Personalized Approach to Olfactory Neuroblastoma Care.

Olfactory neuroblastoma (ONB) is an uncommon neuroendocrine malignancy arising from the olfactory neuroepithelium. ONB frequently presents with nonspecific sinonasal complaints, including nasal obstruction and epistaxis, and diagnosis can be obtained through a combination of physical examination, nasal endoscopy, and computed tomography and magnetic resonance imaging. Endoscopic resection with negative margins, with or without craniotomy, as necessary, is the standard of care for definitive treatment of ONB. Regional metastasis to the neck is often detected at presentation or may occur in a delayed fashion and should be addressed through elective neck dissection or radiation. Adjuvant radiotherapy should be considered, particularly in the case of high grade or tumor stage, as well as positive surgical margins. Systemic therapy is an area of active investigation in both the neoadjuvant and adjuvant setting, with many advocating in favor of induction chemotherapy for significant orbital or intracranial involvement prior to surgical resection. Various targeted immunotherapies are currently being studied for the treatment of recurrent or metastatic ONB. Prolonged locoregional and distant surveillance are indicated following definitive treatment, given the tendency for delayed recurrence and metastasis.

Machine Learning for Predictive Analysis of Otolaryngology Residency Letters of Recommendation.

INTRODUCTION: Letters of recommendation (LORs) are a highly influential yet subjective and often enigmatic aspect of the residency application process. This study hypothesizes that LORs do contain valuable insights into applicants and can be used to predict outcomes. This pilot study utilizes natural language processing and machine learning (ML) models using LOR text to predict interview invitations for otolaryngology residency applicants. METHODS: A total of 1642 LORs from the 2022-2023 application cycle were retrospectively retrieved from a single institution. LORs were preprocessed and vectorized using three different techniques to represent the text in a way that an ML model can understand written prose: CountVectorizer (CV), Term Frequency-Inverse Document Frequency (TF-IDF), and Word2Vec (WV). Then, the LORs were trained and tested on five ML models: Logistic Regression (LR), Naive Bayes (NB), Decision Tree (DT), Random Forest (RF), and Support Vector Machine (SVM). RESULTS: Of the 337 applicants, 67 were interviewed and 270 were not interviewed. In total, 1642 LORs (26.7% interviewed) were analyzed. The two best-performing ML models in predicting interview invitations were the TF-IDF vectorized DT and CV vectorized DT models. CONCLUSION: This preliminary study revealed that ML models and vectorization combinations can provide better-than-chance predictions for interview invitations for otolaryngology residency applicants. The high-performing ML models were able to classify meaningful information from the LORs to predict applicant interview invitation. The potential of an automated process to help predict an applicant's likelihood of obtaining an interview invitation could be a valuable tool for training programs in the future. LEVEL OF EVIDENCE: N/A Laryngoscope, 2024.

Utilizing Histopathology to Predict Success with Macrolide Therapy in CRS Patients.

There is currently interest regarding CRSsNP patients with refractory symptomatology following functional endoscopic sinus surgery, and which of these patients can derive benefit from low-dose macrolide therapy. In the present study, we analyze a cohort of over fifty CRSsNP patients on macrolide therapy; structured histopathological findings at the time of surgery were analyzed against the success of macrolide treatment. Independently, fibrosis, absence of squamous metaplasia, absence of eosinophilia, presence of neutrophilic infiltrate, and lymphoplasmocytic predominance were all associated with objective success of macrolide treatment; these findings may allow clinicians to more appropriately select patients for this therapy.

5-Aminolevulinic Acid Fluorescence-Guided Surgery in Head and Neck Squamous Cell Carcinoma.

OBJECTIVES: To determine the utility of 5-aminolevulinic acid (5-ALA) fluorescence for resection of head and neck carcinoma. METHODS: In this prospective pilot trial, 5-ALA was administered as an oral suspension 3-5 h prior to induction of anesthesia for resection of head and neck squamous cell carcinoma (HNSCC). Following resection, 405 nm blue light was applied, and fluorescence of the tumor as well as the surgical bed was recorded. Specimen fluorescence intensity was graded categorically as none (score = 0), mild (1), moderate (2), or robust (3) by the operating surgeon intraoperatively and corroborated with final pathologic diagnosis. RESULTS: Seven patients underwent resection with 5-ALA. Five (83%) were male with an age range of 33-82 years (mean = 60). Sites included nasal cavity (n = 3), oral cavity (n = 3), and the larynx (n = 1). All specimens demonstrated robust fluorescence when 5-ALA was administered 3-5 h preoperatively. 5-ALA fluorescence predicted the presence of perineural invasion, a positive margin, and metastatic lymphadenopathy. Two patients had acute photosensitivity reactions, and one patient had a temporary elevation of hepatic enzymes. CONCLUSIONS: 5-ALA induces robust intraoperative fluorescence of HNSCC, capable of demonstrating a positive margin, perineural invasion, and metastatic nodal disease. Although no conclusions are there about the safety of this drug in the head and neck cancer population, our study parallels the extensive safety data in the neurosurgical literature. Future applications may include intraoperative assessment of margin status, diagnostic accuracy, and impacts on survival. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:741-748, 2024.

