[Impact of sinonasal anatomic changes after endoscopic anterior skull base surgery on nasal airflow and air conditioning: a computational fluid dynamics study].

Objective: To analyze the impact of the sinonasal anatomic changes after endonasal endoscopic anterior skull base surgery on the nasal airflow and heating and humidification by computational fluid dynamics (CFD), and to explore the correlation between the postoperative CFD parameters and the subjective symptoms of the patients. Methods: The clinical data in the Rhinology Department of the First Affiliated Hospital of Zhengzhou University from 2016 to 2021 were retrospectively analyzed. The patients received the endoscopic resection of the anterior skull base tumor were selected as the case group, and the adults whose CT scans had no sinonasal abnormalities were chosen as the control group. The CFD simulation was performed on the sinonasal models after reconstructed from the patients' sinus CT images during the post-surgical follow-up. All the patients were asked to complete the Empty Nose Syndrome 6-Item Questionnaire (ENS6Q) to assess the subjective symptoms. The comparison between two independent groups and the correlation analysis were carried out by using the Mann-Whitney U test and the Spearman correlation test in the SPSS 26.0 software. Results: Nineteen patients (including 8 males and 11 females, from 22 to 67 years old) in the case group and 2 patients (a male of 38 years old and a female of 45 years old) in the control group were enrolled in this study. After the anterior skull base surgery, the high-speed airflow moved to the upper part of the nasal cavity, and the lowest temperature shifted upwards on the choana. Comparing with the control group, the ratio of nasal mucosal surface area to nasal ventilation volume in the case group decreased [0.41 (0.40, 0.41) mm-1 vs 0.32 (0.30, 0.38) mm-1; Z=-2.04, P=0.041], the air flow in the upper and middle part of the nasal cavity increased [61.14 (59.78, 62.51)% vs 78.07 (76.22, 94.43)%; Z=-2.28, P=0.023], the nasal resistance decreased [0.024 (0.022, 0.026) Pa·s/ml vs 0.016 (0.009, 0.018) Pa·s/ml; Z=-2.29, P=0.022], the lowest temperature in the middle of the nasal cavity decreased [28.29 (27.23, 29.35)℃ vs 25.06 (24.07, 25.50)℃; Z=-2.28, P=0.023], the nasal heating efficiency decreased [98.74 (97.95, 99.52)% vs 82.16 (80.24, 86.91)%; Z=-2.28, P=0.023], the lowest relative humidity decreased [(79.62 (76.55, 82.69)% vs 73.28 (71.27, 75.05)%; Z=-2.28, P=0.023], and the nasal humidification efficiency decreased [99.50 (97.69, 101.30)% vs 86.09 (79.33, 87.16)%; Z=-2.28, P=0.023]. The ENS6Q total scores of all patients in the case group were less than 11 points. There was a moderate negative correlation between the proportion of the inferior airflow in the post-surgical nasal cavity negatively and the ENS6Q total scores (rs=-0.50, P=0.029). Conclusions: The sinonasal anatomic changes after the endoscopic anterior skull base surgery alter the nasal airflow patterns, reducing the efficiency of nasal heating and humidification. However, the post-surgical occurrence tendency of the empty nose syndrome is weak.

The effect of autosomal dominant polycystic kidney disease on mucociliary clearance.

