Deep learning model for differentiating nasal cavity masses based on nasal endoscopy images.

BACKGROUND: Nasal polyps and inverted papillomas often look similar. Clinically, it is difficult to distinguish the masses by endoscopic examination. Therefore, in this study, we aimed to develop a deep learning algorithm for computer-aided diagnosis of nasal endoscopic images, which may provide a more accurate clinical diagnosis before pathologic confirmation of the nasal masses. METHODS: By performing deep learning of nasal endoscope images, we evaluated our computer-aided diagnosis system's assessment ability for nasal polyps and inverted papilloma and the feasibility of their clinical application. We used curriculum learning pre-trained with patches of nasal endoscopic images and full-sized images. The proposed model's performance for classifying nasal polyps, inverted papilloma, and normal tissue was analyzed using five-fold cross-validation. RESULTS: The normal scores for our best-performing network were 0.9520 for recall, 0.7900 for precision, 0.8648 for F1-score, 0.97 for the area under the curve, and 0.8273 for accuracy. For nasal polyps, the best performance was 0.8162, 0.8496, 0.8409, 0.89, and 0.8273, respectively, for recall, precision, F1-score, area under the curve, and accuracy. Finally, for inverted papilloma, the best performance was obtained for recall, precision, F1-score, area under the curve, and accuracy values of 0.5172, 0.8125, 0.6122, 0.83, and 0.8273, respectively. CONCLUSION: Although there were some misclassifications, the results of gradient-weighted class activation mapping were generally consistent with the areas under the curve determined by otolaryngologists. These results suggest that the convolutional neural network is highly reliable in resolving lesion locations in nasal endoscopic images.

Diagnostic accuracy of clinical visual assessment using endoscopic images for nasal cavity mass lesions.

Objectives: Discrimination of nasal cavity lesions using nasal endoscopy is challenging because of the differences in clinical manifestations and treatment strategies. We aimed to investigate the diagnostic accuracy of clinical visual assessment (CVA) of nasal cavity masses using endoscopic images and determine whether there is a difference according to pathologic class and the examiners' experience. Methods: We collected pathologically confirmed endoscopic images of normal findings, nasal polyp (NP), benign tumor, and malignant tumor (each class contained 100 images) randomly selected. Eighteen otolaryngologists, including six junior residents, six senior residents, and six board-certified rhinologists classified the test set images into four classes of lesions by CVA. Diagnostic performance according to the pathologic class and the examiner's experience level was evaluated based on overall accuracy, F1-score, confusion matrix, and area under the receiver operating characteristic curve (AUC). Results: Diagnostic performance was significantly different according to the pathological class of nasal cavity mass lesions with the overall accuracy reported high in the order of normal, NP, benign tumor, and malignant tumor (0.926 ± 0.100; 0.819 ± 0.135; 0.580 ± 0.112; 0.478 ± 0.187, respectively), F1 score (0.937 ± 0.076; 0.730 ± 0.093; 0.549 ± 0.080; 0.554 ± 0.146, respectively) and AUC value (0.96 ± 0.06; 0.84 ± 0.07; 0.70 ± 0.05; 0.71 ± 0.08, respectively). The expert rhinologist group achieved higher overall accuracy than the resident group (0.756 ± 0.157 vs. 0.680 ± 0.239, p < .05). Conclusion: CVA for nasal cavity mass was highly dependent on the pathologic class and examiner's experience. The overall accuracy was reliably high for normal findings, but low in classifying benign and malignant tumors. Differential diagnosis of lesions solely based on nasal endoscopic evaluation is challenging. Therefore, clinicians should consider further clinical evaluation for suspicious cases.

Intravascular papillary endothelial hyperplasia of the maxillary sinus extending into the contralateral nasal cavity.