Gabapentin and postoperative pain and opioid consumption: A double-blind randomized controlled trial of perioperative pain management for sinus surgery.

BACKGROUND: The link between post-operative narcotic prescription and opioid misuse has spurred a nationwide effort to reduce perioperative opioid use. Previous work has suggested that perioperative gabapentin may reduce post-operative pain and opioid consumption across different procedures, although the optimal regimen remains to be defined. METHODS: Chronic rhinosinusitis (CRS) patients undergoing functional endoscopic sinus surgery (FESS) with or without septoplasty were randomized to receive a 7-day pre- and post-operative course of placebo or gabapentin, starting at 300 mg daily and titrated to 300 mg three times daily, in a double-blind fashion. Primary endpoint was pain level using a validated visual analog scale (VAS). Secondary endpoints included post-operative opioid consumption and side effects, as well as modified Lund-Kennedy endoscopy, Lund-Mackay, and SNOT-22 scores. RESULTS: Analysis of 35 patients (20 gabapentin, 15 control) showed no significant difference in mean postoperative VAS (p = 0.18) or postoperative opioid consumption between the placebo and gabapentin groups (2.3 and 4.8 oxycodone tablets respectively, p = 0.18). 15 of 35 patients did not require any post-operative oxycodone tablets, and only two patients required more than six tablets. CONCLUSION: Preliminary results show no significant change in pain after FESS with or without septoplasty in patients taking 7-day pre- and post-operative gabapentin versus placebo. Results also showed no significant difference in opioid consumption between the treatment and placebo groups. Post-operative pain scores and opioid requirements are both quite low following FESS. Many patients do not need opioids at all, suggesting that routine initial post-operative opioid prescriptions can be limited accordingly.

Utility of a LangChain and OpenAI GPT-powered chatbot based on the international consensus statement on allergy and rhinology: Rhinosinusitis.

KEY POINTS: We created a LangChain/OpenAI API-powered chatbot based solely on International Consensus Statement of Allergy and Rhinology: Rhinosinusitis (ICAR-RS). The ICAR-RS chatbot is able to provide direct and actionable recommendations. Utilization of consensus statements provides an opportunity for AI applications in healthcare.

Omega-3 Fatty Acid Supplementation for the Treatment of Persistent COVID-Related Olfactory Dysfunction.

OBJECTIVE: To evaluate the efficacy of omega-3 fatty acid (O3FA) supplementation in the treatment of COVID-related olfactory dysfunction (OD). METHODS: Patients with laboratory-confirmed or clinically-suspected COVID-19 infection and new-onset OD from August 2020 to November 2021 were prospectively recruited. Patients with quantitative OD, defined as a brief smell identification test (BSIT) score of 9 or less, were eligible for study inclusion. The experimental group received 2 g of O3FA supplementation, while the control group received an identical placebo to be taken daily for 6 weeks. The primary outcome was a change in BSIT score between the initial and 6-week follow-up tests. RESULTS: One hundred and seventeen patients were included in the analysis, including 57 patients in the O3FA group and 60 in the placebo group. O3FA group patients demonstrated a mean BSIT improvement of 1.12 ± 1.99 compared to 0.68 ± 1.86 in the placebo group (p = 0.221). Seventy-seven patients, 42 within the O3FA group and 35 in the placebo group, completed a follow-up BSIT survey at an average of 717.8 days from study onset. At long-term follow-up, there was an average BSIT score improvement of 1.72 within the O3FA group compared to 1.76 within the placebo group (p = 0.948). CONCLUSION: Among patients with persistent COVID-related OD, our study showed no clear evidence of relative short-term or long-term olfactory recovery among patients receiving high doses of O3FA supplementation.

