Use of Nasal Cytology in Diagnosis of Sinonasal Disorders

*Marco Capelli*

### **Abstract**

Nasal cytology is an important diagnostic tool in nasal disorders, especially those regarding nasal mucosa. This technique allows clinicians to observe the morphology and the structure of nasal epithelium cells—such as ciliated, mucous-secreting, striated, and basal cells—and to detect the presence of degenerative or phlogistic phenomena in the respiratory epithelium. Moreover, it makes it easy to identify the presence of inflammatory cells, such as neutrophils, eosinophils, and mast cell. Over the past few years, nasal cytology allowed researchers to discover new clinical issues that were still unexplored: the nonallergic rhinitis with eosinophils, the nonallergic rhinitis with mast cells, the nonallergic rhinitis with neutrophils, and the nonallergic rhinitis with eosinophils and mast cells. Nasal cytology is easy to perform and barely invasive; therefore, it can easily be repeated. Since it makes it possible to evaluate the patient's response to a therapy, the technique is a very useful tool in follow-up checks of nasal disorders. We have reported in the following chapter our working experience, and we observed the results of cytological exams performed in our Center from 2013 to 2018. We therefore developed an easy and intuitive classification of sinonasal chronic inflammatory diseases.

**Keywords:** nasal cytology, rhinosinusitis, neutrophils, eosinophils, classification

### **1. Introduction**

The nose is composed of two nasal cavities separated by an osteocartilaginous structure called nasal septum. The initial portion is called nasal vestibule, while the next part is called nasal cavity. The nasal cavity borders on the nasopharynx, from which it is separated by the choanae. In the most cranial portion of the nasal fossa, we find the olfactory fissure. This region is responsible for the perception of odorous stimuli. The nasal cavities are occupied by osseous structures with mucous lining called turbinates. These are divided as follows: the inferior turbinate that through its cavernous vascular tissue contributes to humidify and heat the inspired air, the middle turbinate that anatomically defines a sort of pre-sinus space, and at last the superior turbinate. In some cases we also recognize a fourth turbinate called supreme [1].

We observe four different nasal epithelia. A layered keratinized floor epithelium covers the region of the nasal vestibule, and an epithelium called transitional is located at the level of the valve. On the other hand, the nasal cavities are covered by a mucosa with pseudostratified ciliated epithelium (enriched with olfactory cells at the level of the olfactory fissure). The ciliated pseudostratified epithelium is composed of four types of cells: ciliated cells, muciparous cells, columnar cells, and basal cells, anchored by desmosomes and hemidesmosomes. This epithelium is separated from

the underlying tonaca propria by a basal membrane. In the context of the tonaca propria, we can find three layers. At the beginning, just below the basement membrane, we can find the lymphoid layer, which is characterized by the richness of lymphocytes (nasal-associated lymphoid tissue (NALT)). Then we have the glandular layer, characterized by glands that have a significant immune function producing secretions rich in lysozyme and IgA. Last, we can find the vascular layer, characterized by important vascular representation, especially in the mucosa of the inferior turbinate [2].

This brief description of microscopic anatomy of the nasal mucosa allows us to highlight the many important physiological functions it performs.

First of all, in the respiratory epithelium, the mucociliary clearing action is carried out thanks to the cooperation of ciliated and muciparous cells. This process is fundamental in determining the circulation of mucus, and therefore it performs a nasal cleaning with immuno-protective tasks [3]. At the level of the superficial mucous layer (thanks to the presence of lymphatic tissue) and at the level of the intermediate glandular layer (thanks to the secretion of lysozyme and IgA), immunocompetence functions are also performed. At last, the vascular layer, thanks to the presence of cavernous tissue, allows to change the physical-chemical characteristics of the air inhaled before its passage in the middle and lower respiratory tract [2]. With the passage of air through the nasal cavities, water vapor is transferred through the mucosa of the inferior turbinates with consequent lowering of oxygen partial pressures [4]. Furthermore, due to the contact between the mucosal surface of the turbinate and the air, the heating of the same is ensured [5].

The pathology of the rhinosinusal district appears to be varied and diversified [2], and it is characterized by many different types of clinical entities that sometimes are present individually, sometimes they overlap: this creates, in our opinion, classification difficulties. Another critical aspect for clinicians is to understand the real extent of rhinosinus disease, that is, if we are dealing with an exclusively nasal or sinus involvement or an involvement of both districts.

Our experience has led us to use in diagnosis of a rhinosinusopathy both a cytological examination of the nasal mucosa that will allow us to identify the problem and a radiological study (better if using cone beam CT) to define the real extent of the problem.

In this discussion we will explain how to perform a cytological examination and how to interpret it, and we will try to define a systematic classification of rhinopathies relying on the analysis of cytological compartments of patients affected by rhinopathy from our Center in the last 5 years.

#### **2. Materials and methods**

For about 10 years, we have been analyzing cytological samples from the lower turbinate mucosa in patients with chronic rhinopathies. This type of evaluation allowed us to study the microscopic characteristics of the healthy nasal mucosa and to identify the characteristic aspects of the different forms of rhinopathy. Performing a cytological examination is simple, rapid, and minimally invasive. It is also a cost-effective investigation.

From October 2013 to September 2018, we performed cytological sampling and subsequent microscopic analysis on the sample obtained from 300 patients with chronic rhinopathy. These patients reported suffering from several months or even years of nasal respiratory obstruction, rhinorrhea, in some cases complaining of recurrent headache or hyposmia or sneezing and nasal itching.

The cytological examination of each patient was performed according to the Italian Academy of Nasal Cytology (AICNA) procedures. We briefly summarized the modalities in the following paragraph.

**31**

**Table 1.**

*Classification of rhinosinusitis.*

*Use of Nasal Cytology in Diagnosis of Sinonasal Disorders*

Through a small spoon called Rhino-Probe®, we collect mucous material joined to cells of the nasal mucosa, exerting a slight pressure on the body of the inferior turbinate. This technique is called nasal scraping (there are other sampling techniques such as brushing, nasal swab, and the washing that we report but of which

The material taken is distributed on a special slide, while avoiding to touch the

Through a specific synthetic product (Bio Mount HM®) the cover slip is applied

The analysis of the sample of cytology material mounted on the slide is done with an optical microscope equipped with multiple objectives, each with different

We proceed to fix the material taken on the slide, then we apply the May-Grunwald-Giemsa (MGG) coloration. In our experience, we have been using a fastacting MGG staining method (MGG Quick Stain®) for some years now. Cytological staining method is very numerous and each of them has its own specificity and application. In nasal cytology the most widely used is the MGG method which is

able to easily differentiate the various cells found in the nasal mucosa.

above the slide. This way, the sample is ready to be observed.

surface of the slide with your fingers while always using gloves.

*DOI: http://dx.doi.org/10.5772/intechopen.84231*

*2.1.1 Sampling*

*2.1.2 Processing*

we have no experience).

*2.1.3 Fixation and coloring*

*2.1.4 Assembly of the slide*

**2.2 Microscopic observation**

magnification power.

**2.1 How to perform a cytological sampling**
