[Sclerosing mucoepidermoid carcinoma with eosinophilia of thyroid gland]. / Skleroziruyushchii mukoepidermoidnyi rak shchitovidnoi zhelezy s eozinofiliei stromy.

Sclerosing mucoepidermoid carcinoma with stromal eosinophilia of thyroid gland is represented less than 100 cases in the world literature. We present a rare case of sclerosing mucoepidermoid carcinona with stromal eosinophilia in a 69-year-old woman who has been observed for multinodular goiter for more than 3 years. Cytological examination revealed a picture most of all corresponding to a malignant neoplasm (Bethesda V). The patient underwent a thyroidectomy. Pathomorphological examination revealed a neoplasm of mixed structure with foci of cribriform structures and squamous metaplasia with areas of keratinization. According to the IHC study, the expression of TTF-1, p63, cytokeratins 5/6 were positive, while there were no expression of thyroglobulin with its positive reaction in the thyroid tissue. Additional histochemical staining with Alcian blue revealed a positive reaction with a homogeneous acellular substance of the tumor. A comprehensive morphological study with the use of additional stains made it possible to accurately establish the diagnosis, which will determine the further tactics of managing the patient.

Individual exposure of ambient particulate matters and eosinophilic chronic rhinosinusitis with nasal Polyps: Dose-Response, mediation effects and recurrence prediction.

PURPOSE: We evaluated the association between ambient particulate matter (PM) exposure and eosinophilic chronic rhinosinusitis with nasal polyps (CRSwNP), and predicted the CRSwNP recurrence risk using machine learning algorithms. METHODS: In total, 1,086 patients with CRSwNP were recruited from nine hospitals in China during 2014-2019. The average annual concentrations of ambient PMs before surgery were assessed using satellite-based daily concentrations of PM2.5 and PM10 for a 1 × 1-km2 area. Linear regression and logistic regression models were used to evaluate the associations of PM exposure with eosinophilia and risks of eosinophilic CRSwNPs. In addition, mediation effect analysis was used to validate the interrelationships of the aforementioned factors. Finally, machine learning algorithms were used to predict the recurrence risks of CRSwNPs. RESULTS: There was a significantly increased risk of eosinophilic CRSwNPs with each 10 µg/m3 increase in PMs, with odds ratios (ORs) of 1.039 (95% confidence interval [CI] = 1.007-1.073) for PM10 and 1.058 (95% CI = 1.007- 1.112) for PM2.5. Eosinophils had a significant mediation effect, which accounted for 52% and 35% of the relationships of CRSwNP recurrence with PM10 and PM2.5, respectively. Finally, we developed a naïve Bayesian model to predict the risk of CRSwNP recurrence based on PM exposure, inflammatory data, and patients' demographic factors. CONCLUSIONS: Increased PM exposure is associated with an increased risk of eosinophilic CRSwNP in China. Therefore, patients with eosinophilic CRSwNP should reduce PM exposure to mitigate its harmful impacts.

The roles of eosinophils and interleukin-5 in the pathophysiology of chronic rhinosinusitis with nasal polyps.

Chronic rhinosinusitis with nasal polyps (CRSwNP) is generally associated with eosinophilic tissue infiltration linked to type 2 inflammation and characterized by elevated levels of interleukin (IL)-5 and other type 2 inflammatory mediators. Although distinct and overlapping contributions of eosinophils and IL-5 to CRSwNP pathology are still being explored, they are both known to play an important role in NP inflammation. Eosinophils secrete numerous type 2 inflammatory mediators including granule proteins, enzymes, cytokines, chemokines, growth factors, lipids, and oxidative products. IL-5 is critical for the differentiation, migration, activation, and survival of eosinophils but is also implicated in the biological functions of mast cells, basophils, innate lymphoid cells, B cells, and epithelial cells. Results from clinical trials of therapeutics that target type 2 inflammatory mediators (including but not limited to anti-IL-5, anti-immunoglobulin-E, and anti-IL-4/13) may provide further evidence of how eosinophils and IL-5 contribute to CRSwNP. Finally, the association between eosinophilia/elevated IL-5 and greater rates of NP recurrence after endoscopic sinus surgery (ESS) suggests that these mediators may have utility as biomarkers of NP recurrence in diagnosing and assessing the severity of CRSwNP. This review provides an overview of eosinophil and IL-5 biology and explores the literature regarding the role of these mediators in CRSwNP pathogenesis and NP recurrence following ESS. Based on current published evidence, we suggest that although eosinophils play a key role in CRSwNP pathophysiology, IL-5, a cytokine that activates these cells, also represents a pertinent and effective treatment target in patients with CRSwNP.