PURPOSE: Autosomal dominant polycystic kidney disease (ADPKD) is a renal disease with genetic transmisson. Mutations in the PKD1 and PKD2 genes, which encode integral membrane proteins of the cilia of primary renal tubule epithelial cells, are seen in ADPKD. The aim of this study was to evaluate the sinonasal epithelium, which is epithelium with cilia, by measuring the nasal mucociliary clearance time, and to investigate the effect of ADPKD on nasal mucociliary clearance. METHODS: The study included 34 patients, selected from patients followed up in the Nephrology Clinic, and 34 age and gender-matched control group subjects. The nasal mucociliary clearance time (NMCT) was measured with the saccharin test. RESULTS: The mean age of the study subjects was 47.15 ± 14.16 years in the patient group and 47.65 ± 13.85 years in the control group. The eGFR rate was determined as mean 72.06 ± 34.26 mL/min in the patient group and 99.79 ± 17.22 mL/min in the control group (p < 0.001). The NMCT was determined to be statistically significantly longer in the patient group (903.6 ± 487.8 s) than in the control group (580 ± 259 s) (p = 0.006). CONCLUSIONS: The study results showed that the NMCT was statistically significantly longer in patients with ADPKD compared to the control group, but in the linear regression analysis results, no correlation was determined between eGFR and NMCT.

Sinonasal effects of external dacryocystorhinostomy.

OBJECTIVE: External dacryocystorhinostomy is thought to cause mucociliary dysfunction by damaging the mucosa, in turn affecting ciliary activity and mucus quality. This study investigated the effect of external dacryocystorhinostomy on sinonasal function. METHODS: Patients scheduled for unilateral external dacryocystorhinostomy who underwent endoscopic nasal examination and paranasal sinus computed tomography were included in this study. A saccharine test was performed on the planned surgical side and the mucociliary clearance time was determined. The sinonasal quality of life was measured in all patients, pre-operatively and at six months post-operatively, using the Sino-Nasal Outcome Test-22. The Lund-Kennedy endoscopic score was also determined in all patients, both pre- and post-operatively. RESULTS: The study comprised 28 patients (22 females and 6 males). A statistically significant difference was found between the pre- and post-operative saccharine test results (p = 0.006), but not between the pre- and post-operative Sino-Nasal Outcome Test-22 scores (p > 0.05). CONCLUSION: This study is one of only a few to investigate the effect of external dacryocystorhinostomy on sinonasal function. The results showed that external dacryocystorhinostomy impairs mucociliary clearance. The surgical procedure is well tolerated and does not significantly change nasal symptom scores.

Temporal patterns of nasal symptoms in patients with mild severity SARS-CoV-2 infection.

BACKGROUND: No study to date has analyzed the progression of sinonasal symptoms over time in COVID-19 patients. The purpose of this study is to analyze the progression of sinonasal symptoms and risk factors for olfactory dysfunction in the mild severity COVID-19 patient. METHODS: An internet survey was used to assess sinonasal symptoms in patients with COVID-19. Changes in rhinologic domain and symptom-specific Sinonasal Outcome Test (SNOT-22) scores were compared at five time points: two weeks before diagnosis, at diagnosis, two weeks after diagnosis, four weeks after diagnosis, and six months after diagnosis. RESULTS: 521 responses were collected. Rhinologic domain SNOT-22 scores increased significantly (p < 0.001) to 8.94 at the time of diagnosis, remained elevated two weeks post-diagnosis (5.14, p = 0.004), and decreased significantly four weeks post-diagnosis (3.14, p = 0.004). Smell-specific SNOT-22 scores peaked at the time of diagnosis (2.05, p < 0.001), remained elevated two weeks after diagnosis (1.19, p < 0.001), and returned to baseline four weeks post-diagnosis (0.64, p > 0.999). Taste-specific SNOT-22 scores also peaked at diagnosis (2.06, p < 0.001), remained elevated two weeks after diagnosis (1.19, p < 0.001), and returned to baseline four weeks after diagnosis (0.71, p > 0.999). There were no significant differences in sense of smell or taste between 1-month and 6-month timepoints. CONCLUSION: Sinonasal symptoms, particularly loss of smell and taste, may be important presenting symptoms in the mild severity COVID-19 patient. Our findings support incorporating these symptoms into screening protocols. LEVEL OF EVIDENCE: 4.

Spaceflight-Associated Changes in the Opacification of the Paranasal Sinuses and Mastoid Air Cells in Astronauts.

