Characteristics and risk factors of mucosal cysts in the paranasal sinuses

Evaluation of Anatomical Variations of the Maxillary Sinus in Patients With and Without Mucous Retention Cyst

Objectives: Mucous retention cyst (MRC) is a benign and self-limited lesion that can be caused by many risk factors, including anatomical variations of the sinonasal region. This study aims to investigate the relationship between anatomical variations and the presence of MRC. Materials and Methods: In total, 2109 sinonasal cone beam computed tomography images were evaluated for the presence of MRC, and the sinonasal anatomical regions such as the osteomeatal complex (OMC), infundibulum length, ostium height, the diameter of the ostium, the presence of accessory ostium, concha bullosa, and mucosal thickening of the maxillary sinuses. Shapiro-Wilk normality test, independent sample t-test, and chi-square test were used for statistical analysis, and P < .05 was considered significant. Results: The prevalence of MRC was 119 (5.6%) cases. The average diameter of the ostium in cases with and without MRC was 0.49 ± 0.41 mm and 0.99 ± 0.76 mm, respectively, which showed a significant inverse relationship(P < .001). A significant relationship was found between the septum deviation, the ostium height, the concha bullosa, and the accessory ostium with the presence of MRC (P < .001). Conclusions: Sinonasal anatomical variations such as ostium diameter, ostium height, septal deviation, the presence of accessory ostium, and concha bullosa can cause MRC development, and considering that surgery may be necessary in some cases; this could be of great importance to clinicians and surgeons for treatment and prevention of development or recurrence of these pseudocysts in patients.

Volumetric analysis of mucous retention cysts in the maxillary sinus: A retrospective study using cone-beam computed tomography

Purpose

The aim of this study was to evaluate the volumetric characteristics of mucous retention cysts (MRCs) in the maxillary sinus and to analyze potential associations of MRCs with dentoalveolar pathologies.

Materials and Methods

Cone-beam computed tomography (CBCT) scans exhibiting bilateral maxillary sinuses that were acquired from January 2016 to February 2019 were initially screened. A total of 227 scans (454 sinuses) that fulfilled the inclusion criteria were included. The presence, location, and volumetric characteristics of the diagnosed MRCs were evaluated on CBCT images using the 3D-Slicer software platform. The presence of MRCs was correlated with potential influencing factors including age, sex, and dentoalveolar pathology. For MRCs located on the sinus floor, factors with a potential impact on the volume, surface, and diameter were analyzed.

Results

An MRC was present in 130 (28.6%) of the 454 sinuses. Most MRCs were located on the sinus walls and floor. The mean MRC volume, surface, and diameter were 551.21±1368.04 mm³, 228.09±437.56 mm², and 9.63±5.40 mm, respectively. Significantly more sinuses with associated endodontically treated teeth/periapical lesions were diagnosed with an MRC located on the sinus floor. For MRCs located on the sinus floor, endodontic status exhibited a significant association with increased volume, surface, and diameter.

Conclusion

Periapical lesions might be a contributing factor associated with the presence and volume of MRCs located on the sinus floor. The 3D-Slicer software platform was found to be a useful tool for clinicians to analyze the size of MRCs before surgical interventions such as sinus floor elevation procedures.

French Otorhinolaryngology Society (SFORL) good practice guidelines for dental implant surgery close to the maxillary sinus

OBJECTIVES

To draw up guidelines for ENT management associated with dental implant surgery with or without sinus lift.

MATERIALS AND METHODS

The methodology followed the rules of laid down by the French Health Authority (HAS): "Methodological bases for drawing up professional recommendations by formalized consensus". The chosen method was the RAND/UCLA "RAND appropriateness method" (short version).

RESULTS

In the pre-implantation check-up, it is recommended to systematically screen for sinonasal pathology on medical interview and to favor 3D CT or cone-beam imaging. It is recommended that imaging include the entire maxillary sinus when the patient does not have sinonasal history or functional signs on interview. Otherwise, examination of all sinonasal cavities is recommended. This attitude enables simultaneous analysis of maxillary infrastructure for pre-implantation work-up and assessment of sinonasal cavity status. Sinus mucosal incidentalomas are very common in the healthy population and must be assessed with reference to the clinical, endoscopic and radiological context.

