with no evidence of recurrence.

THE ROLE OF ORAL LESIONS IN THE DIAGNOSIS OF BEHÇET'S SYNDROME

Behçet's syndrome is an inflammatory disorder known as a singular model of vasculitis. A 47-year-old male patient was referred to the stomatologist by a rheumatologist after hospitalization for thrombosis of the iliac vein and inferior vena cava and high C-reactive protein and erythrocyte sedimentation rate values. The patient reported recurrent folliculitis and oral and scrotum ulcerations. Intraoral examination revealed ulcerations dispersed through the mucosa. An excisional biopsy was performed in a right buccal mucosa lesion. Histopathologic analysis demonstrated nonkeratinized stratified squamous epithelium with areas of exocytosis and ulceration. Connective tissue presented an intense mixed inflammatory infiltrate, congested vessels, hemorrhage, and vasculitis. HLA-B genotyping identified the presence of HLA-B15. The histopathologic report associated with the other findings enabled the rheumatologist to diagnose the condition. The patient is on daily continuous oral use of colchicine 0.5 mg and prednisolone 20 mg, in addition to weekly subcutaneous administration of 0.1 mL of methotrexate 25 mg/mL and has been without recurrence for 8 months.

Correlation Between Radiographic and Histopathologic Findings Associated with Unerupted Teeth in Dogs.

An association between unerupted teeth and dentigerous cysts is well known,1- 4 however little is known about the presence of disease and histopathologic changes in unerupted teeth without radiographic evidence of cyst formation. Forty-two dogs representing 25 breeds, ranging in age from 5 months to 12 years were selected based on radiographic evidence of an unerupted tooth or teeth, either as a primary complaint or incidental finding. Dogs meeting the study criteria were presented to a private dental referral practice within a period of eighteen months from December 2016 through May 2018. Patients were treated with conservative en bloc resection of the unerupted tooth and overlying bone as well as debridement of any cystic structure and biopsy of the samples collected. Radiographs were evaluated using criteria previously established to assess for evidence of a cyst.1, 5- 7 A total of 68 unerupted teeth were identified; 63 (92.7%) were mandibular first premolar teeth. Of the 63 unerupted mandibular first premolar teeth, 28 (44.4%) had radiographic evidence of a cystic structure. Histopathology revealed that 21 of 28 (75.0%) had evidence of non-keratinizing stratified squamous epithelium consistent with a cyst lining. Of the remaining 35 of 63 (55.6%) mandibular first premolar teeth with no radiographic evidence of a cyst, 27 (77.1%) had no histologic evidence of epithelium associated with the impacted tooth. Notably however, the remaining 8 of 35 (22.9%) unerupted teeth without radiographic evidence of a cyst did have histologic evidence of non-keratinizing stratified squamous epithelium associated with the impacted tooth.

Comparative anatomical, histometrical, and histochemical study of esophagus between ring-necked parakeet (Psittacula krameri) and black-shouldered kite (Elanus caeruleus)

The present study aimed to investigate the esophagus's anatomical, histometrical, histochemical aspects in the Ring-necked parakeet and Black-shouldered Kite. The esophagus in the parakeet was shorter and narrower than the kite esophagus. The crop was a well‐developed sac shape in the parakeet, while the crop was hardly recognizable in the kite. Histological study shows that the esophagus in both species was composed of four layers arranged from inner to outer (mucosa, submucosa, musculosa, finally serosa). These layers showed variances in the height of the fold, the glands number, and the wall layers’ thickness. The mucosa in the esophagus of the kite consisted of non-keratinized stratified squamous epithelium, while in the parakeet, mucosa consisted of keratinized stratified squamous epithelium. The esophageal glands were compound tubuloalveolar in the parakeet, while in the kite, there were simple alveolar glands. The folds in the kite were longest and contained more esophageal glands, while the parakeet glands were more prominent and had fewer numbers within the submucosa. The submucosa layer in the parakeet was thicker than that of the kite. The histochemical results showed a positive reaction of esophageal glands with Alcian blue (PH 2.5), while reacting negatively with Periodic Acid Schiff (PAS) stains due to the acidic mucopolysaccharides secretions nature.