Importance: Head congestion is one of the most common somatic symptoms experienced by astronauts during spaceflight; however, changes in the opacification of the paranasal sinuses or mastoid air cells in astronauts have not been adequately studied. Objectives: To quantify preflight to postflight changes in the opacification of the paranasal sinuses and mastoid air cells in Space Shuttle astronauts and International Space Station (ISS) astronauts and to assess whether there are differences between the 2 groups of astronauts. Design, Setting, and Participants: This cohort study examined preflight and postflight head magnetic resonance images (MRIs) of 35 astronauts who had participated in either a short-duration (≤30 days) Space Shuttle mission or a long-duration (>30 days) ISS mission and had undergone both preflight and postflight MRI. Images were obtained before and after spaceflight. Images were evaluated by 2 neuroradiologists blinded to which mission each astronaut had flown and to which images were preflight or postflight images. Exposure: Spaceflight on the Space Shuttle or the ISS. Main Outcomes and Measures: Measured outcomes included preflight to postflight changes in Lund-Mackay scores for the paranasal sinuses and in scores grading mastoid effusions. Results: Most astronauts in both the Space Shuttle group (n = 17; 15 men; mean [SD] age at launch, 47.7 [3.1] years) and the ISS group (n = 18; 14 men; mean [SD] age at launch, 48.6 [4.7] years) exhibited either no change or a reduction in paranasal sinus opacification as seen on postflight MRI scans (Space Shuttle group: 6 [35.3%] had no sinus opacification before or after spaceflight, 5 [29.4%] had less sinus opacification after spaceflight, 3 [17.6%] had the same amount of sinus opacification before and after spaceflight, and 3 [17.6%] had increased paranasal sinus opacification after spaceflight; ISS group: 8 [44.4%] had no sinus opacification before or after spaceflight, 4 [22.2%] had less sinus opacification after spaceflight, 1 (5.6%) had the same amount of sinus opacification before and after spaceflight, and 5 [27.8%] had scores consistent with increased paranasal sinus opacification after spaceflight). Long-duration spaceflight (ISS group) was associated with an increased risk of mastoid effusion relative to short-duration spaceflight (relative risk, 4.72; 95% CI, 1.2-18.5). Images were obtained a mean (SD) 287.5 (208.6) days (range, 18-627 days) prior to and 6.8 (5.8) days (range, 1-20 days) after spaceflight. Astronauts had undergone either a mean (SD) of 13.6 (1.6) days of spaceflight on the Space Shuttle (17 astronauts) or 164.8 (18.9) days on the ISS (18 astronauts). Conclusions and Relevance: This study found that exposure to spaceflight conditions on the ISS is associated with an increased likelihood for the formation of mastoid effusions. There was no association between exposure to spaceflight conditions and changes in paranasal sinus opacification. The limitations of this study include lack of information concerning medical history and mission-specific operational experience for individual astronauts. Further studies are indicated to determine the cause and composition of the mastoid effusions.

Mucocele de cavidades paranasales / Sinus mucocele

Los mucoceles son quistes expansivos e indolentes de las cavidades paranasales. A pesar de ser lesiones benignas, tienen potencial destructivo local por su expansión crónica y cambios óseos. Su ubicación más frecuente es frontoetmoidal. Se postula que su origen es por alteración de la vía de drenaje de los senos. La clínica es dependiente de su ubicación: los mucoceles frontoetmoidales presentan aumento de volumen, cefalea o proptosis. Las imágenes juegan un rol importante en el diagnóstico, siendo la tomografía computarizada y la resonancia magnética los exámenes que detectan patrones sugerentes de mucoceles. El tratamiento es quirúrgico, donde el abordaje endoscópico ha desplazado al abierto por ser mínimamente invasivo, presentar menos comorbilidades y tener menor tasa de recurrencia.