INTRODUCTION: Intravascular papillary endothelial hyperplasia (IPEH) predominantly occurs in the subcutaneous and dermal regions and rarely originates from the sinonasal mucosa. CASE PRESENTATION: We report on the case of a 58-year-old male patient who presented with progressive bilateral nasal obstruction, left-sided epiphora, and intermittent epistaxis. Computed tomography revealed a soft tissue opacity in the left maxillary sinus with intersinusoidal nasal wall demineralization, extending into the surrounding ethmoid cells and the right nasal cavity through a contralateral deviation of the nasal septum. Contrast-enhanced T1-weighted magnetic resonance imaging further confirmed these findings. The IPEH originating from the maxillary sinus extended into the contralateral nasal cavity, and it was successfully removed using an endoscopic endonasal approach, avoiding overly aggressive treatment. CONCLUSION: This case report highlights the diagnostic challenges of IPEH in the sinonasal region and the importance of considering IPEH as a differential diagnosis in patients presenting with nasal obstruction, epiphora, and intermittent epistaxis.

The impact of multidisciplinary approaches on the outcomes of olfactory neuroblastoma treated with postoperative radiotherapy.

BACKGROUND: We investigated the outcomes of postoperative radiation therapy for olfactory neuroblastoma (ONB) and our cross-departmental collaboration to enhance the effectiveness of cancer treatment. METHODS: We retrospectively evaluated 22 patients with ONB who underwent postoperative radiotherapy after tumor resection. En bloc resection was performed; pathology specimens were prepared in coronal sections; and irradiation fields were determined after discussion with radiation oncologists, head and neck surgeons, and pathologists. RESULTS: The overall survival and local control rates were 95.5% and 100%, respectively, at a median 37-month follow-up. The 3- and 5-year disease-free survival (DFS) rates were 64.4% and 56.3%, respectively. Of the 22 patients, 9 (8 Kadish C and 1 Kadish B) had disease recurrence. Of the nine patients, five had positive margins and two had closed margins; cervical lymph node recurrence occurred in six, and distant metastasis with or without cervical lymph node recurrence occurred in three. DFS analysis of risk factors showed no statistically significant differences, but positive margins were a significant recurrence factor in multivariate analysis. CONCLUSIONS: The local control rate of ONB treated with postoperative radiation therapy was 100%. This may be attributed to cross-departmental cooperation between head and neck surgeons, pathologists, and radiation oncologists, which resulted in accurate matching of CT images for treatment planning with the location of the tumor and positive margins. Longer follow-up periods are required to evaluate the effectiveness of our strategy.

Treatment of unilateral olfactory neuroblastoma: Appropriate extent of surgical resection and potential for olfactory preservation.

Historically, comprehensive surgical resection for olfactory neuroblastoma has included the bilateral olfactory epithelium, cribriform plate, overlying dura, olfactory bulbs and tracts. This results in postoperative anosmia that may significantly impact a patient's quality of life without definitive added benefit in survival. The prevalence of occult intracranial disease is low, especially for Hyams grade I and II tumors. A unilateral approach sparing the contralateral cribriform plate and olfactory system can be considered for select cases of early stage, low-grade tumors when the disease does not cross midline to involve the contralateral olfactory cleft or septal mucosa and when midline dural margins can be cleared with frozen pathology. Approximately half of patients who undergo unilateral resection may have residual olfaction even with adjuvant unilateral radiation. Early data suggest favorable disease-free survival and overall survival for patients who underwent the unilateral approach; however, larger sample studies are needed to confirm comparability to bilateral resections regarding oncologic outcomes.

Squamous cell carcinoma of the nasal vestibule in the Netherlands: A clinical and epidemiological review of 763 cases (2008-2021).