Age related non-type 2 inflammation and its association with treatment outcome in patients with chronic rhinosinusitis with nasal polyp in Korea.

This study aimed to investigate the effect of age in patients with chronic rhinosinusitis with nasal polyp (CRSwNP). 269 patients were divided into eosinophilic and non-eosinophilic groups based on tissue eosinophilia, defined by eosinophils accounting for more than 20% of the total inflammatory cells. Patients were then further divided into younger and older groups based on the age of 35 years. Clinical characteristics including blood eosinophil, Lund Mackay score, and modified Lund-Kennedy (mLK) scores were compared. Levels of 14 cytokines from nasal tissues of an additional 78 patients were analyzed. Tissue eosinophilia was significantly associated with age and the proportion of non-eosinophilic CRSwNP was significantly higher in younger patients as compared to older patients (79.2% vs 56.6%). There was no difference in clinical characteristics and cytokine levels between the younger and older patients with eosinophilic CRSwNP. In contrast, in patients with non-eosinophilic CRSwNP, younger patients had significantly lower preoperative blood eosinophils and higher mLK scores at three and six months, postoperatively, compared to older patients. Alpha-1 antitrypsin and IL-5 levels were significantly lower in younger patients than in older patients in non-eosinophilic CRSwNP. This study suggests a potential association between age, non-type 2 inflammation and treatment outcome in CRSwNP.

Alteration of Histopathology in Recurrent Nasal Polyps.

OBJECTIVE: The objective of this study was to analyze the histopathologic changes in recurrent nasal polyps (NPs) in terms of tissue inflammatory cells infiltration and mucosal remodeling. METHODS: Thirty-five patients with primary NPs requiring a revision surgery during follow-up and a matched control group of 35 primary NP patients without recurrence were retrospectively enrolled. Histopathologic examination was performed of tissue inflammatory cells, subepithelial edema, epithelial cell hyperplasia, basement membrane thickness, and fibrosis. RESULTS: The mean eosinophil and neutrophil counts, proportions of eosinophil and neutrophil, as well as total inflammatory cell count were significantly higher in the recurrent group than those in the controls. Higher subepithelial edema was seen in the recurrent group. Within the recurrent group, the mean tissue eosinophil count and relative eosinophilia reduced from the first operation to revision surgery, whereas neutrophil count and proportion, and total inflammatory cell counts remained unchanged. Subepithelial edema and epithelial cell hyperplasia were significantly reduced after the first surgical procedure. CONCLUSION: NP recurrence is associated with higher inflammatory grade (especially in eosinophilia and neutrophilia). Surgical and corticoid treatments may have an impact on mucosal histopathologic changes but need further certification.

Anatomical Features Around Eustachian Tube in Eosinophilic Otitis Media With Eosinophilic Sinusitis.

OBJECTIVES/HYPOTHESIS: This study investigated the relationships between anatomical findings around the eustachian tube (ET) and eosinophilic otitis media (EOM) accompanied by eosinophilic chronic rhinosinusitis (ECRS). STUDY DESIGN: This study employed axial, coronal, sagittal and oblique computed tomography. METHODS: Patients who underwent endoscopic sinus surgery at the Department of Otolaryngology, Toho University Medical Center Omori Hospital and were diagnosed with ECRS (106 patients) based on the Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis study were included. Subsequently, the presence of EOM accompanied by ECRS in 212 ear sides was assessed, and preoperative sinus computed tomography was used to evaluate various anatomical findings, such as the development of the sphenoid sinus and mastoid cells at the apex of petrous bone, the angle and length of the ET, and the size of the tympanic orifice of the ET. The relationships between these anatomical findings and the presence of EOM were analyzed statistically. RESULTS: EOM accompanied by ECRS was associated with a high peripheral blood eosinophil count and bronchial asthma. Among anatomical factors, the absence of peri-ET cells or petrous apex cells, and a low angle and short length of the ET, were risk factors for the onset of EOM. CONCLUSION: Anatomical factors such as the absence of peri-eustachian cells or petrous apex cells, and low angle or short length of the ET, are risk factors for the onset of EOM along with ECRS. Assessment of these factors may help in preventing the future onset or aggravation of EOM. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:E2689-E2695, 2021.

