Histopathology of Recalcitrant Maxillary Sinusitis Necessitating Endoscopic Medial Maxillectomy

OBJECTIVES

Endoscopic medial maxillectomy (EMM) is an effective intervention for patients with recalcitrant maxillary sinusitis after previous middle meatal antrostomy. The pathophysiology of refractory maxillary sinusitis is incompletely understood. We aim to identify trends in structured histopathology (SHP) to better understand how tissue architecture changes contribute to refractory sinusitis and impaired mucociliary clearance.

METHODS

All patients who underwent EMM or standard maxillary antrostomy for recalcitrant maxillary sinusitis of various forms were included. Retrospective chart review was conducted to collect information on demographics, disease characteristics, comorbid conditions, culture data, and SHP reports. Chi-squared and logistic regression analyses were performed for SHP variables.

RESULTS

Forty-one patients who underwent EMM and 464 patients who underwent maxillary antrostomy were included. On average, the EMM cohort was 10 years older (60.9 years vs. 51.1 years; p = 0.001) and more often had a history of prior sinus procedures (73.2% vs. 40.9%; p < 0.001). EMM patients had higher rates of fibrosis (34.1% vs. 15.1%, p = 0.002), and this remained statistically significant when controlling for prior sinus procedures and nasal polyposis (p = 0.001). Cultures positive for pseudomonas aeruginosa (38.2% vs. 5.6%, p < 0.001) and coagulase negative staphylococcus (47.1% vs. 23.5%, p = 0.003) were more prevalent in the EMM group.

CONCLUSION

Fibrosis and bacterial infections with Pseudomonas and coagulase negative Staphylococcus were more prevalent in patients requiring EMM. This may contribute to the multifactorial etiology of impaired mucociliary clearance in patients with recalcitrant maxillary sinusitis.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:2646-2652, 2024.

Histopathology of Allergic Fungal Rhinosinusitis Versus Chronic Rhinosinusitis with Nasal Polyps

OBJECTIVE

Structured histopathology (SHP) is a method of analyzing sinonasal tissue to characterize endotypes of chronic rhinosinusitis with nasal polyps (CRSwNP). Allergic fungal rhinosinusitis (AFRS) shares several features with certain endotypes of CRSwNP. Our objective was to compare the histopathology of AFRS and eosinophilic CRSwNP to further understand whether they are separate endotypes or disease entities altogether.

METHODS

A retrospective review of AFRS and CRSwNP patients undergoing endoscopic sinus surgery was performed. Data were collected on demographics, comorbidities, subjective and objective severity scores, and 13-variable SHP reports. CRSwNP patients with >10 eosinophils per high-power field (eCRSwNP) were included. Chi-squared and t-tests were used for statistical analysis.

RESULTS

A total of 29 AFRS and 108 eCRSwNP patients were identified. AFRS patients were younger and more often Black. Symptom severity scores (SNOT-22, Lund-MacKay, and Lund-Kennedy) were uniform between groups. AFRS patients had a higher rate of Charcot-Leyden crystals (41.4% vs. 10.2%; p < 0.001). Severe degree of inflammation, eosinophilic inflammatory predominance, eosinophil aggregates, subepithelial edema, and basement membrane thickening were common in both groups, and their rates were not statistically significantly different between groups. Metaplasia, ulceration, fibrosis, and hyperplastic/papillary change rates were low (<30%) and similar between groups.

CONCLUSION

The SHP of eCRSwNP and AFRS are highly consistent, which suggests AFRS is a severe subtype of CRSwNP overall rather than a separate disease entity. This also lends credence to AFRS belonging on the endotypic spectrum of CRSwNP.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:2617-2621, 2024.

Tissue Eosinophilia is Superior to an Analysis by Polyp Status for the Chronic Rhinosinusitis Transcriptome: An RNA Study

OBJECTIVE

RNA sequencing (transcriptomics) is used to study biological pathways. However, the yield of data depends on comparing well-characterized cohorts. We compared tissue eosinophilia versus nasal polyp (NP) status as the metric to characterize transcriptomic mechanisms at play in eosinophilic and non-eosinophilic chronic rhinosinusitis (CRS) versus controls.

METHODS

RNA sequencing was conducted on sinonasal tissue samples of CRS and controls. Analyses were conducted based on polyp status [with nasal polyps (CRSwNP) and without nasal polyps (CRSsNP)] as well as tissue eosinophil levels per high power field (eos/hpf)[non-eosinophilic (<10 eos/hpf, neCRS) or eosinophilic (≥10 eos/hpf, eCRS)]. The yield of differentially expressed genes (DEGs) and biological pathways through Ingenuity Pathway Analysis (IPA) were compared.

RESULTS

CRS tissue differed from controls by 736 statistically significant DEGs. Both NP status and tissue eosinophilia were effective in differentiating CRS from controls and into two distinct subgroups. Statistically significant DEGs identified when comparing CRS by NP status were 60, whereas 110 DEGs were identified using eosinophil cutoff ≥10 and <10 eos/hpf. Additionally, heatmaps showed greater homogeneity within each CRS subgroup when analyzed by tissue eosinophilia versus NP status. On IPA, the IL-17 signaling pathway was significantly different only by tissue eosinophilia status, not NP status, being higher in CRS <10 eos/hpf.