BACKGROUND: Squamous cell carcinoma of the nasal vestibule (SCCNV) is a rare disease, distinctly different in presentation, treatment, and outcome from squamous cell carcinoma (SCC) of the nasal cavity and paranasal sinuses. However, these are often not analyzed separately. METHODS: The Netherlands Cancer Registry (NCR) and pathology reports from the Dutch Nationwide Pathology Databank (PALGA) were used to identify all newly diagnosed SCCNV cases in the Netherlands between 2008 and 2021. RESULTS: A total of 763 patients were included. The yearly incidence rate displayed a significant downward trend with an annual percentage change (APC) of -3.9%. The 5-year overall survival (OS) and disease-free survival were 69.0% and 77.2%, respectively. The 5-year relative survival was 77.9% and improved slightly over the inclusion period. OS for patients who were staged cT3 appeared to be worse than those staged cT4a, calling the applicability of the TNM-classification into question. CONCLUSION: SCC of the nasal vestibule is rare, with declining incidence rates. Introducing a specific topography code for SCCNV is recommended to enhance registration accuracy. The TNM classification seems poorly applicable to SCCNV, suggesting the need to explore alternative staging methods.

Pathogenic Somatic Mutation of DICER1 and Clinicopathological Features in Nasal Chondromesenchymal Hamartomas: A Series of Nine Cases.

Nasal chondromesenchymal hamartoma (NCMH) is a rare benign polypoid mesenchymal tumor arising in the nasal cavity and/or paranasal sinuses. Recognizing these sporadic, rare lesions is crucial, as surgical complete removal of the mass is the common treatment approach. This retrospective study analyzed the demographics, symptoms, and imaging data of 9 patients diagnosed with NCMH between January 2017 and June 2023, possibly representing the largest single-center adult case cohort to date. Diagnostic techniques included nasal endoscopy, CT/MRI scan, immunohistological studies, and morphologic comparisons. Pathologic specimens were subjected to Sanger sequencing of exons 24 and 25 of DICER1. The average age of 9 cases was 24.4 years, and the oldest was 55 years. Four of the patients were children, ranging from 1 year old to 11 years old, with an average of 4.5 years. Nasal congestion is the most common registered symptom. Endoscopic findings showed that most patients had smooth pink neoplasms or polypoid masses in the nasal meatus. Radiologic scanning revealed soft-tissue density masses that occupied the nasal cavity. Histologically, the characteristic structure of NCMHs is immature cellular cartilage nodules and mature cartilage nodules distributed in a loose mucoid matrix. Five of the 9 patients had somatic DICER1 missense mutations. Four of the patients with DICER1-mutated NCMH exhibited a p.E1813 missense hotspot mutation. We also report a case of a rare p.P1836H missense mutation. The detected DICER1 somatic mutations provide compelling evidence of an association with the DICER1 tumor family. We emphasize the importance of pathologic consultation and the need for pathologists to accumulate experience in NCMH diagnosis to avoid misdiagnosis.

Diagnostic benefits of platelet-to-lymphocyte, neutrophil-to-lymphocyte, and albumin-to-globulin ratios in dogs with nasal cavity diseases.

BACKGROUND: A multimodal approach for diagnostic tests under anesthesia is required to diagnose nasal cavity pathology (NP) reliably in dogs. Blood test results may provide clues to the suspected NP. METHODS: This prospective blinded study assessed 72 dogs with chronic nasal discharge due to NPs, and 10 healthy dogs as the control group (CG). NPs were diagnosed using whole-body computed tomography (CT), upper airway endoscopy, examination of nasal mucosal swabs by bacterial and fungal culture, and histopathological examination of nasal mucosa biopsies. The exclusion criteria were the presence of any additional diseases or corticosteroid pre-treatment. In consideration of these exclusion criteria, 55 dogs entered the study. Dogs were classified into benign (benign tumors, idiopathic rhinitis (IR), and others) and malignant (carcinomas and sarcomas) NP groups. Blood count and blood chemistry tests were performed. The neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and albumin-to-globulin ratio (AGR) were calculated and compared. RESULTS: 25 dogs with malignant NP (13 and 12 with carcinomas and sarcomas, respectively) and 30 dogs with benign NP (seven with benign tumors,13 with IR, and 10 others) were included. In general, in dogs with NP there were only slight abnormalities in complete blood count. However, PLR was significantly higher in dogs with malignant NP (carcinoma and sarcoma) than in those with benign NP and in the CG. Compared with the CG, the NLR was significantly increased in all dogs with NP, and the AGR was mild but significantly lower, except in dogs with sarcomas and benign tumors. CONCLUSIONS: In dogs with nasal disease alone, there are usually no marked abnormalities in blood count. However, while mildly increased NLR and decreased AGR can be observed in almost all NPs, an increased PLR may indicate a malignant NP and can be used as an additional screening tool in dogs with nasal discharge due to nasal cavity pathology.