CONCLUSION

This formalized expert consensus establishes a common base of knowledge, to clarify the issues and clinical situations and to standardize practices.

The value of the apparent diffusion coefficient calculated from diffusion-weighted magnetic resonance imaging scans in the differentiation of maxillary sinus inflammatory diseases

OBJECTIVES

This study examined the value of the apparent diffusion coefficient (ADC) calculated by using diffusion-weighted imaging (DWI) in the differentiation of inflammatory lesions of the maxillary sinus.

STUDY DESIGN

Sixty-five maxillary sinus magnetic resonance imaging (MRI) scans with findings suggestive of inflammatory lesions were qualitatively categorized into 4 distinct groups by using T2-weighted images: group 1: presence of mucosal thickening; group 2: presence of sinonasal polyps or mucous retention cysts; group 3: presence of fluid identified by air-fluid levels with a homogeneous signal intensity; and group 4: presence of fluid identified by air-fluid levels with a heterogeneous signal intensity. The ADC of each imaging finding was measured by using a 5-mm area of interest. Statistical differences between the groups were determined by using nonparametric tests with a 5% significance level.

RESULTS

Statistically significant differences were observed between group 1 and the other groups. Mucosal thickening was associated with lower ADC values compared with the other inflammatory lesions.

CONCLUSIONS

The ADC can be useful in differentiating mucosal thickening from other inflammatory alterations in the maxillary sinuses. Mucosal thickening had more restricted water diffusion compared with the other inflammatory lesions.

Incidental findings in MRI of the paranasal sinuses in adults: a population-based study (HUNT MRI)

BACKGROUND

Diagnostic imaging of the head is used with increasing frequency, and often includes the paranasal sinuses, where incidental opacifications are found. To determine the clinical relevance of such findings can be challenging, and for the patient such incidental findings can give rise to concern if they are over-reported. Studies of incidental findings in the paranasal sinuses have been conducted mostly in patients referred for diagnostic imaging, hence the prevalence in the general population is not known. The purpose of this study was to determine the prevalence and size of incidental opacification in the paranasal sinuses in a non-selected adult population using magnetic resonance imaging (MRI) without medical indication, and to relate the results to sex and season.

METHODS

Randomly and independent of medical history, 982 participants (518 women) with a mean age of 58.5 years (range, 50-66) underwent MRI of the head as part of a large public health survey in Norway. The MRIs included 3D T1 weighted volume data and 2D axial T2 weighted image (WI). Opacifications, indicating mucosal thickenings, polyps, retention cysts, or fluid, were recorded if measuring more than 1 mm.

RESULTS

Opacifications were found in 66% of the participants. Mucosal thickenings were found in 49%, commonly in the maxillary sinuses (29%) where 25% had opacifications that were less than 4 mm in size. Other opacifications occurred in the anterior ethmoid (23%), posterior ethmoid (21%), frontal sinus (9%), and sphenoid (8%). Polyps and retention cysts were also found mainly in the maxillary sinuses in 32%. Fluid was observed in 6% of the MRIs. Mucosal thickening was observed more frequently in men than in women (P <0.05). No seasonal variation was found.

CONCLUSIONS

In this large non-selected sample, incidental opacification in the paranasal sinuses was seen in two out of three participants, and mucosal thickening was seen in one out of two. Fluid was rare. Knowledge of incidental opacification is important because it can affect clinical practice.

Pathological changes in the maxillary sinus mucosae of patients with recurrent odontogenic maxillary sinusitis

Objective: To study the structural and functional changes of maxillary sinus mucosae of patients with odontogenic maxillary sinusitis, and to improve the therapeutic effects.

Methods: Ten mucosal biopsy samples collected during the surgeries of patients with recurrent odontogenic maxillary sinusitis were selected as Group A. Another ten mucosal biopsy sample were collected during retention cyst-removing surgeries and referred to as Group B. The mucosae were put in 10% neutral formalin solution for 1 day and prepared into 5-7 µm thick paraffin sections which were subjected to hematoxylin-eosin staining. The reactions included: (1) Reaction with T-lymphocyte (CD-3); (2) reaction with T-helper cell (CD-4); (3) reaction with T-suppressing cell (CD-8); (4) reaction with B-lymphocyte (CD-20). Polymeric horseradish peroxidase visualized detection system was used. The contents of CD3, CD4, CD8 and CD20 in the stained cells of the maxillary sinus mucosal layer were calculated. The responses of receptors to muramidase were classified as mild, moderate and strong. All data were analyzed by Statistica 6.0 package for Windows based on Mann-Whitney non-parametric standards.