A natural language processing approach to uncover patterns among online ratings of otolaryngologists.

BACKGROUND: Patients increasingly use physician rating websites to evaluate and choose potential healthcare providers. A sentiment analysis and machine learning approach can uniquely analyse written prose to quantitatively describe patients' perspectives from interactions with their physicians. METHODS: Online written reviews and star scores were analysed from Healthgrades.com using a natural language processing sentiment analysis package. Demographics of otolaryngologists were compared and a multivariable regression for individual words was performed. RESULTS: This study analysed 18 546 online reviews of 1240 otolaryngologists across the USA. Younger otolaryngologists (aged less than 40 years) had higher sentiment and star scores compared with older otolaryngologists (p < 0.001). Male otolaryngologists had higher sentiment and star scores compared with female otolaryngologists (p < 0.001). 'Confident', 'kind', 'recommend' and 'comfortable' were words associated with positive reviews (p < 0.001). CONCLUSION: Positive bedside manner was strongly reflected in better reviews, and younger age and male gender of the otolaryngologist were associated with better sentiment and star scores.

Implementation of a Streamlined Care Pathway to Reduce Cost and Length of Stay for Patients Undergoing Endoscopic Transsphenoidal Pituitary Surgery.

BACKGROUND: We implemented a streamlined care pathway for patients undergoing endoscopic transsphenoidal (TSA) pituitary surgery. Select patients are recovered in the postanesthesia care unit and transferred to a step-down unit for intermediate neurologic care (INCU), with clinicians trained to manage cerebrospinal fluid leak, diabetes insipidus (DI), and other complications. METHODS: We evaluated all TSA surgeries performed at 1 academic medical center from 7th January, 2017 to 30th March, 2020, collecting patient factors, tumor characteristics, cost variables, and outcomes. The INCU pathway was implemented on 7th January 2018. Pathway patients were compared with nonpathway patients across the study period. Outcomes were assessed using multivariate regression, adjusting for patient and surgical characteristics, including intraoperative cerebrospinal fluid leak, postoperative DI, and tumor dimensions. RESULTS: One hundred eighty-seven patients were identified. Seventy-nine were on the INCU pathway. Mean age was 53.5 years. Most patients were male (66%), privately insured (62%), and white (66%). Mean total cost of admission was $27,276. Mean length of stay (LOS) was 3.97 days. Use of the INCU pathway was associated with total cost reduction of $6376.33 (P < 0.001, 95% confidence interval [CI]: $3698.21-$9054.45) and LOS reduction by 1.27 days (P = 0.008, 95% CI: 0.33-2.20). In-hospital costs were reduced across all domains, including $1964.87 in variable direct labor costs (P < 0.001, 95% CI: $1142.08-$2787.64) and $1206.52 in variable direct supply costs (P < 0.001, 95% CI: $762.54-$1650.51). Pathway patients were discharged earlier despite a higher rate of postoperative DI (25% vs. 11%, P = 0.011), with fewer readmissions (0% vs. 6%, P = 0.021). CONCLUSIONS: A streamlined care pathway following TSA surgery can reduce in-hospital costs and LOS without compromising patient outcomes.

In-Hospital Cost Comparison for Open Versus Endoscopic Endonasal Approach for Meningioma Resection.

OBJECTIVE: To determine the in-hospital cost implications of an endoscopic expanded endonasal approach (EEEA) for meningioma resection relative to the open transcranial approach. METHODS: All anterior skull base meningioma surgeries performed over a period from January 1st, 2015 to October 31th, 2017 were evaluated. The electronic medical record was reviewed for patient factors, tumor characteristics, and cost variables associated with each hospital stay and univariate analysis was performed using R software. All cost data were converted into August 2021-equivalent dollar amounts using the United States Bureau of Labor Statistics consumer price index. RESULTS: Thirty-five patients met study criteria, including 27 patients undergoing an open transcranial approach and 8 undergoing an EEEA. Average length of stay for patients undergoing an open approach was 9.3 days compared to 5.6 within the EEEA group (P = .126). The average total in-hospital cost of patient undergoing an EEEA was $35417.1 compared to $46406.9 among patients undergoing an open transcranial approach (P = .168). On univariate analysis, the cost of an open transcranial approach relative to the EEEA was $10989.8 (P = .411). CONCLUSIONS: The open transcranial approach remained the dominant surgical approach to anterior skull base meningiomas over our study time period. However, despite limited patient numbers the EEEA was associated with decreased total in-hospital costs.