Mucoceles are expansive and indolent cyst of the paranasal cavities. Despite being benign lesions, they have local destructive potential because of its chronic expansion and bony changes. Its most common location is frontoethmoidal. Alterations in the drainage pathway of sinus is thought to be the origin of mucoceles. The clinical features depend on the location. Frontoethmoidal often presents frontal swelling, headache or proptosis. Imaging plays an important part of diagnosis. Tomography and magnetic resonance have patterns that can suggest the presence of a mucocele. Paranasal sinus mucoceles are primarily treated surgically. The endoscopic surgical management has replaced the open resection because of its minimally invasive treatment, less morbidity and low recurrence rates.

Retronasal olfactory function in patients with smell loss but subjectively normal flavor perception.

OBJECTIVES: The human sense of smell constitutes the main part of flavor perception. Typically, patients with loss of olfactory function complain of diminished perception during eating and drinking. However, some patients with smell loss still report normal enjoyment of foods. The aim of the present study was to compare orthonasal and retronasal olfactory function in patients with non-sinonasal smell loss and subjectively normal flavor perception. METHODS: Nineteen patients (mean age [range] 52.0 [8-83 years]) with self-reported olfactory impairment but subjective normal flavor perception were included. Olfactory performance was assessed using the Sniffin' Sticks (TDI) for orthonasal and the Candy Smell Test (CST) for retronasal function. Visual analogue scales were used for self-assessment of odor (SOP), taste (STP), and flavor perception (SFP), ranging from 0 (no perception) to 10 (excellent perception). RESULTS: Mean (SD) SFP was 8.0 (1.8). Mean (SD) orthonasal TDI-score of all patients was 14.4 (5.3, range 6-25.3) with 11 patients classified as anosmic and eight as hyposmic. Mean/SD retronasal CST-score was 8.8 (2.7, range 3-13) within the range of anosmia/hyposmia. No correlation was found between SFP and the CST (P = .62). CONCLUSION: The present results showed that despite claiming normal flavor perception, our patients were ortho- and retronasally dysosmic using standard tests for olfactory function. Although other explanations could be possible, we suggest that this subjective flavor perception might be due to unconscious memory recall from previously experienced cross-modal sensory interactions. LEVEL OF EVIDENCE: 4 Laryngoscope, 130:1629-1633, 2020.

Peak Sinus Pressures During Sneezing in Healthy Controls and Post-Skull Base Surgery Patients.

OBJECTIVES/HYPOTHESIS: Patients are frequently advised to sneeze with an open mouth and avoid nose-blowing following an endoscopic endonasal approache (EEA) to the skull base, despite a lack of quantitative evidence. This study applies computational fluid dynamics (CFD) to quantify sinus pressures along the skull base during sneezing. STUDY DESIGN: Case-control series. METHODS: Computed tomography or magnetic resonance imaging scans of four post-EEA patients and four healthy controls were collected and analyzed utilizing CFD techniques. A pressure drop of 6,000 Pa was applied to the nasopharynx based on values in the literature to simulate expiratory nasal airflow during sneezing. Peak pressures along the skull base in frontal, ethmoid, and sphenoid sinuses were collected. RESULTS: Significant increases in skull base peak pressure was observed during sneezing, with significant individual variations from 2,185 to 5,685 Pa. Interestingly, healthy controls had significantly higher pressures compared to post-EEA patients (5179.37 ± 198.42 Pa vs. patients 3,347.82 ± 1,472.20 Pa, P < .05), which could be related to higher anterior nasal resistance in unoperated healthy controls (0.44 ± 0.22 vs. 0.31 ± 0.16 Pa/mL/sec for patients, P = .38). The sinus pressure buildup may be due to airway resistance functioning as a valve preventing air from being released quickly. Supporting this theory, there was a strong correlation (r = 0.82) between peak skull base pressure and the ratio of anterior resistance to total resistance. Within-subject variation in pressures between different skull base regions was much lower (average = ~5%). CONCLUSIONS: This study provided the first quantitative analysis of air pressure along the skull base during sneezing in post-EEA patients through CFD, suggesting that pressure buildup may depend on individual anatomy. LEVEL OF EVIDENCE: 3b Laryngoscope, 130:2138-2143, 2020.

