Morphological characterization of the nasopalatine region in human fetuses and its association to pathologies

Case report: Unilateral transnasal endoscopic marsupialization of nasopalatine duct cyst

Nasopalatine duct cyst (NPDC) is the most common type of non-odontogenic cysts of the jaw. It has been treated with complete surgical resection using a sublabial or palatine approach. However, complete removal of the cyst can be accompanied by postoperative complications including oronasal fistula. Recently, endoscopic marsupialization for the disease has been advocated, but there are still few reports regarding the surgery. Herein, we report a case of NPDC that was treated with unilateral transnasal endoscopic marsupialization. A 43-year-old man with no relevant previous medical history was referred to our hospital for the treatment of lesion occupying the right nasal cavity. A computerized tomography scan of the sinus revealed an egg-shaped lesion with a well-defined border centered on the lower half of the nasal cavity and hard palate. Based on the site of the lesion, it was considered to be NPDC. Transnasal endoscopic marsupialization was performed to diagnose and improve nasal obstruction. Histopathological examination revealed stratified squamous epithelium without atypia, which was consistent with NPDC. Although the patient noticed paresthesia of the right upper incisor area, symptoms improved 3 months after surgery. Written informed consent was obtained from the patient for the publication of any potentially identifiable images or data included in this article. Transnasal endoscopic marsupialization for NPDC is minimally invasive and useful; however, it is necessary to build evidence for an appropriate excision range based on the position and size of the lesion.

Unique air inclusions within the nasopalatine duct indicating its presence radiographically: a case presentation

The anterior maxilla is characterized by the nasopalatine canal that originates bilaterally from the anterior nasal floor, subsequently fuses, and terminates at the incisive foramen in the anterior palate. Embryologically, this structure forms within the primary palate, and contains the neurovascular bundle, but also continuous epithelialized bands. The latter, termed nasopalatine ducts, usually degenerate and/or obliterate before birth. However, in some individuals, the ducts may remain partially or completely patent. The present case report describes for the first time in the literature a rare finding of air inclusions within the anatomical area of the nasopalatine canal indicating the presence of a nasopalatine duct as visualized with cone beam computed tomography. The patient was asymptomatic and the radiographic findings were seen incidentally. An endoscopic inspection of the anterior nasal cavities confirmed the presence of the nasal openings of the partially patent nasopalatine ducts.

Immunolocalization of VEGF/VEGFR system in human fetal vomeronasal organ during early development

The vomeronasal system (VNS) is an accessory olfactory structure present in most mammals adhibited to the detection of specific chemosignals implied in social and reproductive behavior. The VNS comprises the vomeronasal organ (VNO), vomeronasal nerve and accessory olfactory bulb. VNO is characterized by a neuroepithelium constituted by bipolar neurons and supporting and stem/progenitor cells. In humans, VNO is present during fetal life and is supposed to possess chemoreceptor activity and participate in gonadotropin-releasing hormone neuronal precursor migration toward the hypothalamus. Instead, the existence and functions of VNO in postnatal life is debated. Vascular endothelial growth factor (VEGF) and its receptors (VEGFRs) have been demonstrated to play fundamental roles in various neurogenic events. However, there are no data regarding the localization and possible function of VEGF/VEGFRs in human fetal VNO. Therefore, this study was conceived to investigate the expression of VEGF/VEGFRs in human VNO in an early developmental period (9-12 weeks of gestation), when this organ appears well structured. Coronal sections of maxillofacial specimens were subjected to peroxidase-based immunohistochemistry for VEGF, VEGFR-1 and VEGFR-2. Double immunofluorescence for VEGF, VEGFR-1 or VEGFR-2 and the neuronal marker protein gene product 9.5 (PGP 9.5) was also performed. VEGF expression was evident in the entire VNO epithelium, with particularly strong reactivity in the middle layer. Strongly VEGF-immunostained cells with aspect similar to bipolar neurons and/or their presumable precursors were detected in the middle and basal layers. Cells detaching from the basal epithelial layer and detached cell groups in the surrounding lamina propria showed moderate/strong VEGF expression. The strongest VEGFR-1 and VEGFR-2 expression was detected in the apical epithelial layer. Cells with aspect similar to bipolar neurons and/or their presumable precursors located in the middle and basal layers and the detaching/detached cells displayed a VEGFR-1 and VEGFR-2 reactivity similar to that of VEGF. The basal epithelial layer exhibited stronger staining for VEGFRs than for VEGF. Cells with morphology and VEGF/VEGFR expression similar to those of the detaching/detached cells were also detected in the middle and basal VNO epithelial layers. Double immunofluorescence using anti-PGP 9.5 antibodies demonstrated that most of the VEGF/VEGFR-immunoreactive cells were neuronal cells. Collectively, our findings suggest that during early fetal development the VEGF/VEGFR system might be involved in the presumptive VNO chemoreceptor activity and neuronal precursor migration.