NSD3-NUTM1-rearranged carcinoma of the median neck/thyroid bed developing after recent thyroidectomy for sclerosing mucoepidermoid carcinoma with eosinophilia: report of an extraordinary case.

Sclerosing mucoepidermoid carcinoma with eosinophilia (SMECE) is an exceedingly rare low-grade thyroid malignancy of unknown histogenesis. NUT carcinoma is another rare, highly aggressive neoplasm with predilection for the midline, defined by recurrent NUTM1 fusions. The bromodomain family genes (BRD4 or BRD3) and rarely NSD3, ZNF532, or others are known fusion partners. We describe an extraordinary case of a 42-year-old female with a thyroid SMECE treated by thyroidectomy and neck dissection. She presented 6 months later with extensive midline recurrence encasing/compressing the trachea. Biopsy revealed poorly differentiated carcinoma with abrupt squamous differentiation, suggestive of NUT carcinoma. Immunohistochemistry confirmed expression of monoclonal NUT antibody. Targeted RNA sequencing revealed the NSD3-NUTM1 fusion in the NUT carcinoma, but not in the SMECE. This unique case highlights unusual sequential origin of two exceptionally rare entities at same anatomic site and underlines the necessity of sampling unexpectedly aggressive recurrences of otherwise indolent malignancies.

Surgical Treatment of Loffler Endocarditis in an 8-Year-Old Girl.

BACKGROUND: Idiopathic hyper eosinophilic syndrome (HES) is a rare disease characterized by a sustained increase in eosinophilia. Heart involvement is called Loffler endocarditis. Loffler endocarditis is a serious complication of hyper eosinophilia syndrome, which is characterized by a special type of fibrotic endocarditis. Loffler endocarditis is an inflammatory cardiac condition characterized by eosinophilic infiltration in the heart. The overall prognosis for patients with Loffler endocarditis is very poor. METHODS: In this article we report an 8-year-old girl who was diagnosed as having Loffler endocarditis in thrombotic phase and was successfully treated with surgery. RESULTS: Our patient had a good prognosis during the half-year follow-up. She had no symptoms of heart failure and echocardiography findings were normal. CONCLUSION: The cardiac damage occurred in a three-stage process: the necrotic, thrombotic, and fibrotic stages. This unusual but sometimes life-threatening disease is often detected in the late phase, resulting in no curative strategy available to reverse the disease process. The overall prognosis of patients with Loffler endocarditis is very poor. Current treatments include anticoagulation and anti-eosinophils therapy, and surgery only in selected cases. Surgical treatment of HES in adolescents is very rare. The present case illustrates that with well-controlled peripheral eosinophilia, proper surgical treatment in selected patients can improve their prognosis in the near future but long-term follow-up is necessary.

Enteritis eosinofílica, una causa extraña de abdomen agudo. reporte de caso clínico / Eosinophilic enteritis, a strange cause of acute abdomen Clinical case report

La enteritis eosinofílica, es una patología rara, caracterizada por infiltración de eosinófilos en una o más capas histológicas en diferentes niveles del tracto gastrointestinal, siendo el estómago e intestino delgado los más afectados; su cuadro clínico, inespecífico, caracterizado por dolor abdominal, náusea, vómito, diarrea o estreñimiento, pérdida de peso y ascitis, con presencia o ausencia de eosinofilia en la biometría. Reporte de caso Paciente masculino de 51 años de edad, acudió a emergencia por distensión abdominal y náusea, al examen físico en la palpación intenso dolor y distención abdominal, percusión timpánico y abolición de ruidos hidroaéreos. La analítica reportó leucocitosis con neutrofilia, radiografía de abdomen íleo adinámico, en la ecografía abdominal presencia de imágenes tubulares con aspecto de diana, asociado a líquido libre purulento en fosa ilíaca derecha y fondo de saco vésico rectal. Un cuadro clínico compatible con abdomen agudo de resolución quirúrgica, se realizó laparotomía exploratoria (AU);