Symptom importance, patient expectations, and satisfaction in chronic rhinosinusitis.

BACKGROUND: Sinonasal symptoms and poor quality of life (QOL) prompt chronic rhinosinusitis (CRS) patients to undergo sinus surgery (ESS). However, little is known regarding the symptoms most important to patients and how these impact expectations and postoperative satisfaction. METHODS: A prospective, multi-institutional cohort study of 100 CRS patients undergoing ESS completed a novel adaptation of the 22-item Sino-Nasal Outcome Test (SNOT-22) wherein they rated how important it was for specific symptoms to improve after surgery, along with preoperative expectations and postoperative satisfaction. The primary satisfaction measure was whether a patient would choose to undergo endoscopic sinus surgery (ESS) again. A multivariate, logistic regression model was built using demographics, objective measures, and the adapted SNOT-22 data. Spearman correlation analysis was also performed. RESULTS: Nasal obstruction was rated as "extremely" or "very" important by 93% of patients, followed by smell/taste, thick nasal discharge, need to blow nose, postnasal discharge, and sleep symptoms (range, 61-72%). Symptoms like sadness and embarrassment were not considered important by preoperative patients (≤28%). In multivariate logistic regression, postoperative satisfaction depended on preoperative expectations being met and ESS improving their most important symptoms (odds rato, 19.6-27.5; p < 0.005). Postoperative satisfaction was not correlated with achieving a minimal clinically important difference, but it was correlated with magnitude of change in SNOT-22 (r = 0.35; p < 0.05). CONCLUSIONS: Nasal, smell, and sleep-related symptoms were consdidered most important by this cohort. Meeting of preoperative expectations, improvement of the most important symptoms, and the magnitude of change in the SNOT-22 may drive postoperative satisfaction.

Lund-Mackay Computed Tomography Score Is Associated With Obstructive Pulmonary Function Changes in Chronic Cough Patients.

BACKGROUND: A remarkable relationship between upper airway conditions and lung diseases has been reported. At the same time, sinonasal findings in chronic cough patients have not been fully examined. OBJECTIVE: The purpose of this study is to show paranasal sinus findings and lung function in chronic cough patients without asthma and chest X-ray abnormalities. METHODS: A total of 1412 patients with persistent cough were enrolled in this study. Of these patients, 376 patients were evaluated for further examination, as the patients with asthma and/or chest X-ray abnormality were excluded from the study. Normal control subjects without any chronic respiratory symptoms were also recruited. Pulmonary function was examined by spirometry. A bronchial obstruction reversibility test was applied. The Lund-Mackay computed tomography (CT) score, peripheral blood eosinophil count, and immunoglobulin E concentration in serum samples were examined. The Sino-Nasal Outcome Test was used to determine the severity of clinical symptoms. RESULTS: The patients with an abnormal soft tissue shadow in the paranasal sinus had significant obstructive lung function. The percent predicted forced expiratory volume in 1 second (FEV1.0) and the FEV1.0/forced vital capacity ratio negatively correlated with Lund-Mackay CT scores both before and after bronchodilator inhalation. There was a statistically significant correlation between pulmonary function and eosinophil count. CONCLUSION: The patients with chronic cough frequently had paranasal sinus abnormalities. The Lund-Mackay CT score may be useful for assessing the condition of the lower airway in chronic cough patients. Upper airway examinations should play a part in the management of chronic cough.

Review: The role of computational simulation in understanding the postoperative sinonasal environment.