CONCLUSION

Tissue eosinophilia is superior to an analysis by NP status for the study of CRS transcriptome by RNA sequencing in identifying DEGs. Classification of CRS samples by eosinophil counts agnostic of NP status may offer advantageous insights into CRS pathogenetic mechanisms.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:2480-2489, 2023.

Defining the Allergic Endotype of Chronic Rhinosinusitis by Structured Histopathology and Clinical Variables

BACKGROUND

Atopy has a strong association with chronic rhinosinusitis (CRS).

OBJECTIVE

To understand whether patients with atopy and CRS can be defined by markers of tissue histopathology, systemic biomarkers, and clinical factors, which may guide their response to new pharmacologic agents.

METHODS

In a retrospective cohort of CRS patients who underwent functional endoscopic sinus surgery, a structured histopathology report consisting of 12 variables, comorbid conditions, preoperative total serum IgE levels, and preoperative modified Lund-Kennedy endoscopic and sinonasal outcome test (SNOT-22) scores were compared between atopic CRS (aCRS) and non-aCRS control patients in a multivariable model.

RESULTS

A total of 380 CRS patients were enrolled, 286 of whom had comorbid atopy (aCRS). Compared with non-aCRS, aCRS patients had significantly higher preoperative total SNOT-22 scores (40.45 ± 22.68 vs 29.70 ± 20.68, P = .015) and symptom-specific SNOT-22 scores in all domains except psychological dysfunction. Relative to non-aCRS, aCRS patients had increased tissue eosinophilia (P < .0001), eosinophil aggregates (P < .0001), Charcot-Leyden crystals (P < .04), fibrosis (P < .02), total serum IgE levels (P < .04), polyploid disease (P < .001), and a prevalence of comorbid asthma (P < .0001) and aspirin exacerbated respiratory disease (AERD) (P < .003). Patients with aCRS demonstrated increased tissue eosinophilia compared with non-aCRS patients even after controlling for polypoid disease, asthma, and AERD.

CONCLUSION

In the context of CRS, atopy appears to be a specific predictor of CRS severity linked to specific histopathologic variables, including enhanced eosinophilic aggregates. Moving forward, allergic status may be a useful way to identify an atopic endotype of CRS patients. Furthermore, after surgery, patients are often maintained on intranasal corticosteroids. In patients whose disease is unresponsive to steroids, we may look to atopic status to identify another management therapy. Atopic CRS patients, irrespective of polyp and asthmatic status, could be optimal candidates for biologic agents such as T-helper cell, eosinophil, and/or IgE-targeted therapies.

Inter-pathologist Agreement on Structured Histopathology Reporting in Chronic Rhinosinusitis

BACKGROUND

Structured histopathology reporting is increasingly being utilized in rhinology to characterize endotypes in chronic rhinosinusitis and guide management decisions after sinus surgery.

OBJECTIVE

The goal of this investigation is to evaluate inter-observer agreement in structured histopathology reporting.

METHODS

Two experienced head and neck pathologists independently compiled structured histopathology reports for tissue samples collected during functional endoscopic sinus surgery. Cohen's standard kappa (κ) coefficients were calculated for each histopathologic variable to assess inter-pathologist agreement.

RESULTS

A total of 92 cases were analyzed. Substantial inter-pathologist agreement was reached on tissue eosinophil count (κ = 0.64, P < .001), the presence of eosinophil aggregates (κ = 0.62, P < .001), and the presence of fungal elements (κ = 0.74, P < .001). There was moderate agreement on the degree of inflammation (κ = 0.56, P < .001) and the presence of squamous metaplasia (κ = 0.46, P < .001). There was fair agreement on the presence of neutrophil infiltrates (κ = 0.33, P < .001), the presence of hyperplastic changes (κ = 0.40, P < .001), and the presence of fibrosis (κ = 0.24, P = .022). There was only slight agreement on the degree of subepithelial edema (κ = 0.20, P = .008). The κ coefficients for basement membrane thickening and mucosal ulceration were not statistically significant.

CONCLUSION

High inter-pathologist agreement was demonstrated for several salient histopathologic variables, including tissue eosinophil count and the presence of eosinophil aggregates. However, refining the definitions of certain histopathologic variables may improve the reproducibility of structured histopathology reporting.

Structured histopathology for endotyping and planning rational treatment in chronic rhinosinusitis

In chronic rhinosinusitis (CRS), endotyping, being based on the pathogenic mechanism, provides a precise picture appropriate for use in clinical practice. Structured histopathological examination of CRS is considered a necessary step in efforts to establish its pathogenesis and improve our endotyping capabilities. Herein we discuss the associations between histopathology and clinical characteristics of CRS patients to assist medical and surgical treatment choices.