In-Hospital Costs for Open versus Endoscopic Endonasal Approach for Craniopharyngioma Resection.

OBJECTIVE: To determine the in-hospital cost implications of an expanded endoscopic endonasal approach (EEEA) for craniopharyngioma resection relative to the traditional open transcranial approach. METHODS: All craniopharyngioma surgeries performed at a single institution over a period from January 1st 2001 to October 31th 2017 were evaluated. The electronic medical record was reviewed for patient factors, tumor characteristics, and cost variables associated with each hospital stay and univariate regression analysis was performed using R software. RESULTS: Thirty-six patients met study criteria, including 22 undergoing an open approach and 14 undergoing an EEEA. There was a significantly longer average length of stay among patients undergoing open resection (21.5 vs. 10.6 days, p = 0.024). The average total in-hospital cost of a patient undergoing an EEEA was $58979.3 compared to $89142.3 for an open approach (p = 0.127). On univariate regression analysis, the total in-hospital cost for a patient undergoing an open approach relative to an EEEA was $30163.0 (p = 0.127). The open approach was exclusively performed from study onset until April 2010 (16 patients). From April 2010 to August 2013, 6 open approaches and 5 EEEA were performed. The EEEA has been exclusively performed from August 2013 until the conclusion of our study period (9 patients). CONCLUSIONS: There has been a shift toward surgical resection of craniopharyngioma via an EEEA approach for amenable tumors. Our study demonstrates that the EEEA has become the preferred surgical approach at our institution, and shows that the EEEA is associated with shorter postoperative length of stay and lower total in-hospital cost. Laryngoscope, 133:83-87, 2023.

Sinonasal Issues After Maxillectomy With Free Flap Reconstruction: Incidence and Clinical Approach.

OBJECTIVE: To characterize the clinical features associated with sinonasal complaints after maxillectomy with free flap reconstruction as well as propose a screening and treatment algorithm. METHODS: Retrospective review of patients who underwent maxillectomy and free flap reconstruction at a tertiary care center. RESULTS: Fifty-eight patients were included, 25 (43.1%) of them had documented sinonasal complaints postoperatively. Eleven patients subsequently underwent revision surgery for sinonasal complaints. Among the 25 patients with sinonasal complaints, 22 patients (88.0%) had nasal crusting, 17 (68.0%) had nasal obstruction, 12 (48.0%) had rhinorrhea, 9 (36.0%) had facial pain or pressure, and 7 (28.0%) had foul odor. Twenty-two patients (88.0%) had multiple sinonasal complaints. There was a higher incidence of both sinonasal complaints and surgical intervention in patients who underwent adjuvant radiation, but this was not statistically significant (47.7% vs 28.6%, P = .235; 29.4% vs 7.1%, P = .265). CONCLUSIONS: Sinonasal complaints are common following free flap reconstruction for a maxillectomy defect and should be screened for at postoperative visits, with early referral to a rhinologist for consideration of endoscopic sinus surgery. Nonsurgical treatment strategies include large-volume nasal saline irrigations, xylitol irrigations for persistent inflammatory symptoms, and culture-directed antibiotic irrigations for persistent infectious symptoms. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:67-72, 2022.

Clinical Features of Parosmia Associated With COVID-19 Infection.

OBJECTIVE: To characterize the clinical features, risk factors, symptom time-course, and quality of life implications for parosmia among coronavirus disease (COVID)-related olfactory dysfunction patients. METHODS: Individuals with olfactory dysfunction associated with laboratory-confirmed or clinically suspected COVID-19 infection were recruited from otolaryngology and primary care practices over a period from August 2020 to March 2021. Participants completed olfactory dysfunction and quality of life surveys. RESULTS: A total of 148 (64.1%) of 231 respondents reported parosmia at some point. Parosmia developed within 1 week of any COVID-19 symptom onset in 25.4% of respondents, but more than 1 month after symptom onset in 43.4% of respondents. Parosmia was associated with significantly better quantitative olfactory scores on Brief Smell Identification Test (8.7 vs. 7.5, P = .006), but demonstrated worse quality of life scores, including modified brief Questionnaire of Olfactory Dysfunction-Negative Statements and Sino-Nasal Outcome Test-22 scores (12.1 vs. 8.5, P < .001; 26.2 vs. 23.2, P = .113). Participants who developed parosmia at any point were significantly younger and less likely to have history of chronic sinusitis than those who did not develop parosmia (40.2 vs. 44.9 years, P = .007; 7.2% vs. 0.7%, P = .006). CONCLUSION: COVID-19-associated olfactory dysfunction is frequently linked with development of parosmia, which often presents either at onset of smell loss or in a delayed fashion. Despite better quantitative olfactory scores, respondents with parosmia report decreased quality of life. A majority of respondents with persistent parosmia have sought treatment. LEVEL OF EVIDENCE: 3 Laryngoscope, 132:633-639, 2022.