Nasal surgery improves symptoms in a majority of patients for whom medical treatment has failed. In rhinosinusitis patients, endoscopic sinus surgery aims to alleviate obstruction and re-establish mucociliary clearance. Surgery alters the structure-function relationship within the nasal passage, which is difficult to assess clinically. Computational modelling has been used to investigate this relationship by simulating air flow and environmental variables inside realistic three-dimensional models of the human nasal airway but many questions remain unanswered and need further investigation. The application of computational models to improve pre-surgical planning and post-surgical treatment may not be currently possible due to the absence of knowledge correlating the model-predicted parameters to physiological variables. Links between these parameters to patient outcomes are yet to be established. This article reviews the recent application of computational modelling to understand the nasal structure-function relationship following surgery in patients with sinusitis and nasal obstruction.

Numerical simulation of thermal water delivery in the human nasal cavity.

This work describes an extensive numerical investigation of thermal water delivery for the treatment of inflammatory disorders in the human nasal cavity. The numerical simulation of the multiphase air-droplets flow is based upon the Large Eddy Simulation (LES) technique, with droplets of thermal water described via a Lagrangian approach. Droplet deposition is studied for different sizes of water droplets, corresponding to two different thermal treatments, i.e. aerosol and inhalation. Numerical simulations are conducted on a patient-specific anatomy, employing two different grid sizes, under steady inspiration at two breathing intensities. The results are compared with published in vivo and in vitro data. The effectiveness of the various thermal treatments is then assessed qualitatively and quantitatively, by a detailed analysis of the deposition patterns of the droplets. Discretization effects on the deposition dynamics are addressed. The level of detail of the present work, together with the accuracy afforded by the LES approach, leads to an improved understanding of how the mixture of air-water droplets is distributed within the nose and the paranasal sinuses.

Long-term impact of endoscopic orbital decompression on sinonasal-specific quality of life.

OBJECTIVE: Endoscopic orbital decompression (EOD) is the workhorse surgical intervention for severe thyroid eye disease in Graves disease. Although EOD is a safe and effective procedure, the objective of this study is to determine the impact of orbital decompression on long-term sinonasal-pecific quality of life. METHODS: Retrospective study of 27 patients who underwent EOD by a single surgeon. The primary endpoint was change in preoperative 22-item Sinonasal Outcomes Test (SNOT-22) score at a minimum of 1 year. The secondary endpoint was to determine whether the performance of septoplasty for surgical access in patients without nasal obstruction impacted domain 1 (i.e., rhinologic domain) and total SNOT-22 scores. RESULTS: The mean follow-up was 25.7 ± 11.4 months. Domain 1 scores significantly increased at the first postoperative visit (P ≤ 0.01) and returned to baseline values between 1 and 3 months. At 1 year, significant improvements in both total score and domain 4 and 5 (psychological and sleep dysfunction, respectively) scores were seen (P < 0.01 for all scores). Septoplasty was not associated with a significant change in SNOT-22 score at 1 year (P = 0.48). CONCLUSION: Endoscopic orbital decompression is associated at 1 year with a significant improvement in sinonasal-specific quality of life, which is driven by the psychological and sleep dysfunction domains. Adjunctive septoplasty has no significant impact on SNOT-22 scores. LEVEL OF EVIDENCE: 4. Laryngoscope, 128:785-788, 2018.

Chemosensory function before and after multimodal treatment in chronic rhinosinusitis patients.

OBJECTIVES/HYPOTHESIS: Olfactory dysfunction is common among the general population, with chronic rhinosinusitis (CRS) as one of the leading causes. Patients affected by CRS often report changes in taste sensations; however, quantitative measurements have not been performed to date. Therefore, the present study aimed to investigate gustatory and olfactory function in CRS patients prior to and after multimodal treatment. STUDY DESIGN: Prospective cohort study. METHODS: Twenty-one patients suffering from CRS with nasal polyps (14 male, seven female) with a mean age of 48 ± 15 years were included in the study. Chemosensory function was assessed prior to and approximately 190 days after multimodal treatment, which included endoscopic sinus surgery, oral antibiotics for 5 days, oral steroids for 12 days, and at least 6 weeks of topical nasal steroids. Olfactory function was tested with the Sniffin' Sticks test battery, whereas gustatory function was measured with taste strips. A clinically relevant change in olfactory function was defined as a change of ≥5 points in the threshold, discrimination, and identification scores. RESULTS: Compared to normative data, patients baseline gustatory and olfactory function was impaired. After multimodal treatment, improvements were seen in olfactory function for eight patients (42%), remained stable in 10 patients (53%), and deteriorated in one patient (5%). Taste function remained unchanged following sinus surgery. CONCLUSIONS: Patients suffering from CRS with polyps exhibit olfactory and taste dysfunctions. Multimodal treatment leads to an improvement in olfactory, but not gustatory functionality. LEVEL OF EVIDENCE: 4. Laryngoscope, 128:E86-E90, 2018.