Results: The epithelial tissues in the maxillary sinus mucosa of Group B were covered with multiple rows of cilia. The epithelial cells of Group A suffered from degeneration, shrinkage and desquamation. Different cells were distributed in the autologous mucosal layer, of which macrophages, fibroblasts, lymphocytes and neutrophils were dominant. The average contents of macrophages and lymphocytes accounted for 42.8%. Lymphocyte subset analysis showed that the number of CD3 cells exceeded that of CD20 ones and there were more CD4+ cells than CD8+ ones. T-helper and T-suppressing cells were distributed remarkably differently. CD8+ cells were mainly located inside and under the epithelium, while CD4+ cells were scattered in the autologous matrix.

Conclusion: For patients with recurrent odontogenic maxillary sinusitis, the maxillary sinus mucosa mainly suffered from regeneration of epithelial tissues and inhibition of cell proliferation, which were accompanied by damages to the protective and shielding effects of the mucociliary transport system. Macrophages and lymphocytes dominated in the infiltration of autologous mucosal layer, and the coexisting copious fibroblasts indicated the onset of inflammation.

Maxillary sinus retention cysts protruding into the inferior meatus

Although most of the maxillary sinus retention cysts are asymptomatic, a few of them increase in size and cause symptoms. However, they rarely erode bony walls nor protrude into the inferior meatus. I present 2 cases with maxillary sinus retention cysts protruding into the inferior meatus by making a large defect on the medial wall of the maxillary sinus.

Cysts of the maxillary sinus: a literature review

BACKGROUND

Patients with isolated mucosal cysts of the maxillary sinus (MMC) often undergo surgical treatment despite the absence of relevant symptoms. Some physicians believe that MMC might increase in size and cause complications in the future. The anticipated value of this study is to consolidate and improve the understanding of MMC based on published data and to contribute to avoiding unnecessary interventions.

METHODS

We performed a comprehensive review of the literature regarding definition, etiology, epidemiology, natural course, and best treatment of MMC.

RESULTS

Among the 988 papers found in the literature search, 33 studies were selected to be relevant. Among those studies, there are only a few prospective controlled studies. Their prevalence rates range broadly from 3.6% to 35.6% according to different diagnostic methods as well as different indications for imaging. Recent prospective studies showed no correlation of MMC with sinonasal complaints or Lund-Mackay computed tomography (CT) score. The natural course is characterized by a decrease in size of MMC in 30% of the cases, an unchanged status in 50% to 60%, and an increase in 8% to 20% of the cases.

CONCLUSION

MMC are harmless, mostly asymptomatic lesions that usually do not need surgical treatment. If surgery is indicated, endonasal endoscopic techniques should be the gold-standard approach.

Mucosal maxillary cysts: long-term subjective outcomes after surgical treatment

Mucosal maxillary cysts (MMCs) are usually asymptomatic and are often diagnosed as an incidental finding. The aim of this study is to assess clinical significance of MMCs and the long-term effect of surgical treatment on the symptoms initially addressed to MMCs. The study included a retrospective analysis of 64 patients who had undergone surgery for MMC using a questionnaire focused mainly on the effect surgery had on symptoms. Mean time of follow-up was 79 months. Patients were also divided and compared according to the presence of rhinitic symptoms. Twenty-six patients (63.4%) reported complete disappearance of symptoms, 8 (19.5%) reported improvement, 4 (9.7%) reported no change in symptoms following surgery and 3 (7.3%) reported that symptoms reappeared. Significantly (p = 0.0365) better results were achieved in patients without preexisting rhinitic symptoms. This study supports the opinion that in some cases, MMCs are involved in the development of sinonasal symptoms. Surgical treatment leads, in most patients, to disappearance or improvement of symptoms and the effect is better in patients without rhinitic symptoms.