The eosinophilic enteritis is a rare pathology, characterized by infiltration of eosinophils in one or more histological layers at different levels of the gastrointestinal tract, the stomach and small intestine being the most affected; its nonspecific clinical picture, characterized by abdominal pain, nausea, vomiting, diarrhea or constipation, weight loss and ascites, with the presence or absence of eosinophilia in the biometry. Enteritis eosinofílica, una causa extraña de abdomen agudo. reporte de caso clínico Eosinophilic enteritis, a strange cause of acute abdomen year-old male patient came to the emergency room due to abdominal distention and nausea, to physical examination on palpation, intense abdominal pain and distention, tympanic percussion and abolition of air-fluid sounds. Laboratory analysis reported leukocytosis with neutrophilia, abdominal ileus adynamic radiography, abdominal ultrasound presence of tubular images with a target appearance, associated with free purulent fluid in the right iliac fossa and rectal vesicum fundus. A clinical picture compatible with an acute abdomen with surgical resolution, an exploratory laparotomy was performed (AU);

A rare case of eosinophilic cholangiopathy.

Eosinophilic cholangiopathy is termed as a rare, benign, and self-limiting disease. Moreover, the interference of malignant tumor to diagnosis and the changing process of disease make the accurate treatment proposal challenging. A significant number of patients require surgery for the definitive diagnosis and resolution of symptoms. We put forward a case of eosinophilic cholangiopathy infiltrating the gallbladder and bile duct with bone marrow involved, coupled with peripheral eosinophilia. The patient underwent a successful treatment using laparoscopic cholecystectomy and steroids, instead of extrahepatic bile duct excision with Roux-en-Y hepaticojejunostomy. The patient gets an accurate treatment in a minimally invasive manner. In conclusion, surgery refers to not only a diagnostic methodology but also a treatment. When the bile duct and gallbladder are involved at the same time, and cannot distinguish benign and malignant diseases, laparoscopic cholecystectomy is feasible, the effect is the same, and the symptoms of eosinophilic cholecystitis are relieved.

EOSINOPHILIC ANGIOCENTRIC FIBROSIS AS A CAUSE OF NASAL OBSTRUCTION. A CASE REPORT.

Eosinophilic angiocentric fibrosis (EAF) is a rare benign lesion of unknown aetiology, found predominantly in the upper respiratory tract. The fibrosis must be confirmed by considering other lesions in the differential diagnosis. The typical histological characteristics are the basis for establishing the diagnosis. We present a patient with long-term nasal obstruction caused by EAF. The patient had repeated resections of the lesion for its recurrences. As follows from the literature, radical resection is crucial for the treatment of EAF. This procedure may be difficult at times given the extent and localization of the disease..

Resection of Massive "Tarry" Intra/Extra-ventricular Prepontine Colloid Cyst: 2-Dimensional Operative Video.

Colloid cysts are typically slow-growing lesions that account for approximately 1% of primary intracranial neoplasms and predominantly exist intraventricularly. These benign lesions typically can exist symptom-free for years and do not require surgical intervention. However, if the location of the colloid cyst is symptomatic, surgical debulking may be indicated. In this intraoperative video, we illustrate the case of an 8 cm, intra/extra-ventricular colloid cyst that appeared as a craniopharyngioma on preoperative imaging, but upon resection via a trans-middle temporal gyrus approach, was found to be very atypically filled with a thick, "tarry" substance, which we hypothesize is due to serial, subacute lesional hemorrhages. After debulking and piecemeal resection of the majority of the mass with ultrasonic aspiration and microsurgical tools, a hard, calcified nodule was left tenaciously adherent to the superior cerebellar artery to prevent damage to this vascular structure.

Severe Eosinophilic Myocarditis in the Portion of Left Ventricular Wall Excised to Insert a Left Ventricular Assist Device for Severe Heart Failure.

Described herein are 3 adults in whom histologic study of the left ventricular myocardium excised ("LV core") to insert a left ventricular assist device (LVAD) disclosed severe acute myocarditis and the inflammatory cells included numerous eosinophils (eosinophilic myocarditis). Examination of the clinical records disclosed elevated absolute eosinophil counts at the time of insertion of the LVAD and the counts rapidly (<30 days) returned to normal after the operation. Because of the numerous medications that each patient was taking at the time of LVAD insertion, identification of a specific initiating medication as its cause was not possible. Of the 3 patients, 2 had idiopathic-dilated cardiomyopathy and 1 had ischemic cardiomyopathy and each had had heart failure for years. The eosinophilic myocarditis in these 3 patients appears to have been transient and superimposed on the earlier cardiomyopathy.