Update on olfactory neuroblastoma.

Olfactory neuroblastomas are uncommon malignancies that arise from olfactory receptor cells located high in the nasal cavity. Accurate diagnosis plays a crucial role in determining clinical results and guiding treatment decisions. Diagnosis can be a major challenge for pathologists, especially when dealing with tumours with poor differentiation. The discovery of several molecular and immunohistochemical markers would help to overcome classification difficulties. Due to the paucity of large-scale studies, standardisation of diagnosis, treatment and prediction of outcome remains a challenge. Surgical resection by endoscopic techniques with the addition of postoperative irradiation is the treatment of choice. In addition, it is advisable to consider elective neck irradiation to minimise the risk of nodal recurrence. Molecular characterisation will help not only to make more accurate diagnoses but also to identify specific molecular targets that can be used to develop personalised treatment options tailored to each patient. The present review aims to summarise the current state of knowledge on histopathological diagnosis, the molecular biology and management of this disease.

A case report on a nasal and oral cavity involving large solitary fibrous tumor and comprehensive review of case literature.

Solitary fibrous tumor (SFT) represents an uncommon spindle cell sarcoma predominantly situated within soft tissue, with a notably infrequent occurrence in the nasal cavity and paranasal sinuses. In this report, we present a case involving a middle-aged male with a sizable solitary fibrous tumor affecting both the nasal and oral cavities.

Dorsal rhinotomy in a dog with a chondro-osseous respiratory epithelial adenomatoid hamartoma: a case report.

OBJECTIVE: To describe the clinical presentation, novel surgical approach, and outcome of a dog diagnosed with chondro-osseous respiratory epithelial adenomatoid hamartoma (COREAH). ANIMAL: 5-year-old castrated male Yorkshire Terrier. CLINICAL PRESENTATION, PROGRESSION, AND PROCEDURES: The dog was presented with chronic upper respiratory noise, congestion, facial swelling, ocular discharge, and an abscess on the nasal bridge. Two CT scans were performed 4 months apart. The CT scans yielded similar results: cyst-like nasal masses with severely destructive bilateral rhinitis with extensive polyostotic bony lysis. A dorsal rhinotomy with a turbinectomy and debridement of the nasal cavity were performed. A poorly defined but extensive lesion was found occupying the entirety of the left frontal sinus as well as the nasal cavity. TREATMENT AND OUTCOME: Histopathology revealed a mass consistent with COREAH. The dog recovered well from surgery, except for self-limiting subcutaneous emphysema, and 3 weeks postoperatively was reportedly doing well, with mild nasal discharge. Stridor, nasal discharge, and sneezing episodes were reported postoperatively; however, these were improved. At 18 months postoperatively, the dog died from uncontrolled seizures while hospitalized for suspected acute hemorrhagic diarrhea syndrome at a different hospital. CLINICAL RELEVANCE: COREAH should be considered a potential cause of destructive bilateral rhinitis and bony lysis in dogs. Dorsal rhinotomy can be a surgical treatment for dogs with possible COREAH with acceptable outcome, though complete remission of clinical signs may not be achieved. This is the first clinical description of COREAH in a dog.

The role of insulinoma-associated protein 1 in predicting the progression and prognosis of human olfactory neuroblastoma in China.