Cysts and Pseudocysts of the Oral Cavity: Revision of the Literature and a New Proposed Classification

This article includes a comprehensive and up-to-date review on the cysts of the oral cavity. Several classifications of odontogenic (OC) and non-odontogenic (non-OC) oral cysts and the surrounding regions have been proposed. We suggest a new critical classification based on an established relationship between anatomical area, histological origin and clinical behavior (frequency, rate of recurrence, malignant potential). Moreover, the differential cytokeratin (CKs) expression of the various cysts is reported as epithelium-specific markers of differential diagnosis. Finally, issues related to differential diagnosis and therapeutic approaches of the cysts included in the two groups are described.

The Incisive Canal: A Comprehensive Review

The incisive canal, also known as the nasopalatine canal, is an interosseous conduit through the anterior maxilla connecting the oral and nasal cavities. Within this canal lies the nasopalatine nerve and the vascular anastomosis between the greater palatine and sphenopalatine arteries. The embryology of the canal has led to interesting theories explaining its function. Efforts have been made to describe the morphometrics of the incisive canal by radiologic evaluation across sex and ethnicities. This paper aims to review the current literature on the embryology, anatomy, and clinical relevance of the incisive canal.

Fetal Development of Human Oral Epithelial Pearls with Special Reference to Their Stage-Dependent Changes in Distribution

Objective

To access detailed distribution and age-dependent changes of oral epithelial pearls.

Design

Investigation and analysis with human fetal serial sections.

Setting

Institute of Embryology.

Methods

This study examined serial frontal sections of the upper and lower jaws of 19 human fetuses at 12 to 18 weeks and of the lower jaws of four late-stage fetuses.

Results

The upper jaw contained more than 20 midline and more than 60 lateral pearls greater than 20 μm in diameter, whereas the lower jaw contained fewer than 30 pearls of the same size. Midline pearls in the upper jaw were often cylindrical or rugby-ball shaped, whereas all pearls in the lower jaw were small and spherical. Epithelial pearls in the upper jaw started developing along the upper midline until 12 weeks; lateral pearls and additional midline pearls (or strictly, paramedian pearls) developed until 15 weeks. In the lower jaw, however, pearl development started at 18 weeks and was almost always from the dental lamina. Some of the fetuses assessed had an open nasopalatine canal without a duct, but there was no fibrous connection between this canal and pearls. Similarly, the lip frenulum or incisive suture was not connected with these pearls.

Conclusion

The timing and sequence of development suggest that postfusion rupture of the palate by midline pearls was unlikely.

Nasopalatine Island Advancement Flap

BACKGROUND

Anterior maxilla is a high esthetic region of the mouth. Some flaps are introduced for bone graft coverage, mainly based on secondary epithelization of connective tissue-periosteal tissues. This article evaluates the versatility of a new mucoperiosteal flap for reproducible coverage in anterior maxilla.

METHODS

In 5 mongrel dogs a 5 mm width mucosal defect in labial mucosa was created after extraction of upper jaw incisors. Nasopalatine island advancement flap was used for mucosal replacement.

RESULTS

Flap survival and healing was uneventful without necrosis.

CONCLUSION

Nasopalatine island advancement flap is a reliable axial island flap for anterior maxillary reconstruction.

Bilateral endoscopic endonasal marsupialization of nasopalatine duct cyst

Nasopalatine duct cysts are the most common non-odontogenic cysts in the maxilla, and are conventionally treated through a sublabial or palatine approach. Recently, the endoscopic approach has been used, but experience is extremely limited. We treated a 29-year-old male with nasopalatine duct cyst by endoscopic marsupialization, but paresthesia of the incisor region occurred after surgery. This paresthesia gradually remitted within 6 months. The nasopalatine nerve, which innervates the upper incisor region, enters two lateral canals separately at the nasal floor and exits the central main canal at the palate. Damage to the bilateral nasopalatine nerves might lead to paresthesia, so we recommend careful examination for nerve fibers during endoscopic surgery, especially if fenestration is performed on both sides.

Cone-beam computed tomographic analysis of the morphological characterization of the nasopalatine canal in a pediatric population

PURPOSE

Knowledge of the nasopalatine canal (NPC) is necessary for understanding the morphology and pathogenesis of lesions that occur in this region. The purpose of the present study was to analyze the dimensions and anatomic characteristics of the NPC in a pediatric population using cone-beam computed tomography (CBCT).

STUDY DESIGN

Reformatted sagittal, coronal, and axial slices of 368 individual CBCT images were analyzed with regard to dimensions and anatomic features of the NPC.

RESULTS

Funnel shape of the NPC was most commonly found [26.9 % (99)], followed by banana shape [19.6 % (72)]. There was no statistically significant difference (p = 0.317) between girls and boys in terms of NPC shape. The mean width of incisive foramen was found to be 2.53 mm with a significant difference (0.002). The mean NPC length was found to be 10.83 mm and the mean canal length was found to be significantly longer in boys than girls (p < 0.000).

CONCLUSION

The present study provides new information on the literature concerning the identification of the anatomical structure of NPC. This finding may assist clinicians in understanding the morphology and preventing possible complications in this region.