Pathology of the Head and Neck

Nasal Cavity and Paranasal Sinuses Chapter 2 41hyperplasia of the respiratory epithelium and the basementmembrane, which is destroyed in the acute phase,appears considerably thickened in the chronic phase.2.2.4 Atrophic RhinitisAtrophic rhinitis is a chronic inflammation of the nasalmucosa of unknown aetiology characterised by progressivenasal mucosal atrophy and by a thick, dense secretion,with a foetid smell and crusting [178]. Multiplefactors may be involved in the pathogenesis, includingchronic bacterial infections and nutritional deficiencies.Its incidence has markedly decreased in the last century,and nowadays most cases are secondary to trauma,surgery, granulomatous diseases, infection and radiationexposure [178]. Histologically, there is non-specificchronic inflammatory infiltrate, squamous metaplasiaof the surface epithelium and of glandular excretoryducts, and atrophy of mucoserous glands [1, 69].2.2.5 Hypertrophic RhinitisThis term is applied to a condition of unknown aetiology,characterised by thickening of the sinonasal mucosaresulting from chronic inflammatory diseases [28, 71].Frequently, these patients have undergone several sinusoperations, each time with limited success and subsequentrecurrence. Recurrent nasal polyposis is often associated.2.2.6 Non-Suppurative Chronic SinusitisChronic sinusitis is a complex, multifactorial disorderresulting from persistent acute inflammation or repeatedepisodes of acute or subacute sinusitis. There are usuallypredisposing factors like small sinus ostia, repeatedepisodes of common cold, allergy or acute sinusitisdetermining obstruction of the sinus ostia, reductionof ciliary activity (immotile cilia syndrome) and cysticfibrosis. The mucosal changes observed are variableand include basement membrane thickening, goblet cellhyperplasia, oedema of varying extent, inflammation(mostly lymphocytes and plasma cells) and polypoidchange of the mucosa [242].Allergic sinonasal polyps consist largely of myxoidoedematous tissue with pseudocysts containing eosinophilicproteinaceous fluid and infiltrates of inflammatorycells [115]. They are covered by respiratoryepithelium with variable ulceration, goblet cellhyperplasia, squamous metaplasia and thickening ofthe basement membranes. Seromucous glands andmucin-containing cysts may also occur. They arisemost frequently in the ethmoidal region and the upperpart of the nasal cavity. Allergic polyps usually exhibitheavy infiltration by eosinophils (Fig. 2.1a), markedthickening of the basement membranes and gobletcell hyperplasia. Most sinonasal polyps are of allergicorigin. Epithelial dysplasia is present in a few cases.Granulomas may be present in polyps treated withintranasal injection, application of steroids or otheroily medications. Atypical fibroblasts with abundantcytoplasm, poorly defined cell borders and large pleomorphicnuclei are present in a small proportion ofcases [183]. These atypical cells occur individuallyand are more frequently found close to blood vessels(Fig. 2.1b) or near the epithelial surface. Such stromalatypia is a reactive phenomenon and it should not beconfused with sarcoma.2.3.2 Polyposis in MucoviscidosisNasal polyps in mucoviscidosis show cystic glands filledwith inspissated mucoid material and thickening of thebasement membranes that surround the glands [22,189]. Some other polyps are of infective or chemical aetiology.The histological appearances of nasal polyps donot always correlate well with their aetiology.2.3.3 Polyposisin Immotile Cilia Syndromeand Kartagener’s SyndromeImmobile cilia syndrome (or primary ciliary dyskinesia)is a genetic disease affecting ciliary movementand resulting in respiratory infections and male infertility.Situs inversus may be associated ( Kartagener’ssyndrome). About 15% of patients develop nasal polypshistologically indistinguishable from other nasalpolyps. Ultrastructural analysis of nasal biopsies isneeded to identify the alterations in the architecture ofthe cilium [177].2.3 Sinonasal Polyps2.3.1 Allergic Polyposis2.3.4 Antrochoanal PolypsAntrochoanal polyps are polyps that arise in themaxillary antrum and extend into the middle meatusprojecting posteriorly through the ipsilateral choana[106]. Antrochoanal polyps typically have prominentfibrous stroma surrounding thick-walled blood vessels