Implementation of a 4-dimensional computed tomography protocol for parathyroid adenoma localization.

PURPOSE: To present the results of our implementation of a four-dimensional computed tomography- (4DCT) based parathyroid localization protocol for primary hyperparathyroidism at a safety net hospital. METHODS: We performed a retrospective review of all patients who underwent parathyroidectomy for primary hyperparathyroidism at Elmhurst Hospital Center from June 2016 - September 2019. Patients treated prior to the implementation of 4DCT during October 2018 served as historical controls for comparison. Imaging-related costs and hospital charges were obtained from the Radiology Department for each patient. RESULTS: Forty-two patients underwent parathyroid surgery during the study period. Twenty patients had undergone 4DCT while 22 had nuclear medicine studies with or without ultrasonography. The sensitivity and specificity of 4DCT was 90.4% and 100% respectively, compared to 63% and 93.7% for nuclear imaging studies and 41% and 95% for ultrasound. The mean number of glands explored was significantly less in the 4DCT group, 1.8 ± 1.19 versus 2.77 ± 1.26 (p = 0.01). There was no increase in infrastructure or personnel costs associated with 4DCT implementation. CONCLUSIONS: 4DCT represents an increasingly common imaging modality for pre-operative parathyroid localization. Here we demonstrate that 4DCT is associated with a reduction in the number of glands explored and enables minimally invasive parathyroid surgery. 4DCT is a cost-effective and clinically sound localization study for parathyroid localization in an urban safety-net hospital.

Drivers of In-Hospital Costs Following Endoscopic Transphenoidal Pituitary Surgery.

OBJECTIVE: To characterize the patient and clinical factors that determine variability in hospital costs following endoscopic transphenoidal pituitary surgery. METHODS: All endoscopic transphenoidal pituitary surgeries performed from January 1, 2015, to October 24, 2017, with complete data were evaluated in this retrospective single-institution study. The electronic medical record was reviewed for patient factors, tumor characteristics, and cost variables during each hospital stay. Multivariate linear regression was performed using Stata software. RESULTS: The analysis included 190 patients and average length of stay was 4.71 days. Average total in-hospital cost was $28,624 (95% confidence interval $25,094-$32,155) with average total direct cost of $19,444 ($17,136-$21,752) and total indirect cost of $9181 ($7592-$10,409). On multivariate regression, post-operative cerebrospinal fluid (CSF) leak was associated with a significant increase in all cost variables, including a total cost increase of $40,981 ($15,474-$66,489, P = .002). Current smoking status was associated with an increased total cost of $20,189 ($6,638-$33,740, P = .004). Self-reported Caucasian ethnicity was associated with a significant decrease in total cost of $6646 (-$12,760 to -$532, P = .033). Post-operative DI was associated with increased costs across all variables that were not statistically significant. CONCLUSIONS: Post-operative CSF leak, current smoking status, and non-Caucasian ethnicity were associated with significantly increased costs. Understanding of cost drivers of endoscopic transphenoidal pituitary surgery is critical for future cost control and value creation initiatives. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:760-764, 2021.

The impact of expanded endonasal skull base surgery on midfacial growth in pediatric patients.