OBJECTIVE: Recent studies have suggested that insulinoma-associated protein 1 (INSM1) is a useful marker for pathological diagnosis of neuroendocrine tumors. In the present study, we investigated the association between INSM1 expression and prognosis in patients with olfactory neuroblastoma (ONB) and assessed the usefulness of INSM1 as a prognostic biomarker in these patients. METHOD: Immunohistochemistry was performed on 109 ONB patients who underwent endoscopic surgery at Beijing Tong Ren Hospital (Beijing, China) between June 2006 and November 2021 Patient age at the time of surgery ranged from 10 months to 72 years (mean age, 43.55 ± 13.47 years). In total, 63 (57.8%) and 46 (42.2%) tumors occurred in male and female patients, respectively. The percentages of grade I-IV cases were 13.8% (15/109), 36.7% (40/109), 29.4% (32/109) and 20.2% (22/109), respectively. RESULTS: The expression rate (moderately/strongly positive) of INSM1 was significantly higher in high-grade (Ⅲ/Ⅳ; 83%; 45/54) than low-grade (Ⅰ/Ⅱ; 27%; 15/55) ONB cases. High expression levels of INSM1 were significantly positively associated with high pathological stage (p < 0.001), local recurrence, and death. Kaplan­Meier analysis revealed that patients with high INSM1 expression had significantly shorter disease­free survival (DFS) and mean survival (75.01 ± 10.71 vs. 158.56 ± 10.32) times, and shorter overall survival (OS). Multivariate Cox regression analysis revealed that INSM1 was an independent prognostic factor for DFS (HR: 4.963, 95%CI [2.11-10.84] p < 0.001) and OS (HR: 4.791, 95%CI [2.117-10.485], p < 0.001) after adjusting for sex, age, and tumor grade. In addition, INSM1 was an independent prognostic factor for DFS in patients treated with surgery (HR: 3.714, 95%CI [1.267-10.889], p = 0.017) and chemotherapy (HR: 5.574, 95%CI [1.584-19.612], p = 0.007). CONCLUSION: INSM1 expression had a positive association with the prognosis of patients with ONB and could serve as a prognostic biomarker in these patients.

Nasal spindle cell tumor: A case report and literature review.

BACKGROUND: Spindle cell tumors are rare and can occur in any organ or tissue. Due to their rarity the clinicopathological features and diagnostic protocols have not been adequately studied. However, it has become necessary to develop differential diagnosis of spindle cell tumors. Here, we report a case of a nasal spindle cell tumor diagnosed at our hospital in attempt to contribute to this gap in literature. KEY POINTS FROM THE CASE: A male in his 30s was admitted to our hospital with nasal obstruction that had persisted for several years. Electronic fibrolaryngoscopy revealed a smooth neoplasm within the nasal cavity. MAIN LESSONS TO BE LEARNED FROM THIS CASE REPORT: The results of this case emphasize that spindle cell tumors have large morphological variations, and it is difficult to determine the origin of tumor cells using hematoxylin and eosin staining alone. Therefore, it is necessary to improve the immunohistochemistry and combine it with clinical symptoms to diagnose the disease.

Characterizing Immune Infiltration in Esthesioneuroblastoma Subtypes Through Gene Expression Deconvolution.