Chronic rhinosinusitis in eosinophilic granulomatosis with polyangiitis: clinical presentation and antineutrophil cytoplasmic antibodies.

BACKGROUND: In this study we aim to describe presenting characteristics and identify prognostic factors for disease resolution in patients with chronic rhinosinusitis (CRS) in the setting of eosinophilic granulomatosis with polyangiitis (EGPA). METHODS: Patients evaluated at a tertiary care center with diagnoses of EGPA and CRS were identified. Descriptive statistics were obtained. Univariate analysis was used to search for prognostic factors associated with higher Lund-Mackay score at presentation and disease resolution. RESULTS: Forty-four patients were included with a mean age of 52.7 (standard deviation, 14) years. Twenty-one patients (47.7%) were female, all had a diagnosis of asthma, and 36 (83.7%) had eosinophils >10%. Common presenting symptoms for CRS included nasal discharge (87.9%) followed by nasal congestion (83.9%) and facial pain and pressure (83.8%). Medical management of CRS included systemic corticosteroids (93.2%) and systemic antibiotics (75%). Surgical intervention occurred in 29 patients (67%). Nine patients (20.5%) had resolution of sinus symptoms, including 4 with imaging confirmation. Fourteen patients (31.8%) had continued CRS, but with improved symptoms, whereas 9 patients (20.5%) had continued CRS with no improvement in symptoms. Eleven patients (25%) were lost to follow-up and 4 (9.1%) died. Univariate analysis did not show antineutrophil cytoplasmic antibody positivity, presence of peripheral eosinophilia, gender, age, or absence of systemic therapy to be predictive of higher Lund-Mackay score at presentation or predictive of disease resolution. CONCLUSION: CRS in patients with EGPA is often refractory to medical and surgical management. Treatment of these patients should occur in a multidisciplinary setting.

Short-term outcomes of olfaction in patients with eosinophilic chronic rhinosinusitis after endoscopic sinus surgery and an assessment of prognostic factors.

BACKGROUND: Olfactory dysfunction is one of the common symptoms of eosinophilic chronic rhinosinusitis (ECRS), for which endoscopic sinus surgery (ESS) is the standard treatment. Although the success rates of ESS for restoring olfaction in CRS have been reported, those for ECRS, as defined by new Japanese diagnostic criteria, remain unclear and the parameters affecting improvement rates have not yet been identified. METHODS: Eighty-four patients with ECRS who underwent full-house ESS were retrospectively investigated. Olfactory function was examined using T&T recognition thresholds before and 3 months after surgery. RESULTS: The total positive improvement rate in olfaction was 76.2% (64 of 84) and the mean T&T recognition threshold decreased significantly from 5.2 ± 1.1 to 3.0 ± 1.8 after surgery (p < 0.001). Some factors, including negative intravenous olfaction test, presence of olfactory cleft (OC) lesions, a history of sinus surgery, age ≥ 45 years, and being male, were more frequent in the olfaction refractory group. Furthermore, improvement of the T&T recognition threshold was significantly lower for factors of negative intravenous olfaction testing, the presence of OC lesions, and being male. Age and the proportion of blood eosinophils correlated with improvement. CONCLUSION: Herein we examined prognostic factors for olfactory outcomes in ECRS treated with ESS. The intravenous olfaction test, presence of OC lesions, sex differences, and age (the cut-off value was 45 years) were identified as independent prognostic factors for olfactory outcomes 3 months after surgery.

Right atrial myxoma with peripheral eosinophilia: Eosinophilia in cardiac myxoma.

BACKGROUND: Cardiac myxoma is the most common type of primary cardiac tumors. It is known that inflammatory markers are increased in the setting of myxoma, like C-reactive protein, erythrocyte sedimentation rate, and interleukin-6. The association between cardiac myxoma and abnormal blood cell counts has been scarcely reported. RESULTS: We present a patient with a right atrial myxoma found incidentally, who had hypereosinophilia, which dramatically resolved after resection of the tumor. CONCLUSION: Hypereosinophilia has mostly been found in patients with heart malignancies. It is extremely uncommon in patients with cardiac myxoma; therefore, its presence may signify a distinct biological tumoral behavior with the potential to become a marker of disease activity or recurrence. The true significance of this finding is still unknown and requires further investigation.