Misdiagnosed paranasal gossypiboma: a 10-year experience with 21 cases at a tertiary center.

BACKGROUND: Different from rhinoliths, the paranasal gossypiboma is a foreign body, such as a surgical sponge, left in the nasal cavity. It is a rare, frequently misdiagnosed disease that has rarely been reported. We summarize its clinical characteristics, management, and possible risk factors. METHODOLOGY: We reviewed medical records of confirmed paranasal gossypibomas at a tertiary medical center between 2005 and 2015. Clinical symptoms, age, sex, anatomic sites, endoscopic photography, computed tomography, intraoperative findings, and past medical history were reviewed. RESULTS: The study included 21 patients, each of whom had ultimately undergone two operations. Among them, 20 underwent endoscopic nasal surgery in primary hospitals, and 15 had been misdiagnosed during the second surgery. The average interval to discovery of a retained foreign body was 200 days. Predominant occurrence sites were the maxillary and ethmoid sinuses. Computed tomography showed paranasal gossypiboma as a heterogeneous cystic lesion with a thin calcified shell. CONCLUSIONS: A history of endoscopic nasal surgery, especially performed at a primary hospital, is a warning sign for clinicians. Computed tomography can add to the warning by showing a heterogeneous cystic lesion with a thin calcified shell. Clinicians should be aware of these characteristics to avoid misdiagnosing paranasal gossypiboma.

Primary Sinonasal Malignant Melanoma: Effect of Clinical and Histopathologic Prognostic Factors on Survival.

BACKGROUND: Mucosal melanoma is a rare malignancy arising from melanocytes of the mucosal surfaces. The pattern and frequency of oncogenic mutations and histopathological biomarkers have a role on distinct tumour behaviour and survival. AIMS: To assess the rate of C-KIT positivity and its effect on survival of surgically treated sinonasal malignant melanoma patients with other histopathological biomarkers and clinical features. STUDY DESIGN: Retrospective cross-sectional study. METHODS: Seventeen sinonasal malignant melanoma patients with a mean age of 65.41 (39-86) years were included. Overall survival and disease-specific survival rates were calculated. The impact of age, gender, stage and extent of the disease, type of surgery, and adjuvant therapies were also taken into consideration. The effect of mitotic index, pigmentation, S100, HMB-45, Melan-A and C-KIT on survival were evaluated. RESULTS: Median tumour size was 20 mm (interquartile range=27.5 mm). Pigmentation was present in 7 (41.2%) cases. Median number of mitoses per millimetre squared was 11 (interquartile range=13). Melan A was positive in 7 (41.2%) patients, ulceration was present in 6 cases (35.3%), and necrosis was present in (47.1%) 8 cases. Six patients (35.3%) were positive for S100, 14 (82.4%) specimens stained positive for HMB-45 and C-KIT (CD117) was positive in 9 cases (52.9%). Three patients (16.7%) developed distant metastasis. Five year overall and disease free survival rates were 61.4% and 43.8%, respectively. CONCLUSION: Although C-KIT positive sinonasal malignant melanoma patients (52.9%) can be candidates for targeted tumour therapies, the studied clinical or histopathological features along with C-KIT seem to have no significant effect on survival in a small group of patients with sinonasal malignant melanoma.