BACKGROUND: Esthesioneuroblastoma (ENB) is a rare cancer deriving from the olfactory mucosa. Among the basal or neural genomic subtypes, the basal subtype is associated with poorer survival, poor differentiation, and higher levels of tumor-infiltrating immune cells (TIICs). The immune microenvironment of these ENB subtypes remains unclear. We used an established machine learning algorithm on ENB transcriptomic profiles. METHODS: The authors characterized 22 immune cell populations using the CIBERSORTx deconvolutional machine learning pipeline on RNA sequencing data from 18 ENB cases. The characterization aimed to elucidate differences in relative proportions and populations of TIICs between basal and neural ENB. RESULTS: No differences in age, Hyams, Dulguerov, IDH2 mutation, or PD-L1 expression were seen between basal and neural subtypes of ENB (P > 0.05). Also, no difference in median overall survival was appreciated (52.0 ± 13.1 months vs. 50.0 ± 43.2 months, P = 0.5). As a cohort, M2 macrophages were the most abundant subpopulation (14%) followed by naïve B cells (13%) and CD4 memory resting T cells (12%). No gross differences in CD20, CD4, or CD8 cells/mm2 were apparent on gross histology (P > 0.05). However, further analysis showed that activated CD4 memory T cells were significantly increased in the basal ENBs, whereas resting dendritic cells were increased in the neural ENB subtype. The TIIC profiles alone could not differentiate between basal and neural ENB, but did suggest immunoprofile differences. CONCLUSIONS: Basal and neural subtypes display distinct TIIC involvement, which may impact their difference in outcome. These findings provide the framework for further investigation in novel immunomodulation strategies for ENB.

A Large Pleomorphic Adenoma in Nasal Cavity Misdiagnosed as Inverted Papilloma.

Pleomorphic adenoma (PA) is a benign tumor characterized by slow-growing mixed tumors in the craniofacial area. It is relatively common in salivary glands; however, PA of the nasal cavity, which arises in the minor salivary glands, is rare. We present the case of a large PA in the nasal cavity of an adult immunocompetent woman with nasal obstruction and intermittent epistaxis. Based on preoperative radiologic examinations, she was misdiagnosed with an inverted papilloma. Endoscopic resection was performed under general anesthesia. Pathologically, the patient was confirmed to have PA, which has great cellularity and few stromal components. No complications or recurrences during the 1-year follow-up period were observed.

A multi-institutional retrospective study of 340 cases of sinonasal malignant tumor.

OBJECTIVE: Sinonasal malignant tumors (SNMT) are relatively rare among head and neck malignant tumors. Most are squamous cell carcinomas, and malignant melanomas, olfactory neuroblastomas, adenoid cystic carcinomas, sarcomas, and others also occur. The most common primary site of nasal sinus squamous cell carcinoma is the maxillary sinus. In recent years, a decrease in incidence of maxillary sinus squamous cell carcinoma (MSSCC) has been reported along with a decrease in the incidence of sinusitis. MSSCC is treated with a combination of surgery, radiation, and chemotherapy. Treatment decisions are made according to the progression of the disease, the patient's general condition, and the patient's own wishes. There are variations in treatment policies among facilities due to the specialty of staff and cooperation with other departments at each facility. We conducted a multi-institutional retrospective study to compare outcomes by treatment strategy. METHODS: In this study, 340 patients with SNMT who were treated at 13 Hospitals (Head and Neck Oncology Group (Kyoto-HNOG) ) during the 12-year period from January 2006 to December 2017 were included. There were 220 patients with squamous cell carcinoma, 32 with malignant melanoma, 21 with olfactory neuroblastoma, and 67 with other malignancies. Of the squamous cell carcinomas, 164 were of maxillary sinus origin. One hundred and forty cases of MSSCC that were treated radically were included in the detailed statistical analysis. RESULTS: There were 5 cases of cStage I, 9 cases of cStage II, 36 cases of cStage III, 74 cases of cStage IVa, and 16 cases of cStage IVb. There were 92 cases without clinical lymph node metastasis (cN(-)) and 48 cases with clinical lymph node metastasis(cN(+)). Primary tumors were treated mainly by surgery in 85 cases (Surg) and by radical radiation therapy (with or without chemotherapy) of 6-70 Gy in 55 cases(non-Surg). The 5-year overall/disease-free survival rate (OS/DFS) for MSSCC was 65.1%/51.6%. Old age, renal dysfunction, and clinical T progression were independent risk factors for OS, and renal dysfunction was an independent risk factor for DFS. In cN(-) patients, OS and DFS were significantly better in Surg group than in non-Surg group. In cN(+) patients, there was no significant difference in OS and DFS between Surg and non-Surg groups. CONCLUSION: For patients with MSSCC without lymph node metastasis, aggressive surgery on the primary tumor contributes to improved prognosis.