Langerhans Cell Histiocytosis Occurring in the Wall of a Dentigerous Cyst: Presentation of a Case

<h3>Objective</h3> The dentigerous cyst (DC) is the most common developmental odontogenic cyst. It most frequently oc- curs in association with impacted mandibular third molars. The typical radiographic presentation comprises a well-defined unliocluar radiolucency extending from the cemento-enamel junction. Yet, it is well-documented in the literature that a variety of other pathologic entities may demonstrate overlapping clinical and radiographic features. Here we present a case of Langerhans cell histiocytosis (LCH) occurring in the wall of a DC. LCH is charac- terized by infiltrates of CD1a positive cells. Disease may involve a diverse array of tissues and can be solitary or mul- tifocal. LCH occurs across the age range, yet is most commonly diagnosed in the pediatric population. BRAFV600E mutations have been identified in approximately 50% of cases tested. Here we describe the clinical, radiographic, histopathologic, immunohistochemical (IHC) and molecular findings of a case of LCH occurring in the wall of a DC. <h3>Clinical Presentation</h3> An otherwise healthy 12-year-old male presented for evaluation of an impacted right maxil- lary canine. Imaging demonstrated a 2.9 × 2.0 cm wellcircumscribed unliocluar radiolucency associated with tooth #6. <h3>Intervention and Outcome</h3> The impacted canine was extracted and the cyst enucleated under general anesthesia. Microscopic review showed a cystic lining of non-keratinized stratified squamous epithelium with an inflamed fibrovascular connective tissue wall. The inflammatory infiltrate included plasma cells, lymphocytes, numerous eosinophils, and histiocytoid cells. The histiocytoid cells stained positive for S-100 and CD1a IHC confirming the diagnosis of LCH. Analysis for BRAFV600E was negative. The patient was referred to pediatric hematology and oncology for management. <h3>Conclusion</h3> This case of LCH occurring in the wall of a DC highlights the importance of submitting all excised tissue for histopathological review. It also underscores the need for careful attention in examining the microscopic features of inflammatory infiltrates present in the walls of cystic entities.

The urethral plate and the underlying tissue; a histological and histochemical study

To examine the urethral plate and the underlying tissues in children with proximal hypospadias associated with severe chordee. The urethral plate and the underlying tissue specimens were excised to correct severe chordee in 17 children with proximal and perineal hypospadias with severe chordee. The median age was 20 months (range 8-36). Sections samples were marked and examined from proximal to distal. Specimens were examined histologically using hematoxylin-eosin (H/E) and Elastic van Gieson (EvG) stain. Histochemical examination was also performed using smooth muscle actin (SMA) and factor 8 antibodies. For control, samples from four patients with hypoplastic urethra proximal to the meatus including the hypoplastic segments until the normal urethra were taken. In addition, the urethra of an adult patient with penile tumor was used as control. The average size of the 17 tissue samples was 0.5cm×0.5cm x 0.3cm in depth. There was a common pattern that was seen in all the 17 specimens with a variable degree of expression. H/E staining showed that the epithelial lining changed from pseudostratified epithelium at the proximal intact urethra to non-keratinized stratified squamous epithelium at the urethral meatus to keratinized stratified squamous epithelium distally at the urethral plate level. EvG staining showed overall very few elastic fibres that increased slightly in the distal urethral plate. SMA staining showed a circular pattern of smooth muscle cells in the proximal intact urethra that changed to a U-shaped pattern at the level of the meatus, to a triangle shaped pattern just distal to the meatus. The distal urethral plate showed an irregular, disorganized rather flat pattern of the smooth muscles. Factor 8 antibodies staining the blood spaces revealed dysplastic unorganized large blood sinusoids underneath the urethral plate that were different from normal capillaries surrounding the proximal urethra. The urethral plate and the underlying tissues in patients with severe chordee have different structure from normal urethra as compared to available literature and the adult control patient. The lack of elastic fibres may help to explain the rigidity of the ventral penis causing chordee. The disorganized irregular distribution of the smooth muscle fibres is suggestive of the hypoplastic corpus spongiosum. The abnormal large blood sinusoids may explain the poor healing quality of the ventral penis in patients with perineal and proximal patients associated with severe chordee. This may explain persistent/recurrent chordee observed later in those patients with severe chordee when dorsal plication is used. The study also supports the recent trend of 2 stage procedure as a plan of management for patients with proximal and perineal hypospadias with severe chordee and excision of all the dysplastic tissues during the first operation.

Histomorphometrical study of the tongue epithelium of the peregrine falcon (Falco peregrinus).

The aim of this study is to examine the dorsal lingual epithelium of the peregrine falcon (Falco peregrinus) of the family Falconidae. The tongue in its dorsal, lateral and ventral surfaces is covered with a non-keratinized multilayered stratified squamous epithelium. Lamina propria is present beneath the epithelial layers. Morphometrically, thickness of the apex tongue epithelium is more than that in the tongue body. Thickness of the ventral surface of the tongue is less than that in the dorsal one. Thickness of the lateral surface of the tongue was thicker than that in the ventral one and tongue body. Large and small conical papillae appeared on the posterior dorsal surface of the lingual body. There are lingual glands in certain areas of tongue body with numerous openings through the dorsal surface.