Epithelial atypia and squamous metaplasia in nasal polyps

Nasal polyp epithelial atypia and exposure to nickel and copper

BACKGROUND

Possible factors for cell atypia in nasal mucosa include noxious chemicals: ammonia, formaldehyde and heavy metals.

AIMS

Case presentation of a nasal polyp with epithelial dysplasia in a worker exposed to nickel and copper salt dust.

CASE REPORT

A 27-year-old man complained of impaired nasal breathing and mild right-sided epistaxis. He was exposed to copper and nickel salt dust for 6 years. Clinical examination showed a polypoid lesion arising from the right middle turbinate. Histopathological examination of the excised lesion showed high-grade epithelial dysplasia. Duration of exposure and concentration of heavy metals in serum suggest the biological plausibility of exposure to these factors and development of epithelial dysplasia in the nasal mucosa.

CONCLUSIONS

Epithelial dysplasia may occasionally be noted in inflammatory nasal polyps, especially in workers exposed to heavy metals.

Histopathological Features of Chronic Rhinosinusitis with Nasal Allergic Polyps

Chronic rhinosinusitis with nasal polyps of allergic etiology is one of the most common pathology in the ENT sphere that affect a significant percentage of population. The paper aims to establish the involvement of the allergic component in the genesis of nasal polyposis. The study included 150 nasal polyps from patients hospitalized and operated in the ENT Department of Craiova's Clinical Emergency County Hospital. The biological material was fixed in 10% buffered formalin, processed by classical paraffin embedding technique followed by hematoxylin-eosin staining and it was interpreted in the Pathology Department of the same hospital. We evaluated a number of histopathological parameters that were given severity scores. The most common changes at epithelial level were: basal layer hyperplasia observed in 87 cases (58%), goblet cell hyperplasia in 121 cases (80.66%), basal membrane thickening with values between 10-42μm corresponding to a number of 118 cases (78.66%). The most important stromal changes were edema in 88% and infiltration with eosinophils 100%, indicating the allergic nature of this disease.

Current Understanding of Nasal Epithelial Cell Mis-Differentiation

The functional role of the respiratory epithelium is to generate a physical barrier. In addition, the epithelium supports the innate and acquired immune system through various cytokines and chemokines. However, epithelial cells are also involved in the pathogenesis of various respiratory diseases, some of which are mediated by increased permeability of the mucosal membrane or disturbed mucociliary transport. In addition, it has been shown that epithelial cells are involved in the development of inflammatory respiratory diseases. The following review article focuses on the aspects of epithelial mis-differentiation, in particular with respect to nasal mucosal barrier function, epithelial immunogenicity, nasal epithelial-mesenchymal transition and nasal microbiome.

Epithelial Squamous Metaplasia and Dysplasia in Inflammatory Nasal Polyps: An Observational Study

Nasal polyposis (NP) is characterized by polypoid outgrowths of chronically inflamed respiratory mucosa. The presence of squamous metaplasia and dysplasia on the mucosal surface of nasal polyps (NPs) represents different manifestations of epithelial atypia. The aim of this investigation was to evaluate the presence of epithelial squamous metaplasia and dysplasia in ethmoidal NPs. This retrospective analysis of prospectively collected data involved 212 patients with NP undergoing endoscopic ethmoidectomy. To evaluate possible etiological factors for epithelial atypia, the patients in whom we histopathologically detected the presence of epithelial atypia were compared with patients with "normal" NPs in accordance with the following characteristics as found in the patients' medical records: gender, age, main symptoms, preoperative extent of sinus disease on computed tomography, atopic status, aspirin sensitivity, cigarette smoking, and occupational exposure to different noxious factors. Epithelial atypia were detected histopathologically in 44 (20.7%) NP patients, whereas features of "true" dysplasia were found in only 1 (0.5%) patient. The presence of atypia was more frequent in males than in females (P = .008). The association with aspirin-exacerbated respiratory disease and with long-term occupational exposure to different noxious chemicals, especially in workers exposed to salts of heavy metals, was more frequent in NP patients with epithelial atypia than in patients without atypia (P = .023; P = .006, respectively). Our results suggest epithelial atypia in NPs are associated with aspirin sensitivity and occupational exposure to different noxious chemicals. Although extremely rare, epithelial dysplasia may occasionally be noted in NPs, a fact potentially useful for both rhinologists and pathologists.

Ultrastructural investigation of epithelial damage in asthmatic and non-asthmatic nasal polyps

Nasal polyposis is a poorly understood chronic inflammatory disease often associated with asthma. As nasal polyps and asthma both are associated with massive eosinophil infiltration, they may share a common pathophysiological mechanism. Many genetic and autoimmune diseases may result from altered expression or function of cell adhesion molecules such as desmosomes. A transmission electron microscopical study was carried out on tissue from 15 patients suffering from nasal polyps, to investigate if there are changes in desmosomes in nasal polyps from asthmatic and/or allergic patients versus non-asthmatic versus non-allergic patients. In allergic patients the damage to columnar cells was more extensive than in non-allergic patients. Massive infiltration of eosinophils was observed in epithelium and connective tissue in all groups. No significant difference in thickness of the basal lamina was found between any of the groups. All patients had dilated capillaries in the connective tissue. The intercellular space between the epithelial cells was smallest in the asthmatic non-allergic group. The relative length of columnar cell or basal cell desmosomes was reduced in patients with asthma or allergy, compared to non-allergic, non-asthmatic patients. Hence, there appears to be a weakness in the desmosomes in asthmatics and allergics. Epithelial shedding may play an important role in the pathophysiological process of a multifactorial disease such as asthma.

DNA microarray gene expression analysis of a vocal fold polyp and granuloma

Genome-wide transcriptional profiling has important applications in advancing knowledge of vocal fold biology. With the use of DNA microarray technology, analysis of global patterns of gene expression can reveal unexpected networks of coordinated regulation in the extracellular matrix of the lamina propria. Transcriptional gene expression patterns for 2 vocal fold pathologies--vocal fold polyp (VP; N = 1) and vocal fold granuloma (VG; N = 1) were analyzed by means of DNA microarray analysis for 4,632 human genes using another patient's true vocal fold (TVF; N = 1) as a control. Twenty-four and 29 genes for VG and VP, respectively, were established to be either over- or underexpressed compared to that of TVF. Five-way cluster analysis revealed broad patterns that suggest a potential degree of organization underlying gene expression in these tissues. For the 1 VG, genes involved represent inflammation and wound healing; for the 1 VP, involved genes demonstrate a tempered wound repair response and increased epithelial manifestations. These results successfully demonstrate the use of DNA microarray technology as a new approach for further investigations dissecting vocal fold disease. Further investigation is needed on larger sample sizes to establish transcriptional gene expression patterns for VP and VG.