The relationship of eosinophilia with outcomes of Hirschsprung disease in children.

PURPOSE: It has been postulated that children with Hirschsprung disease (HD) and mucosal eosinophilia have been thought to have poorer outcome, but supporting evidence is lacking. The objective of our study was to review the outcomes of children with HD and mucosal eosinophilia. METHODS: A single center, retrospective review was conducted on all patients diagnosed with HD between 1999 and 2016. Pathology specimens were evaluated for mucosal eosinophilia. Demographics, complications, and outcomes were analyzed. RESULTS: A total of 100 patients were diagnosed with HD and 27 had mucosal eosinophilia. Median age at the time of surgery was 12 days (8, 30) and 82 were males. Comparing patients with HD with and without mucosal eosinophilia, there was no statistically significant difference in time to bowel function (2 days vs. 2 days; p = 0.85), time to start feeds (3 days vs. 3 days; p = 0.78) and time to goal feeds (5 days vs. 5 days; p = 0.47). There was no statistically significant difference in feeding issues (13% vs. 9%; p = 1.0) and stooling issues (60% vs. 50%; p = 0.38). There was no statistically significant difference in postoperative complications and readmissions rates (63% vs. 56%; p = 0.53). CONCLUSION: Hirschsprung-associated mucosal eosinophilia may not increase postoperative complications, and may not change feeding and bowel management. Further prospective studies are in process to evaluate long term follow-up outcomes for this patient population.

Histological characteristics of eosinophilic myenteric ganglionitis: an under-recognised cause of chronic intestinal pseudo-obstruction.

Eosinophilic myenteric ganglionitis (EMG) is characterised by eosinophilic infiltration of the myenteric plexus. EMG has been rarely reported as a cause of chronic intestinal pseudo-obstruction (CIPO), and its histopathological features are not fully elucidated. We analysed seven patients with CIPO. Three of them were diagnosed with EMG and four patients were categorised as non-EMG. Clinicopathological features were similar in both groups. These features included subtle to mild lymphocytic infiltration at the myenteric ganglia/muscularis propria, loss of myenteric ganglions and interstitial cells of Cajal (ICC), and no significant findings in the mucosa. The exceptions were moderate to severe degree of eosinophilic infiltration at the myenteric ganglia/muscularis propria in EMG. Functional gastrointestinal obstruction may be associated with inflammatory cell infiltration at the myenteric ganglia/muscularis propria, leading to subsequent hypoganglionosis and deficiency of ICC in EMG. Pathologists and clinicians should be aware of this distinction during differential diagnosis of patients with CIPO.

Reduced nasal nitric oxide levels in patients with eosinophilic chronic rhinosinusitis.

BACKGROUND: In Eosinophilic chronic rhinosinusitis (ECRS), it is difficult to estimate the refractoriness and recurrence risk for each patient. Fraction of exhaled nitric oxide (FeNO) is known as a biomarker of eosinophilic inflammation in lower airway. It has been reported that nasal NO has some crucial functions in the upper and lower airways. However, in upper airway, paranasal sinuses, the usefulness of NO measurement remains controversial. The purpose of this study is to identify the usefulness of nasal NO measurement in ECRS and the involvement of nasal NO in the pathogenesis of ECRS. METHODS: We compared the nasal NO levels of ECRS, non-ECRS, and normal control groups. Correlation between nasal NO levels and clinical findings were observed. Then, we compared nasal NO levels before and after endoscopic sinus surgery (ESS). We also examine whether nasal NO levels might discriminate ECRS by the receiver operating characteristic (ROC) curve analysis. RESULTS: Nasal NO levels were significantly decreased in ECRS compared to the other two groups. Moreover, nasal NO levels in ECRS significantly and negatively correlated with eosinophil levels and CT score. However, they did not correlate with the nasal polyp score. Nasal NO levels were not upregulated soon after opening the sinus ostium by ESS. The ROC curves for nasal NO levels were used to discriminate all CRS patients and ECRS patients from normal controls. CONCLUSIONS: Nasal NO may be useful as a marker of ECRS severity and low nasal NO levels in ECRS may contribute to its pathogenesis.