Introduction
The study of disease has progressed from an era focused on phenotype,
where all information was collected by the physician in collaboration
with the patient, with or without the use of tools such as the
stethoscope, endoscope, X-ray and Ct scanner. We have witnessed the
incorporation of ever more sophisticated laboratory-based findings,
collected via microscopy and instruments developed for biochemistry,
molecular biology and immunochemistry. Information gleaned by these
modern techniques can provide information on the underlying cellular and
molecular mechanisms that define the endotype. The purpose of this
review is to discuss the phenotypic and endotypic heterogeneity of
chronic rhinosinusitis from the perspective of advancing the
understanding of the pathogenesis and improvement of treatment
approaches and outcomes.