The Effect of Rosmarinic Acid on Wound Healing of Nasal Mucosa in the Rats.

BACKGROUND: The nose can be damaged by environmental pollutants and foreign bodies, as well as a result of trauma, infection or surgical interventions. Proper healing of the damaged nasal mucosa is important for health. OBJECTIVE: There is no study in the literature investigating the effects of rosmarinic acid on mucosal healing. The aim of this study was to investigate the effect of rosmarinic acid on nasal mucosal healing. METHODS: 21 male, adult Spraque Dawley albino rats were divided into three groups as the control group, the local treatment group in which rosmarinic acid was applied locally to the nasal mucosa, and the systemic treatment group in which rosmarinic acid was injected intraperitoneally. The wound area was obtained by creating a trauma area by inserting a 10 mm interdental brush through the right nasal nostril into the right nasal cavities of all animals. For the following 15 days, the treatment agent was applied as indicated once a day and on the 15th day the animals were decapitated and tissue samples taken from the nasal mucosa were prepared for histopathological examination. The preparations were examined in terms of cellular hyperplasia, goblet cell hypertrophy and degeneration, leukocyte infiltration, cilia loss and degeneration, edema and vascular dilatation, and they have been classified into four categories as mild (+), moderate (++), severe (+++) and very severe (++++). RESULTS: There was a significant difference between the groups in terms of all parameters evaluated, and there is a decrease in the intensity of the parameters with transition from the control group to the local group and from there to the systemic group. CONCLUSION: Systemic rosmarinic acid administration showed an enhancing effect on the healing of experimentally induced nasal mucosal injury due to its possible anti-inflammatory effect.

Impact of facility volume on survival in primary endoscopic surgery for sinonasal squamous cell carcinoma.

OBJECTIVES: To evaluate the impact of facility volume on outcomes following primary endoscopic surgical management of sinonasal squamous cell carcinoma (SNSCC). METHODS: The 2010-2016 National Cancer DataBase (NCDB) was queried for patients diagnosed with T1-T4a SNSCC surgically treated endoscopically as the primary treatment modality. Factors associated with overall survival (OS) were evaluated, including facility volume. RESULTS: A total of 330 patients who underwent endoscopic surgical management of SNSCC were treated at 356 unique facilities designated as either low-volume (LVC; treating 1-2 cases; 0-75th percentile), intermediate-volume centers (IVC; 3-4 cases total; 75th-90th percentile), or 144 high-volume (HVC; treating 5+ cases total; >90th percentile) centers. HVC treated patients with higher T staging (42.1 % vs. 29.8 %) and tumors in the maxillary sinus (26.9 % vs. 13.2 %) and ethmoid sinus (10.3 % vs. ≤8.3 %), while LVCs treated lower T stage tumors (70.2 % vs. 57.9 %) and tumors that were located in the nasal cavity (70.2-78.5 % vs. 62.8 %). On multivariable analysis, factors associated with decreased OS included higher T stage (T3/T4a vs. T1/T2; OR 1.92, 95 % CI 1.06-3.47) and older age (>65 vs. <65; OR 2.69, 95 % CI 1.62-4.49). Cases treated at high-volume centers were not associated with a higher likelihood of OS when compared to low-volume centers (OR 0.70, 95 % CI 0.36-1.35). CONCLUSIONS: HVC are treating more primary tumors of the maxillary and ethmoid sinuses and tumors with higher T stages with endoscopic approaches, although this does not appear to be associated with increased OS. SHORT SUMMARY: Sinonasal squamous cell carcinoma (SNSCC) presents late in disease process with poor prognosis. We investigated the impact of facility volume on outcomes following endoscopic treatment of SNSCC. High-volume centers treat more advanced and complex disease with comparable OS.