Review article: Nasal polyposis: a cellular‐based approach to answering questions

Abstract

Nasal polyposis (NP) is a common chronic inflammatorydisease of the nasal mucosa that has a major impact onpatients lives. NP is characterized by benign polypoustissue swellings in the nose that originate from theparanasal sinuses, most often from the anterior ethmoidcomplex (Figs 1 and 2) (1). From there the polyps candescendbetweenthemiddleturbinateandthelateralnasalwall into the nasal cavity causing symptoms such as nasalcongestion, rhinorrhea, hyposmia and facial pressure (2).Treatment with corticosteroids alleviates symptoms,but no curative treatment exists. Often patients requirerecurrent operations and this, in combination with thesymptoms, has a significant effect on the patients qualityof life (3, 4). When tested by means of a disease-independent questionnaire (SF-36), the quality of life inthese patients is worse than in patients suffering fromhypertension, migraine, angina pectoris and head andneck cancer. NP patients have comparable quality of lifescores as patients with chronic obstructive pulmonarydisease (5). Unfortunately, the aetiology of NP is largelyunknown. Although some hypotheses have focused onthe possible involvement of micro-organisms in theaetiology of NP, this has not yet developed into asuccessful treatment alternative.This review aims at discussing some of the difficultiesand pitfalls in NP research, and to identify the importantcellular players and interactions in the pathophysiologyof NP. We would also like to suggest potential relevantfuture directions for research. Understanding the patho-genesis of NP may lead to new treatment options for thisincapacitating disease.Difficulties in NP researchFundamental research into the pathogenesis of NP ishampered by two problems. First, it is unclear how themany different clinical phenotypes of NP influence thepathogenesis. Secondly, it is not clear whether NP shouldbe considered a local disease or a local manifestation of asystemic disease.Many co-morbidities have been described in NP thataffect the prevalence of NP. In the general population theprevalence is 0.5–4.3%, making it one of the mostcommon chronic diseases of the upper respiratory tract.The prevalence of NP is increased in patients with asthma(7–15%), cystic fibrosis (39–56%) or aspirin intolerance(36–96%). Interestingly, although the prevalence isincreased in asthma, this does not seem to hold true forpatients with allergic rhinitis, where the prevalence of NPis unchanged (0.5–4.5%) (2, 6). Chronic rhinosinusitis(CRS) almost always coexists with NP, but the converseis not true, only about 20% of the patients with CRSdevelop nasal polyps (7). Evidence accumulates that CRSwith NP and CRS without NP actually are two differentdisease entities (8, 9).A. B. Rinia