OBJECTIVE: Surgical resection of skull base tumors in children is increasingly accomplished through an expanded endonasal approach (EEA). We aim to evaluate the potential effect of the EEA on midfacial growth as a result of iatrogenic damage to nasal growth zones. METHODS: We performed a retrospective review of children undergoing craniopharyngioma resection via an open transcranial or EEA. Pre- and postoperative magnetic resonance imaging was evaluated for growth in four midfacial measurements based on established cephalometric landmarks: anterior midface height, posterior midface height, palatal length, and sella-nasion distance. Statistical analysis was conducted using a mixed-effects linear regression model. RESULTS: Twenty-two patients underwent an EEA (n = 12) or open transcranial approach (n = 10) for tumor resection with 3 years of imaging follow-up. There was no difference in midfacial growth between groups for each measurement. Compared to the open group, patients undergoing EEA demonstrated relative anterior midface height growth of -0.42 mm (P = 0.880), posterior midface height growth of -0.44 mm (P = 0.839), palatal length growth of 0.35 mm (P = 0.894), and sella-nasion distance growth of -2.16 (P = 0.365). CONCLUSION: We found no difference in midfacial growth measurements between patients undergoing craniopharyngioma resection via an EEA and the open transcranial route after 3 years of imaging follow-up. Preliminary results on midfacial growth demonstrate that the EEA is a safe alternative to traditional transcranial approaches for the pediatric population. Further investigation with larger sample size and longer duration of follow-up is warranted to more thoroughly investigate the long-term implications of the EEA to the skull base. LEVEL OF EVIDENCE: 3 Laryngoscope, 130:338-342, 2020.

Factors Associated With Facial Nerve Paresis Following Gamma Knife for Vestibular Schwannoma.

OBJECTIVE: Evaluate the incidence of and potential contributory factors to facial nerve paresis and other cranial neuropathies (CN) following stereotactic radiosurgery with Gamma Knife (GK) for primary treatment of vestibular schwannoma (VS). STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral center. PATIENTS: Charts were reviewed for all adult patients receiving primary GK treatment for unilateral VS between 2005 and 2013. Patients with NF2 or previous surgery were excluded from analysis. INTERVENTION: GK radiosurgery. MAIN OUTCOME MEASURES: The incidence of new-onset facial nerve paresis after primary GK treatment of VS was evaluated. Secondary endpoints included other cranial neuropathies. RESULTS: One hundred thirty-three patients with VS received primary GK therapy. Posttreatment CN developed in 33 patients (24.8%). Twelve patients (9.0%) experienced trigeminal paresthesia, 11 (8.3%) developed sudden sensorineural hearing loss (SSNHL) requiring steroids, and seven (5.3%) demonstrated facial paresis. The mean maximum cochlear dose was 15.49 Gy in patients with facial paresis compared with 12.42 Gy in subjects without facial paresis (p = 0.032). Subjects with facial paresis were more likely to have a lateral tumor without fundal fluid on magnetic resonance imaging (MRI) (71%) compared with subjects without facial paresis (43%). CONCLUSIONS: In the treatment of VS with primary GK, maximum cochlear dose was significantly associated with facial paresis. Laterally extending tumors without fundal fluid on MRI experienced higher rates of facial paresis. These factors should be considered during GK treatment planning for VS.

Clinical and Radiographic Characteristics of Sinonasal Posttransplant Lymphoproliferative Disorder and Invasive Fungal Sinusitis.

BACKGROUND: Sinonasal posttransplant lymphoproliferative disorder (PTLD) is a serious but uncommon complication of solid organ and hematopoietic stem cell transplantation that can overlap in many features with invasive fungal sinusitis (IFS). OBJECTIVE: To identify clinical, laboratory, and radiographic features that may help to differentiate sinonasal IFS and PTLD in the posttransplant population. METHODS: We performed a retrospective chart review of patients with posttransplant sinonasal PTLD and IFS to evaluate for clinical, laboratory, and imaging characteristics. RESULTS: A total of 4 patients with sinonasal PTLD and 10 posttransplant IFS patients were evaluated. A total of 2 of 4 PTLD patients presented with a symptom duration of greater than 3 months compared to none in the IFS group (p = 0.07). Mean absolute neutrophil count (ANC) was 2,976 per mm3 (range 2,488-3,462) in the PTLD group compared to 773 per mm3 (range 0.0-2,744) in the IFS group (p = 0.01). Both PTLD lesions with available diffusion-weighted imaging demonstrated diffusion restriction on magnetic resonance im-aging (MRI) compared to zero of the IFS lesions (p = 0.10). No PTLD lesions demonstrated mucosal infarcts compared to three of seven IFS lesions (p = 0.23). CONCLUSION: IFS was associated with a significantly lower ANC at the time of diagnosis compared to PTLD. Additionally, three other measures trend towards association with their respective pathology. PTLD typically has a more chronic time course than IFS, diffusion restriction on MRI is predominantly associated with PTLD patients, and mucosal infarct on MRI is more suggestive of IFS. Additionally, all cases of sinonasal PTLD arose following solid organ transplantation. These factors may assist clinicians during diagnosis.