Cytology in the diagnosis of rhinosinusitis.

Nasal cytology is a diagnostic tool currently used in rhinology, with the aim of assessing cell changes in the nasal epithelium exposed to irritant or inflammatory agents. Its rationale is based on the knowledge that nasal mucosa of healthy individuals is constituted by four cytotypes (ciliata, mucipara, striata, and basalis) and does not show other cells except, rarely, neutrophils and, very rarely, bacteria. In this view, the detection of a given cell type different from these is a sign of possible pathology. The advantage and the diffusion of nasal cytology were increased by a number of factors such as the easiness of performance, the non-invasiveness allowing repetition (which is often needed in the efficacy monitoring of medical or surgical treatment of nasal diseases), and the low cost. This makes nasal cytology particularly feasible for application in children. The cytological feature characterizing infectious inflammation is the presence of abundant bacteria, which may be found in extracellular tissue and also inside neutrophils as a result of phagocytosis. In such clinical condition it is important to monitor the disease with cytological controls to verify the significant decrease, or the disappearance of inflammatory cells, which indicates the resolution of the pathology.